Merge branch 'main' of https://github.com/ChuckBuilds/LEDMatrix into claude/fonts-used-by

CHANGELOG.md

@@ -66,6 +66,35 @@ core, the monorepo or the registry's third-party plugins calls them:
   instead of handing `config.json` to root, and an install path with
   "secrets" in a directory name no longer makes `config.json` mode 0640.
 
+New names in existing modules (no new modules; a plugin importing these must
+floor on the release that ships them):
+
+- `src.common.api_helper`: `USER_AGENT`, `DEFAULT_HTTP_HEADERS` (read-only).
+- `src.logo_downloader`: `fetch_logo`, `save_png_atomically`,
+  `shared_downloader`.
+
+### Logo downloads
+
+- `download_missing_logo` / `LogoDownloader.download_logo` (the path the
+  scoreboard plugins use) now stream the logo with a 10 MB cap, accept only an
+  `image/*` response that Pillow can decode, and move the finished RGBA PNG
+  into place atomically. A failed, oversized or non-image download no longer
+  leaves a partial file behind, and no longer replaces a logo already on disk.
+  `LogoHelper._download_logo` goes through the same code. Signatures and return
+  values are unchanged; saved files are pixel-identical to before.
+- `download_missing_logo` reuses one downloader (one `requests.Session`) per
+  thread instead of building a new one for every logo.
+- Placeholder logos are written atomically, without the `test_write.tmp`
+  probe file.
+
+### HTTP headers
+
+- The logo downloader and the background data service send the real
+  `LEDMatrix/1.0 (+https://github.com/ChuckBuilds/LEDMatrix)` User-Agent
+  instead of a `yourusername` / `contact@example.com` placeholder, and no
+  longer set `Accept-Encoding: ... br` by hand (brotli is not installed, so a
+  `br` response could not be decoded); requests picks the encodings.
+
 ## 3.5.0
 
 New modules a plugin may import via `src.*` (floor on 3.5.0):

src/background_data_service.py

@@ -172,14 +172,10 @@ class BackgroundDataService:
         self.session.mount('http://', requests.adapters.HTTPAdapter(max_retries=3))
         self.session.mount('https://', requests.adapters.HTTPAdapter(max_retries=3))
         
-        # Default headers
+        # Default headers: core's shared set (real User-Agent, no hand-set
-        self.default_headers = {
+        # Accept-Encoding) -- see src/common/api_helper.py.
-            'User-Agent': 'LEDMatrix/1.0 (https://github.com/yourusername/LEDMatrix)',
+        from src.common.api_helper import DEFAULT_HTTP_HEADERS
-            'Accept': 'application/json',
+        self.default_headers = dict(DEFAULT_HTTP_HEADERS)
-            'Accept-Language': 'en-US,en;q=0.9',
-            'Accept-Encoding': 'gzip, deflate, br',
-            'Connection': 'keep-alive'
-        }
         
         logger.info(f"BackgroundDataService initialized with {max_workers} workers")
     

src/common/api_helper.py

@@ -8,14 +8,32 @@ Extracted from LEDMatrix core to provide reusable functionality for plugins.
 import logging
 import time
 from datetime import datetime
+from types import MappingProxyType
 from src.common.espn_dates import ESPN_MAX_LIMIT
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Mapping, Optional
 
 import requests
 from requests.adapters import HTTPAdapter
 from urllib3.util.retry import Retry
 
 
+#: The User-Agent core sends to ESPN and other data APIs. It names the client
+#: and links to it: around 2026-08-04 ESPN began 403ing bare custom tokens
+#: (and browser strings), and this form is what it accepts.
+USER_AGENT = 'LEDMatrix/1.0 (+https://github.com/ChuckBuilds/LEDMatrix)'
+
+#: Base headers for core's JSON API requests. Read-only; pass
+#: ``{**DEFAULT_HTTP_HEADERS, ...}`` to add to it. There is deliberately no
+#: Accept-Encoding: requests advertises only what urllib3 can decode here
+#: (``br`` needs the optional brotli package, which is not a requirement), so a
+#: hand-set ``br`` invites a body the client cannot read.
+DEFAULT_HTTP_HEADERS: Mapping[str, str] = MappingProxyType({
+    'User-Agent': USER_AGENT,
+    'Accept': 'application/json',
+    'Accept-Language': 'en-US,en;q=0.9',
+})
+
+
 class APIHelper:
     """
     Helper class for HTTP requests, caching, and ESPN API integration.
@@ -57,12 +75,9 @@ class APIHelper:
         
         # Default headers
         self.session.headers.update({
-            # Identifies the client and links to it: ESPN began 403ing bare
+            'User-Agent': USER_AGENT,
-            # custom tokens (and browser strings) around 2026-08-04.
-            'User-Agent': 'LEDMatrix/1.0 (+https://github.com/ChuckBuilds/LEDMatrix)',
             'Accept': 'application/json',
             'Accept-Language': 'en-US,en;q=0.9',
-            'Accept-Encoding': 'gzip, deflate, br',
             'Connection': 'keep-alive'
         })
         

src/common/logo_helper.py

@@ -6,19 +6,16 @@ Extracted from LEDMatrix core to provide reusable functionality for plugins.
 """
 
 import logging
-import os
-import tempfile
 import time
 from pathlib import Path
 from typing import Dict, List, Optional, Union
 
 import requests
 from PIL import Image
+from src.common.api_helper import USER_AGENT
 from src.common.permission_utils import (
     ensure_directory_permissions,
-    ensure_file_permissions,
     get_assets_dir_mode,
-    get_assets_file_mode
 )
 
 # How long a missing logo stays remembered as missing.
@@ -61,6 +58,7 @@ def _usable_scale(scale) -> float:
 
 
 # Well above any real team logo; bounds what a remote URL can write to disk.
+# The cap for every logo download: src.logo_downloader.fetch_logo uses it too.
 MAX_LOGO_BYTES = 10 * 1024 * 1024
 
 
@@ -107,7 +105,7 @@ class LogoHelper:
         # Session for HTTP requests
         self.session = requests.Session()
         self.session.headers.update({
-            'User-Agent': 'LEDMatrix-Common/1.0',
+            'User-Agent': USER_AGENT,
             'Accept': 'image/*',
         })
     
@@ -408,64 +406,23 @@ class LogoHelper:
         self._cache_order.append(cache_key)
     
     def _download_logo(self, url: str, file_path: Path) -> None:
-        """Download logo from URL.
+        """Download a logo from ``url`` to ``file_path``; raises on failure.
 
-        The response size is capped and the saved file is verified as a
+        Delegates to ``src.logo_downloader.fetch_logo``, the same hardened
-        decodable image before it is left on disk: a logo URL is remote
+        download the scoreboard plugins use: streamed and capped at
-        input, and without this an oversized or malformed response would
+        ``MAX_LOGO_BYTES``, ``image/*`` only, decoded by Pillow, stored as an
-        be cached for every later load_logo() call to trip over.
+        RGBA PNG, and moved into place atomically -- a failure leaves neither
+        a partial file nor a temp file. Uses this helper's own session.
 
-        The body is streamed and counted as it arrives rather than read
+        Imported lazily: src.logo_downloader imports src.common, so a
-        through response.content, which buffers the whole thing first —
+        module-level import here would be circular.
-        a server that omits Content-Length and never stops sending would
-        exhaust memory before any size check could run. Nothing lands at
-        file_path until the download completes and decodes, so a failed
-        download cannot leave a truncated logo behind either.
         """
+        from src.logo_downloader import fetch_logo
+
         # Ensure directory exists with proper permissions
         ensure_directory_permissions(file_path.parent, get_assets_dir_mode())
-
+        fetch_logo(self.session, url, file_path, timeout=30,
-        # A unique temp name, not a fixed "<name>.part": two plugins can
+                   max_bytes=MAX_LOGO_BYTES)
-        # ask for the same logo at once, and a shared name would let them
-        # interleave writes into one file, publish the mixture, or delete
-        # each other's partial. Same directory, so os.replace stays atomic.
-        fd, tmp_name = tempfile.mkstemp(
-            dir=str(file_path.parent), prefix=file_path.name + '.', suffix='.part')
-        tmp_path = Path(tmp_name)
-        try:
-            # fdopen outermost so the descriptor mkstemp handed back is
-            # always adopted and closed, including when the request itself
-            # raises — load_logo_with_download swallows that, so a leak
-            # here would accumulate quietly on a URL that keeps failing.
-            with os.fdopen(fd, 'wb') as f:
-                with self.session.get(url, timeout=30, stream=True) as response:
-                    response.raise_for_status()
-                    downloaded = 0
-                    for chunk in response.iter_content(chunk_size=64 * 1024):
-                        if not chunk:
-                            continue
-                        downloaded += len(chunk)
-                        if downloaded > MAX_LOGO_BYTES:
-                            raise ValueError(
-                                f"Logo at {url} exceeds the "
-                                f"{MAX_LOGO_BYTES}-byte limit; not saved")
-                        f.write(chunk)
-
-            # Verify it decodes before it becomes the cached logo. PIL
-            # raises DecompressionBombError past its own pixel limit; a
-            # partial or non-image response raises UnidentifiedImageError
-            # (an OSError subclass).
-            with Image.open(tmp_path) as probe:
-                probe.load()
-
-            os.replace(tmp_path, file_path)
-        except BaseException:
-            tmp_path.unlink(missing_ok=True)
-            raise
-
-        # Set proper file permissions after saving
-        ensure_file_permissions(file_path, get_assets_file_mode())
-
         self.logger.debug(f"Downloaded logo to {file_path}")
     
     def _create_placeholder_logo(self, team_abbr: str, 

src/display_controller.py

@@ -207,6 +207,12 @@ class DisplayController:
         # _poll_on_demand_requests. None means "never polled", so the first
         # call always goes through.
         self._last_on_demand_poll: Optional[float] = None
+        # Monotonic stamp of the last _service_pending_changes pass; same
+        # "None means never" convention as _last_on_demand_poll.
+        self._last_pending_service: Optional[float] = None
+        # A brightness set_brightness() refused, so the periodic service pass
+        # doesn't retry (and log) the same failure several times a second.
+        self._failed_brightness_target: Optional[int] = None
         self.on_demand_active = False
         self.on_demand_mode: Optional[str] = None
         self.on_demand_modes: List[str] = []  # All modes for the on-demand plugin
@@ -586,10 +592,22 @@ class DisplayController:
         Returns:
             True if Vegas should yield control, False to continue
         """
+        # A Vegas iteration runs for up to max_cycle_duration (240s by
+        # default) without returning to the main loop, and this is the only
+        # code of ours it calls while it does. Without servicing here, an
+        # on-demand request was never even read until the iteration ended --
+        # on_demand_active below is only set by that read -- and a saved
+        # brightness or a schedule boundary waited just as long.
+        self._service_pending_changes()
+
         # Check for pending on-demand request
         if self.on_demand_active:
             return True
 
+        # Scheduled off mid-iteration: hand back so the main loop blanks it.
+        if not self.is_display_active:
+            return True
+
         # Check for wifi status that needs display
         if self._check_wifi_status_message():
             return True
@@ -1009,12 +1027,22 @@ class DisplayController:
             self.sync_manager.send_frame(follower_frame)
 
     def _sleep_with_plugin_updates(self, duration: float, tick_interval: float = 1.0):
-        """Sleep while continuing to service plugin update schedules."""
+        """Sleep while continuing to service plugin update schedules.
+
+        Also services pending changes (see _service_pending_changes), and
+        returns early when one of them changes what the panel should show --
+        an on-demand start or stop, or the display schedule turning the panel
+        on or off -- so the caller can act on it instead of finishing a dwell
+        that could be a minute long (sixty seconds while scheduled off).
+        """
         if duration <= 0:
             return
 
         end_time = time.time() + duration
-        tick_interval = max(0.001, tick_interval)
+        tick_interval = max(0.001, min(tick_interval, self.PENDING_CHANGES_INTERVAL))
+        mode = self.current_display_mode
+        display_active = self.is_display_active
+        on_demand = self.on_demand_active
 
         while True:
             remaining = end_time - time.time()
@@ -1024,6 +1052,11 @@ class DisplayController:
             sleep_time = min(tick_interval, remaining)
             time.sleep(sleep_time)
             self._tick_plugin_updates()
+            self._service_pending_changes()
+            if (self.current_display_mode != mode
+                    or self.is_display_active != display_active
+                    or self.on_demand_active != on_demand):
+                break
 
     def _get_display_duration(self, mode_key):
         """Seconds to show a mode: the Rotation & Durations page's value for it
@@ -1220,6 +1253,83 @@ class DisplayController:
     #: perceptible, and it cuts the read rate by 30x.
     ON_DEMAND_POLL_INTERVAL = 0.25
 
+    #: Shortest gap between _service_pending_changes passes. The same floor as
+    #: the mailbox poll, since that read is the only real cost in the pass:
+    #: the schedule checks are gated to once per clock minute and the rest is
+    #: attribute compares. Callers run at frame rate, so between passes the
+    #: whole cost is one monotonic-clock compare.
+    PENDING_CHANGES_INTERVAL = ON_DEMAND_POLL_INTERVAL
+
+    def _service_pending_changes(self) -> None:
+        """Apply changes made elsewhere while the display thread is busy.
+
+        The main loop applies on-demand requests, the display on/off schedule
+        and brightness (a saved display.hardware.brightness, or a dim-schedule
+        transition) once per pass -- that is, once per screen. A screen can
+        dwell a minute and a Vegas iteration four, so those waited just as
+        long: an on-demand request sat unread for up to 240s, and a brightness
+        saved and reverted within one screen never reached the panel at all.
+
+        So the places the display thread spends long stretches -- the dwell
+        sleep, the per-screen render loops and Vegas's interrupt check -- call
+        this. It is throttled to PENDING_CHANGES_INTERVAL, runs on the display
+        thread (set_brightness must not be called from the config watcher),
+        and does what the main loop does, in the same order. Callers decide
+        what to do about the result from the state it leaves behind
+        (on_demand_active, current_display_mode, is_display_active).
+        """
+        now = time.monotonic()
+        last = self._last_pending_service
+        if last is not None and now - last < self.PENDING_CHANGES_INTERVAL:
+            return
+        self._last_pending_service = now
+
+        try:
+            self._poll_on_demand_requests()
+            self._check_on_demand_expiration()
+            self._evaluate_schedule()
+            self._apply_brightness_target(repaint=True)
+        except Exception:  # pylint: disable=broad-except
+            # Called from inside Vegas and the render loops; a failure here
+            # must not take the display loop down with it.
+            logger.exception("Error servicing pending display changes")
+
+    def _evaluate_schedule(self) -> None:
+        """Re-check the on/off schedule, letting an on-demand session override it."""
+        self._check_schedule()
+        if self.on_demand_active and not self.is_display_active:
+            if not self.on_demand_schedule_override:
+                logger.info("On-demand override keeping display active during scheduled downtime")
+            self.on_demand_schedule_override = True
+            self.is_display_active = True
+        elif not self.on_demand_active and self.on_demand_schedule_override:
+            self.on_demand_schedule_override = False
+
+    def _apply_brightness_target(self, repaint: bool = False) -> None:
+        """Push the brightness the config and dim schedule call for, if it changed.
+
+        Args:
+            repaint: Re-push the current frame afterwards. The panel only shows
+                a new brightness from the next frame pushed; the main loop is
+                about to render one, but a dwell or a static screen may not
+                push again for a minute.
+        """
+        if not self.is_display_active:
+            return
+        target = self._check_dim_schedule()
+        if target == self.current_brightness:
+            self._failed_brightness_target = None
+            return
+        if target == self._failed_brightness_target:
+            return
+        if self.display_manager.set_brightness(target):
+            self.current_brightness = target
+            self._failed_brightness_target = None
+            if repaint:
+                self.display_manager.update_display()
+        else:
+            self._failed_brightness_target = target
+
     def _select_startup_plugins(self, discovered_plugins: List[str],
                                 on_demand_config: Optional[Dict[str, Any]]) -> List[str]:
         """Which plugins to load at startup, restoring on-demand state if any.
@@ -1850,21 +1960,11 @@ class DisplayController:
                     self._log_memory_stats_if_due()
 
                 # Check the schedule
-                self._check_schedule()
+                self._evaluate_schedule()
-                if self.on_demand_active and not self.is_display_active:
-                    if not self.on_demand_schedule_override:
-                        logger.info("On-demand override keeping display active during scheduled downtime")
-                    self.on_demand_schedule_override = True
-                    self.is_display_active = True
-                elif not self.on_demand_active and self.on_demand_schedule_override:
-                    self.on_demand_schedule_override = False
 
-                # Check dim schedule and apply brightness (only when display is active)
+                # Check dim schedule and apply brightness (only when display
-                if self.is_display_active:
+                # is active). No repaint: this screen's first frame pushes it.
-                    target_brightness = self._check_dim_schedule()
+                self._apply_brightness_target()
-                    if target_brightness != self.current_brightness:
-                        if self.display_manager.set_brightness(target_brightness):
-                            self.current_brightness = target_brightness
 
                 if not self.is_display_active:
                     # Clear display when schedule makes it inactive to ensure blank screen
@@ -2015,6 +2115,10 @@ class DisplayController:
                             else:
                                 # Vegas was interrupted (live priority), fall through to normal handling
                                 logger.debug("Vegas mode interrupted, falling back to normal rotation")
+                                if not self.is_display_active:
+                                    # Scheduled off mid-iteration: blank the
+                                    # panel now rather than render a screen.
+                                    continue
                         except Exception:
                             logger.exception("Vegas mode error")
                             # Fall through to normal rotation on error
@@ -2478,8 +2582,8 @@ class DisplayController:
                                 self._send_follower_frame(manager_to_display)
 
                                 self._tick_plugin_updates()
-                                self._poll_on_demand_requests()
+                                # Throttled: one clock compare between passes.
-                                self._check_on_demand_expiration()
+                                self._service_pending_changes()
 
                                 # Pace to the frame deadline rather than sleeping a flat
                                 # interval on top of the work. display() has already
@@ -2497,7 +2601,8 @@ class DisplayController:
                                 # update threads and the web UI are not starved of the GIL.
                                 time.sleep(_remaining if _remaining > 0 else 0.001)
 
-                                if self.current_display_mode != active_mode:
+                                if (self.current_display_mode != active_mode
+                                        or not self.is_display_active):
                                     logger.debug("Mode changed during high-FPS loop, breaking early")
                                     break
 
@@ -2575,9 +2680,9 @@ class DisplayController:
                                 # Multi-display sync: send follower frame after each render
                                 self._send_follower_frame(manager_to_display)
 
-                                self._poll_on_demand_requests()
+                                self._service_pending_changes()
-                                self._check_on_demand_expiration()
+                                if (self.current_display_mode != active_mode
-                                if self.current_display_mode != active_mode:
+                                        or not self.is_display_active):
                                     logger.info("Mode changed during display loop from %s to %s, breaking early", active_mode, self.current_display_mode)
                                     break
 
@@ -2604,7 +2709,10 @@ class DisplayController:
                         # Removing it again will silently reintroduce both issues. _activate_on_demand
                         # already sets force_change=True and clears the display, so the next loop
                         # iteration renders the new mode immediately.
-                        if self.current_display_mode != active_mode:
+                        # Likewise if the schedule turned the display off
+                        # mid-screen: the next iteration blanks it.
+                        if (self.current_display_mode != active_mode
+                                or not self.is_display_active):
                             continue
 
                         # Ensure we honour minimum duration when not dynamic and loop ended early
@@ -2652,7 +2760,15 @@ class DisplayController:
                     else:
                         # For non-plugin modes, use the original behavior
                         self._sleep_with_plugin_updates(max_duration)
-                
+
+                # The dwell sleeps above return early when a pending change
+                # (on-demand started or stopped, display scheduled off) has
+                # already decided what comes next; rotating now would skip it
+                # -- an on-demand start would advance past the requested mode.
+                if (self.current_display_mode != active_mode
+                        or not self.is_display_active):
+                    continue
+
                 # Move to next mode
                 if self.on_demand_active:
                     # Guard against empty on_demand_modes to prevent ZeroDivisionError

src/logo_downloader.py

@@ -7,17 +7,21 @@ with special support for FCS teams and other NCAA divisions.
 
 import os
 import re
+import tempfile
+import threading
 import time
 import logging
 import requests
 import json
 from typing import Dict, List, Optional, Tuple
 from pathlib import Path
-from PIL import Image, ImageDraw, ImageFont
+from PIL import Image, ImageDraw, ImageFont, UnidentifiedImageError
 from src.common.font_layout import load_truetype
 from PIL.PngImagePlugin import PngInfo
 from requests.adapters import HTTPAdapter
 from urllib3.util.retry import Retry
+from src.common.api_helper import DEFAULT_HTTP_HEADERS
+from src.common.logo_helper import MAX_LOGO_BYTES
 from src.common.permission_utils import (
     ensure_directory_permissions,
     ensure_file_permissions,
@@ -27,6 +31,142 @@ from src.common.permission_utils import (
 
 logger = logging.getLogger(__name__)
 
+#: Accept header for logo image requests (the JSON default is for the API).
+LOGO_ACCEPT = 'image/png,image/*;q=0.8'
+
+
+def _is_image_content_type(content_type: str) -> bool:
+    """True for an ``image/*`` media type, ignoring parameters and case.
+
+    Only a cheap gate before the body is read; Pillow decoding the bytes is
+    what actually decides whether they are an image.
+    """
+    return content_type.split(';', 1)[0].strip().lower().startswith('image/')
+
+
+def _to_rgba(img: Image.Image) -> Image.Image:
+    """``img`` as RGBA, keeping its transparency.
+
+    One conversion covers every mode: Pillow folds a palette's or a
+    greyscale/RGB image's ``transparency`` entry into the alpha channel when
+    converting to RGBA, and an image without one gets an opaque alpha. Plugins
+    paste logos with the image as its own mask, so the alpha is the part that
+    has to survive.
+    """
+    return img.copy() if img.mode == 'RGBA' else img.convert('RGBA')
+
+
+def _publish(tmp_path: Path, filepath: Path) -> None:
+    """Give a finished temp file the asset mode, then move it into place.
+
+    ``mkstemp`` creates files 0600, so the mode is set before the rename: the
+    logo must never be visible under its real name unreadable to the web
+    service's user. ``os.replace`` within one directory is atomic, so a reader
+    sees the old file or the new one, never a half-written one.
+    """
+    ensure_file_permissions(tmp_path, get_assets_file_mode())
+    os.replace(tmp_path, filepath)
+
+
+def _temp_beside(filepath: Path) -> Tuple[int, Path]:
+    """A unique temp file in ``filepath``'s directory.
+
+    Unique rather than a fixed ``<name>.part`` because two plugins can ask for
+    the same logo at once; a shared name would let them interleave writes into
+    one file, or delete each other's partial. The same directory keeps
+    ``os.replace`` atomic.
+    """
+    fd, tmp_name = tempfile.mkstemp(
+        dir=str(filepath.parent), prefix=filepath.name + '.', suffix='.part')
+    return fd, Path(tmp_name)
+
+
+def save_png_atomically(image: Image.Image, filepath: Path,
+                        pnginfo: Optional[PngInfo] = None) -> None:
+    """Save ``image`` as a PNG at ``filepath`` without ever exposing a partial file.
+
+    Raises on failure (including PermissionError for an unwritable
+    directory), leaving any previous file at ``filepath`` untouched and no
+    temp file behind.
+    """
+    filepath = Path(filepath)
+    fd, tmp_path = _temp_beside(filepath)
+    try:
+        with os.fdopen(fd, 'wb') as f:
+            if pnginfo is not None:
+                image.save(f, 'PNG', pnginfo=pnginfo)
+            else:
+                image.save(f, 'PNG')
+        _publish(tmp_path, filepath)
+    except BaseException:
+        tmp_path.unlink(missing_ok=True)
+        raise
+
+
+def fetch_logo(session: requests.Session, url: str, filepath: Path, *,
+               headers: Optional[Dict[str, str]] = None, timeout: float = 30,
+               max_bytes: Optional[int] = None) -> None:
+    """Download the image at ``url`` and save it at ``filepath`` as an RGBA PNG.
+
+    The one hardened logo download; ``LogoDownloader.download_logo`` and
+    ``LogoHelper._download_logo`` both go through it. A logo URL is remote
+    input, and whatever lands at ``filepath`` is cached and loaded on every
+    later frame, so nothing is written there until the bytes have been
+    size-checked and decoded:
+
+    - the response must be ``image/*`` and is streamed, counted as it
+      arrives, and abandoned past ``max_bytes`` (``MAX_LOGO_BYTES`` by
+      default) -- ``response.content`` would buffer a body that never ends
+      before any check could run;
+    - the bytes go to a unique temp file beside ``filepath`` and must decode
+      with Pillow (which also enforces its decompression-bomb limit);
+    - the image is converted to RGBA once, rewritten as PNG, and moved into
+      place atomically.
+
+    Raises on any failure, with no temp file left and any previous file at
+    ``filepath`` intact. The caller creates the directory.
+    """
+    if max_bytes is None:
+        max_bytes = MAX_LOGO_BYTES
+    filepath = Path(filepath)
+    fd, tmp_path = _temp_beside(filepath)
+    try:
+        # fdopen outermost so the descriptor is adopted and closed even when
+        # the request itself raises.
+        with os.fdopen(fd, 'wb') as f:
+            with session.get(url, headers=headers, timeout=timeout,
+                             stream=True) as response:
+                response.raise_for_status()
+                content_type = response.headers.get('content-type') or ''
+                if not _is_image_content_type(content_type):
+                    raise ValueError(
+                        f"Logo at {url} is not an image "
+                        f"(content-type {content_type!r}); not saved")
+                received = 0
+                for chunk in response.iter_content(chunk_size=64 * 1024):
+                    if not chunk:
+                        continue
+                    received += len(chunk)
+                    if received > max_bytes:
+                        raise ValueError(
+                            f"Logo at {url} exceeds the "
+                            f"{max_bytes}-byte limit; not saved")
+                    f.write(chunk)
+
+        # UnidentifiedImageError (an OSError) for bytes that are not an
+        # image, DecompressionBombError past Pillow's pixel limit, OSError for
+        # a truncated one.
+        with Image.open(tmp_path) as img:
+            img.load()
+            rgba = _to_rgba(img)
+        with open(tmp_path, 'wb') as f:
+            rgba.save(f, 'PNG')
+        _publish(tmp_path, filepath)
+    except BaseException:
+        tmp_path.unlink(missing_ok=True)
+        raise
+
+
 #: PNG text key stamped into a generated placeholder so a later run can tell it
 #: apart from a real logo that happens to be small.
 PLACEHOLDER_MARKER = "ledmatrix_placeholder"
@@ -199,14 +339,8 @@ class LogoDownloader:
         self.session.mount("https://", adapter)
         self.session.mount("http://", adapter)
         
-        # Set up headers
+        # Core's shared API headers; a plain dict so callers may adjust theirs.
-        self.headers = {
+        self.headers = dict(DEFAULT_HTTP_HEADERS)
-            'User-Agent': 'LEDMatrix/1.0 (https://github.com/yourusername/LEDMatrix; contact@example.com)',
-            'Accept': 'application/json',
-            'Accept-Language': 'en-US,en;q=0.9',
-            'Accept-Encoding': 'gzip, deflate, br',
-            'Connection': 'keep-alive'
-        }
     
     @staticmethod
     def normalize_abbreviation(abbreviation: str) -> str:
@@ -301,50 +435,19 @@ class LogoDownloader:
             return False
     
     def download_logo(self, logo_url: str, filepath: Path, team_abbreviation: str) -> bool:
-        """Download a single logo from URL and save to filepath."""
+        """Download a single logo from URL and save it to filepath as an RGBA PNG.
+
+        Returns False (and logs why) on any failure; see ``fetch_logo`` for
+        the guarantees -- in particular a failure never leaves a partial file,
+        and never replaces a logo already at ``filepath``.
+        """
+        filepath = Path(filepath)
         try:
-            response = self.session.get(logo_url, headers=self.headers, timeout=self.request_timeout)
+            fetch_logo(self.session, logo_url, filepath,
-            response.raise_for_status()
+                       headers={**self.headers, 'Accept': LOGO_ACCEPT},
-            
+                       timeout=self.request_timeout)
-            # Verify it's actually an image
+            logger.info(f"Successfully downloaded and converted logo for {team_abbreviation} -> {filepath.name}")
-            content_type = response.headers.get('content-type', '').lower()
+            return True
-            if not any(img_type in content_type for img_type in ['image/png', 'image/jpeg', 'image/jpg', 'image/gif']):
-                logger.warning(f"Downloaded content for {team_abbreviation} is not an image: {content_type}")
-                return False
-            
-            with open(filepath, 'wb') as f:
-                f.write(response.content)
-            
-            # Verify and convert the downloaded image to RGBA format
-            try:
-                with Image.open(filepath) as img:
-                    # Convert to RGBA to avoid PIL warnings about palette images with transparency
-                    if img.mode in ('P', 'LA', 'L'):
-                        # Convert palette or grayscale images to RGBA
-                        img = img.convert('RGBA')
-                    elif img.mode == 'RGB':
-                        # Convert RGB to RGBA (add alpha channel)
-                        img = img.convert('RGBA')
-                    elif img.mode != 'RGBA':
-                        # For any other mode, convert to RGBA
-                        img = img.convert('RGBA')
-                    
-                    # Save the converted image
-                    img.save(filepath, 'PNG')
-                
-                # Set proper file permissions after saving
-                ensure_file_permissions(filepath, get_assets_file_mode())
-                
-                logger.info(f"Successfully downloaded and converted logo for {team_abbreviation} -> {filepath.name}")
-                return True
-            except Exception as e:
-                logger.error(f"Downloaded file for {team_abbreviation} is not a valid image or conversion failed: {e}")
-                try:
-                    os.remove(filepath)  # Remove invalid file
-                except OSError:
-                    pass
-                return False
-            
         except PermissionError as e:
             logger.error(f"Permission denied downloading logo for {team_abbreviation}: {e}")
             logger.error("Please run: sudo ./scripts/fix_perms/fix_assets_permissions.sh")
@@ -352,10 +455,13 @@ class LogoDownloader:
         except requests.exceptions.RequestException as e:
             logger.error(f"Failed to download logo for {team_abbreviation}: {e}")
             return False
+        except (ValueError, UnidentifiedImageError, Image.DecompressionBombError) as e:
+            logger.error(f"Rejected downloaded logo for {team_abbreviation}: {e}")
+            return False
         except Exception as e:
             logger.error(f"Unexpected error downloading logo for {team_abbreviation}: {e}")
             return False
-    
+
     # Allowlist for the league_code segment interpolated into ESPN API URLs
     _SAFE_LEAGUE_CODE_RE = re.compile(r'^[a-z0-9_-]+$')
 
@@ -728,20 +834,7 @@ class LogoDownloader:
             
             filename = f"{self.normalize_abbreviation(team_abbreviation)}.png"
             filepath = Path(logo_dir) / filename
-            
+
-            # Check if we can write to the directory
-            try:
-                # Test write permissions by creating a temporary file
-                test_file = filepath.parent / "test_write.tmp"
-                test_file.touch()
-                test_file.unlink()  # Remove the test file
-            except PermissionError:
-                logger.error(f"Permission denied: Cannot write to directory {logo_dir}")
-                return False
-            except Exception as e:
-                logger.error(f"Directory access error for {logo_dir}: {e}")
-                return False
-            
             # Create a simple placeholder logo
             logo = Image.new('RGBA', (64, 64), (100, 100, 100, 255))  # Gray background
             draw = ImageDraw.Draw(logo)
@@ -774,14 +867,16 @@ class LogoDownloader:
             # proof the logo was fetched.
             metadata = PngInfo()
             metadata.add_text(PLACEHOLDER_MARKER, str(time.time()))
-            logo.save(filepath, "PNG", pnginfo=metadata)
+            # Atomic, and it sets the asset mode; an unwritable directory
-
+            # surfaces here as PermissionError.
-            # Set proper file permissions after saving
+            save_png_atomically(logo, filepath, pnginfo=metadata)
-            ensure_file_permissions(filepath, get_assets_file_mode())
 
             logger.info(f"Created placeholder logo for {team_abbreviation} at {filepath}")
             return True
-            
+
+        except PermissionError as e:
+            logger.error(f"Permission denied: Cannot write placeholder logo to {logo_dir}: {e}")
+            return False
         except Exception as e:
             logger.error(f"Failed to create placeholder logo for {team_abbreviation}: {e}")
             return False
@@ -837,6 +932,31 @@ def get_soccer_league_key(league_code: str) -> str:
     return f"soccer_{league_code}"
 
 
+_thread_state = threading.local()
+
+
+def shared_downloader() -> LogoDownloader:
+    """The calling thread's reusable LogoDownloader.
+
+    ``download_missing_logo`` used to build a new downloader -- a new
+    ``requests.Session``, retry adapter and connection pool -- for every logo.
+    Reusing one keeps connections to ESPN's CDN alive between logos.
+
+    One per thread rather than one behind a lock: ``requests.Session`` is not
+    documented as safe for concurrent use, and plugins download on worker
+    threads (football-scoreboard runs a small pool precisely so downloads
+    overlap). A lock would serialise every plugin's downloads behind the
+    slowest one -- up to 30s per attempt, with retries. Pool threads persist,
+    so each still reuses its own session; a thread's downloader goes with the
+    thread.
+    """
+    downloader = getattr(_thread_state, 'downloader', None)
+    if downloader is None:
+        downloader = LogoDownloader()
+        _thread_state.downloader = downloader
+    return downloader
+
+
 # Convenience function for easy integration
 def download_missing_logo(league: str, team_id: str, team_abbreviation: str, logo_path: Path, logo_url: str | None = None, create_placeholder: bool = True) -> bool:
     """
@@ -852,8 +972,8 @@ def download_missing_logo(league: str, team_id: str, team_abbreviation: str, log
     Returns:
         True if logo exists or was successfully downloaded, False otherwise
     """
-    downloader = LogoDownloader()
+    downloader = shared_downloader()
-    
+
     # Use the directory from the logo_path parameter (respects config settings)
     logo_path = Path(logo_path)
     if not logo_path.is_absolute():
@@ -920,5 +1040,5 @@ def download_all_logos_for_league(league: str, force_download: bool = False) ->
     Returns:
         Tuple of (downloaded_count, failed_count)
     """
-    downloader = LogoDownloader()
+    downloader = shared_downloader()
     return downloader.download_missing_logos_for_league(league, force_download)

test/test_display_pending_changes.py

@@ -0,0 +1,592 @@
+"""Changes made from the web UI must reach the panel while a screen is showing.
+
+The main loop applies on-demand requests, the display schedule and brightness
+once per pass -- once per screen. Screens are long: a dwell can be a minute and
+a Vegas iteration runs for vegas_scroll.max_cycle_duration (240s here). On a
+real Pi on 2026-09-23:
+
+  * an on-demand request posted at 10:54:27 was activated at 10:57:24, when the
+    Vegas iteration it arrived during finally ended -- nothing read the mailbox
+    in between, because _check_vegas_interrupt only looked at a flag that the
+    main-loop read sets;
+  * two brightness saves 12s apart inside one 30s screen never showed at all.
+
+_service_pending_changes is the fix: a throttled pass the dwell sleep, the
+render loops and the Vegas interrupt check all call. These tests drive those
+long stretches on a fake clock and check a change lands within one throttle
+interval -- and that the throttle holds, since the callers run at frame rate.
+"""
+
+import threading
+import types
+from datetime import datetime, timedelta
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from src.vegas_mode.config import VegasModeConfig
+from src.vegas_mode.coordinator import VegasModeCoordinator
+
+VEGAS_ITERATION_SECONDS = 240
+REQUEST_KEY = 'display_on_demand_request'
+
+
+class FakeClock:
+    """A clock that only moves when the code under test sleeps.
+
+    Installed as the ``time`` module of display_controller and the Vegas
+    coordinator only -- patching the real module would also speed up every
+    background thread in the process.
+    """
+
+    def __init__(self, start=10_000.0):
+        self.t = start
+        self._events = []
+
+    def now(self):
+        return self.t
+
+    def sleep(self, seconds):
+        # Never zero, so a loop that sleeps "the rest of the frame" still
+        # advances when its fake frame took no time.
+        self.t += max(seconds, 0.0005)
+        while self._events and self._events[0][0] <= self.t:
+            _, fn = self._events.pop(0)
+            fn()
+
+    def after(self, seconds, fn):
+        """Run fn once the clock is `seconds` past now."""
+        self._events.append((self.t + seconds, fn))
+        self._events.sort(key=lambda e: e[0])
+
+    def module(self):
+        return types.SimpleNamespace(time=self.now, monotonic=self.now,
+                                     perf_counter=self.now, sleep=self.sleep)
+
+
+@pytest.fixture
+def clock(monkeypatch):
+    c = FakeClock()
+    fake_time = c.module()
+    monkeypatch.setattr('src.display_controller.time', fake_time)
+    monkeypatch.setattr('src.vegas_mode.coordinator.time', fake_time)
+    return c
+
+
+@pytest.fixture
+def controller(test_display_controller, clock):
+    """A controller at rest: no schedule, full brightness, empty mailbox."""
+    c = test_display_controller
+    c._refresh_config_cache({'display': {'hardware': {'brightness': 90}}})
+    c.current_brightness = 90
+    c.is_display_active = True
+    c._check_wifi_status_message = MagicMock(return_value=None)
+
+    c.mailbox = {}  # what the web process has written
+
+    def cache_get(key, *args, **kwargs):
+        if key == REQUEST_KEY:
+            return c.mailbox.get('request')
+        return None
+
+    def cache_delete(key):
+        if key == REQUEST_KEY:
+            c.mailbox.pop('request', None)
+
+    c.cache_manager.get = MagicMock(side_effect=cache_get)
+    c.cache_manager.delete = MagicMock(side_effect=cache_delete)
+    c.cache_manager.set = MagicMock()
+    c.display_manager.set_brightness = MagicMock(return_value=True)
+    c.display_manager.update_display = MagicMock()
+
+    # Two loaded plugins: the rotation is on one, on-demand can ask for either.
+    for mode in ('clock', 'weather'):
+        c.plugin_display_modes[mode] = [mode]
+        c.plugin_modes[mode] = MagicMock(spec=[])
+        c.mode_to_plugin_id[mode] = mode
+    c.available_modes = ['clock', 'weather']
+    c.current_mode_index = 0
+    c.current_display_mode = 'clock'
+    return c
+
+
+def post_request(controller, request_id='r1', mode='clock'):
+    controller.mailbox['request'] = {
+        'request_id': request_id, 'action': 'start',
+        'plugin_id': mode, 'mode': mode,
+    }
+
+
+def save_brightness(controller, brightness):
+    """What the config watcher thread does when the web UI saves."""
+    controller._controller_config_change(
+        controller.config,
+        {'display': {'hardware': {'brightness': brightness}}})
+
+
+def mailbox_reads(controller):
+    return sum(1 for call in controller.cache_manager.get.call_args_list
+               if call.args and call.args[0] == REQUEST_KEY)
+
+
+def vegas_coordinator(controller):
+    """A coordinator that runs real run_iteration() over a stub renderer.
+
+    Wired to the controller's interrupt checker the way _initialize_vegas_mode
+    wires it (every 10 frames).
+    """
+    coord = VegasModeCoordinator.__new__(VegasModeCoordinator)
+    coord.vegas_config = VegasModeConfig.from_config({'display': {'vegas_scroll': {
+        'enabled': True, 'max_cycle_duration': VEGAS_ITERATION_SECONDS}}})
+    assert coord.vegas_config.continuous_scroll
+    coord.render_pipeline = MagicMock()
+    coord.stream_manager = MagicMock()
+    coord.display_manager = controller.display_manager
+    coord.stats = {'cycles_completed': 0, 'interruptions': 0}
+    coord._state_lock = threading.Lock()
+    coord._is_active = True
+    coord._is_paused = False
+    coord._should_stop = False
+    coord._fps_last_health_log = 0.0
+    coord._fps_was_degraded = False
+    coord._live_priority_check = None
+    coord._live_priority_active = False
+    coord._update_callback = None
+    coord._update_tick_running = False
+    coord.sync_manager = None
+    coord._update_static_mode_plugins = lambda: None
+    coord._check_static_plugin_trigger = lambda: None
+    coord.frames = 0
+
+    def run_frame():
+        coord.frames += 1
+        return True
+
+    coord.run_frame = run_frame
+    coord.set_interrupt_checker(controller._check_vegas_interrupt, check_interval=10)
+    return coord
+
+
+def frame_budget(coord):
+    """Longest a change can wait for the next interrupt check."""
+    return coord._interrupt_check_interval * coord.vegas_config.get_frame_interval()
+
+
+class TestOnDemandDuringVegas:
+    def test_a_request_mid_iteration_ends_the_iteration_promptly(self, controller, clock):
+        coord = vegas_coordinator(controller)
+        start = clock.t
+        posted = {}
+
+        def post():
+            posted['at'] = clock.t
+            post_request(controller, mode='weather')
+
+        clock.after(30, post)
+        completed = coord.run_iteration()
+        latency = clock.t - posted['at']
+
+        assert completed is False, "Vegas ran the whole iteration past the request"
+        assert controller.on_demand_active
+        assert controller.current_display_mode == 'weather'
+        assert latency <= controller.PENDING_CHANGES_INTERVAL + frame_budget(coord) + 0.01, (
+            f"request took {latency:.2f}s to interrupt Vegas")
+        assert clock.t - start < VEGAS_ITERATION_SECONDS
+
+    def test_the_interrupt_checker_answers_within_one_interval(self, controller, clock):
+        controller._service_pending_changes()  # the main loop's last pass
+        post_request(controller)
+        waited = 0.0
+        step = 0.01
+        while not controller._check_vegas_interrupt():
+            clock.t += step
+            waited += step
+            assert waited <= controller.PENDING_CHANGES_INTERVAL + step, (
+                "interrupt checker never saw the request")
+        assert controller.on_demand_active
+
+    def test_an_empty_mailbox_lets_the_iteration_run_out(self, controller, clock):
+        coord = vegas_coordinator(controller)
+        assert coord.run_iteration() is True
+        assert not controller.on_demand_active
+        # And the read is throttled: at most one per interval, not per check.
+        max_reads = VEGAS_ITERATION_SECONDS / controller.PENDING_CHANGES_INTERVAL + 1
+        assert 0 < mailbox_reads(controller) <= max_reads
+        checks = coord.frames // coord._interrupt_check_interval
+        assert mailbox_reads(controller) < checks / 2
+
+
+class TestBrightnessIsAppliedMidScreen:
+    def _applied_at(self, controller, clock, brightness):
+        """Clock time set_brightness(brightness) was first called, or None."""
+        return controller.applied.get(brightness)
+
+    def _record_brightness(self, controller, clock):
+        controller.applied = {}
+
+        def set_brightness(value):
+            controller.applied.setdefault(value, clock.t)
+            return True
+
+        controller.display_manager.set_brightness = MagicMock(side_effect=set_brightness)
+
+    def test_during_a_long_dwell(self, controller, clock):
+        """The observed failure: two saves 12s apart inside one screen."""
+        self._record_brightness(controller, clock)
+        saves = {}
+
+        def save(value):
+            saves[value] = clock.t
+            save_brightness(controller, value)
+
+        clock.after(5, lambda: save(40))
+        clock.after(17, lambda: save(90))
+        controller._sleep_with_plugin_updates(30)
+
+        interval = controller.PENDING_CHANGES_INTERVAL
+        assert 40 in controller.applied, "brightness 40 never reached the panel"
+        assert controller.applied[40] - saves[40] <= interval + 0.01
+        assert controller.applied[90] - saves[90] <= interval + 0.01
+        assert controller.current_brightness == 90
+
+    def test_the_frame_is_repushed_so_the_change_shows(self, controller, clock):
+        clock.after(1, lambda: save_brightness(controller, 40))
+        controller._sleep_with_plugin_updates(5)
+        calls = controller.display_manager.method_calls
+        names = [c[0] for c in calls]
+        assert 'set_brightness' in names
+        assert 'update_display' in names[names.index('set_brightness'):], (
+            "nothing pushed a frame after the brightness change")
+
+    def test_during_a_vegas_iteration(self, controller, clock):
+        self._record_brightness(controller, clock)
+        coord = vegas_coordinator(controller)
+        saved = {}
+
+        def save():
+            saved['at'] = clock.t
+            save_brightness(controller, 25)
+
+        clock.after(60, save)
+        assert coord.run_iteration() is True  # brightness does not end the scroll
+        assert 25 in controller.applied, "brightness waited for the iteration to end"
+        assert controller.applied[25] - saved['at'] <= (
+            controller.PENDING_CHANGES_INTERVAL + frame_budget(coord) + 0.01)
+
+    def test_a_dim_schedule_transition_mid_dwell(self, controller, clock):
+        self._record_brightness(controller, clock)
+        controller._refresh_config_cache({
+            'display': {'hardware': {'brightness': 90}},
+            'dim_schedule': {'enabled': True, 'start_time': '20:00',
+                             'end_time': '07:00', 'dim_brightness': 20},
+        })
+        wall_start = datetime(2026, 9, 21, 19, 59, 30)
+        t0 = clock.t
+        with patch('src.display_controller.datetime') as mock_dt:
+            mock_dt.strptime = datetime.strptime
+            mock_dt.now.side_effect = lambda tz=None: wall_start + timedelta(seconds=clock.t - t0)
+            controller._sleep_with_plugin_updates(60)
+
+        assert 20 in controller.applied, "the dim period started mid-screen and was missed"
+        dimmed_at = t0 + 30  # 20:00:00
+        assert controller.applied[20] - dimmed_at <= controller.PENDING_CHANGES_INTERVAL + 0.01
+
+
+class TestThrottle:
+    def test_no_reads_or_brightness_calls_between_passes(self, controller, clock):
+        controller._service_pending_changes()
+        reads = mailbox_reads(controller)
+        save_brightness(controller, 40)
+        post_request(controller)
+        for _ in range(500):  # a few seconds of frames, all inside one interval
+            controller._service_pending_changes()
+            clock.t += controller.PENDING_CHANGES_INTERVAL / 1000
+        assert mailbox_reads(controller) == reads
+        controller.display_manager.set_brightness.assert_not_called()
+        assert not controller.on_demand_active
+
+        clock.t += controller.PENDING_CHANGES_INTERVAL
+        controller._service_pending_changes()
+        # The poll, plus the consume step's re-read of the request it acted on.
+        assert mailbox_reads(controller) > reads
+        controller.display_manager.set_brightness.assert_called_once_with(40)
+        assert controller.on_demand_active
+
+    def test_between_passes_it_does_no_work_at_all(self, controller, clock):
+        """The high-FPS and Vegas loops call this every frame."""
+        controller._service_pending_changes()
+        controller._poll_on_demand_requests = MagicMock()
+        controller._check_dim_schedule = MagicMock(return_value=90)
+        controller._check_schedule = MagicMock()
+        for _ in range(100):
+            controller._service_pending_changes()
+            controller._check_vegas_interrupt()
+        controller._poll_on_demand_requests.assert_not_called()
+        controller._check_dim_schedule.assert_not_called()
+        controller._check_schedule.assert_not_called()
+
+    def test_an_unchanged_brightness_is_not_re_sent(self, controller, clock):
+        for _ in range(20):
+            controller._service_pending_changes()
+            clock.t += controller.PENDING_CHANGES_INTERVAL
+        controller.display_manager.set_brightness.assert_not_called()
+
+    def test_a_refused_brightness_is_not_retried_every_pass(self, controller, clock):
+        controller.display_manager.set_brightness = MagicMock(return_value=False)
+        save_brightness(controller, 40)
+        for _ in range(20):
+            controller._service_pending_changes()
+            clock.t += controller.PENDING_CHANGES_INTERVAL
+        controller.display_manager.set_brightness.assert_called_once_with(40)
+        assert controller.current_brightness == 90
+        # A different target is still tried.
+        save_brightness(controller, 50)
+        controller._service_pending_changes()
+        controller.display_manager.set_brightness.assert_called_with(50)
+
+    def test_a_refused_brightness_is_tried_again_after_going_back(self, controller, clock):
+        controller.display_manager.set_brightness = MagicMock(return_value=False)
+        for value in (40, 90, 40):
+            save_brightness(controller, value)
+            controller._service_pending_changes()
+            clock.t += controller.PENDING_CHANGES_INTERVAL
+        assert controller.display_manager.set_brightness.call_count == 2
+
+
+class TestScheduleAndDwells:
+    def _schedule_until(self, controller, end_time):
+        controller._refresh_config_cache({
+            'display': {'hardware': {'brightness': 90}},
+            'schedule': {'enabled': True, 'start_time': '07:00', 'end_time': end_time},
+        })
+
+    def test_vegas_hands_back_when_the_display_is_scheduled_off(self, controller, clock):
+        self._schedule_until(controller, '22:59')
+        coord = vegas_coordinator(controller)
+        wall_start = datetime(2026, 9, 21, 22, 59, 0)
+        t0 = clock.t
+        with patch('src.display_controller.datetime') as mock_dt:
+            mock_dt.strptime = datetime.strptime
+            mock_dt.now.side_effect = lambda tz=None: wall_start + timedelta(seconds=clock.t - t0)
+            completed = coord.run_iteration()
+        assert completed is False
+        assert not controller.is_display_active
+        off_at = t0 + 60  # 23:00:00
+        assert clock.t - off_at <= controller.PENDING_CHANGES_INTERVAL + frame_budget(coord) + 0.01
+
+    def test_on_demand_wakes_a_scheduled_off_display_within_an_interval(self, controller, clock):
+        """The display-off branch sleeps 60s at a time between checks."""
+        controller.is_display_active = False
+        controller._evaluate_schedule = MagicMock()  # hold the schedule "off"
+        posted = {}
+
+        def post():
+            posted['at'] = clock.t
+            post_request(controller)
+
+        clock.after(3, post)
+        start = clock.t
+        controller._sleep_with_plugin_updates(60)
+        assert controller.on_demand_active
+        assert clock.t - start < 60, "the off-schedule sleep ran its full minute"
+        assert clock.t - posted['at'] <= controller.PENDING_CHANGES_INTERVAL + 0.01
+
+    def test_the_dwell_returns_early_on_an_on_demand_stop(self, controller, clock):
+        post_request(controller)
+        controller._service_pending_changes()
+        assert controller.on_demand_active
+        clock.t += controller.PENDING_CHANGES_INTERVAL
+        controller.mailbox['request'] = {'request_id': 'r2', 'action': 'stop'}
+        start = clock.t
+        controller._sleep_with_plugin_updates(30)
+        assert not controller.on_demand_active
+        assert clock.t - start <= controller.PENDING_CHANGES_INTERVAL + 0.01
+
+    def test_a_quiet_dwell_runs_its_full_length(self, controller, clock):
+        start = clock.t
+        controller._sleep_with_plugin_updates(30)
+        assert clock.t - start >= 30
+
+
+class _Plugin:
+    """A static (non-scrolling) plugin mode that records what was shown."""
+
+    needs_high_fps = False
+
+    def __init__(self, mode, plugin_id, shown, results=()):
+        self.mode = mode
+        self.plugin_id = plugin_id
+        self._shown = shown
+        self._results = iter(results)
+
+    def display(self, force_clear=False):
+        self._shown.append(self.mode)
+        if len(self._shown) > 6:
+            raise KeyboardInterrupt  # ends run(); it catches this and cleans up
+        return next(self._results, True)
+
+
+class TestRunLoopDoesNotSkipTheRequestedMode:
+    def test_on_demand_during_the_minimum_duration_sleep(self, controller, clock):
+        """A dwell sleep that ends early on an on-demand start must not rotate.
+
+        The first screen shows once, then reports no content, so run() sleeps
+        out the rest of its minimum duration. The request lands during that
+        sleep. Falling through to "move to next mode" advanced the new
+        on-demand rotation past the mode that was asked for.
+        """
+        c = controller
+        shown = []
+        c.plugin_modes.clear()
+        c.mode_to_plugin_id.clear()
+        c.plugin_display_modes.clear()
+        modes = {'clock': ('clock', [True, False]), 'news': ('news', []),
+                 'weather': ('weather', []), 'weather_hourly': ('weather', [])}
+        for mode, (pid, results) in modes.items():
+            c.plugin_modes[mode] = _Plugin(mode, pid, shown, results)
+            c.mode_to_plugin_id[mode] = pid
+            c.plugin_display_modes.setdefault(pid, []).append(mode)
+        c.available_modes = list(modes)
+        c.current_mode_index = 0
+        c._cleanup_expired_wifi_status = MagicMock()
+        c.config.setdefault('display', {})['display_durations'] = {'clock': 30}
+        c.plugin_manager.plugin_executor.execute_display.side_effect = (
+            lambda target, plugin_id, force_clear=False, display_mode=None, **kw:
+            target.display(force_clear=force_clear))
+        clock.after(10, lambda: post_request(c, mode='weather'))
+
+        c.run()
+
+        assert c.on_demand_modes[:2] == ['weather', 'weather_hourly']
+        assert shown[:2] == ['clock', 'clock']
+        assert shown[2] == 'weather', f"on-demand opened on {shown[2]}, not the requested mode"
+
+
+class _Stop(KeyboardInterrupt):
+    """Ends run(): it catches KeyboardInterrupt and cleans up."""
+
+
+class TestRunLoopBlanksWhenVegasHandsBack:
+    def test_scheduled_off_mid_iteration_blanks_instead_of_rendering(self, controller, clock):
+        c = controller
+        shown = []
+        c.plugin_modes['clock'] = _Plugin('clock', 'clock', shown)
+        c.plugin_modes['weather'] = _Plugin('weather', 'weather', shown)
+        c._cleanup_expired_wifi_status = MagicMock()
+        c._refresh_config_cache({
+            'display': {'hardware': {'brightness': 90}},
+            'schedule': {'enabled': True, 'start_time': '07:00', 'end_time': '22:59'},
+        })
+        c.vegas_coordinator = vegas_coordinator(c)
+        c.vegas_coordinator._pending_config_update = False
+
+        def stop():
+            raise _Stop()
+
+        wall_start = datetime(2026, 9, 21, 22, 59, 0)
+        t0 = clock.t
+        clock.after(90, stop)
+        with patch('src.display_controller.datetime') as mock_dt:
+            mock_dt.strptime = datetime.strptime
+            mock_dt.now.side_effect = lambda tz=None: wall_start + timedelta(seconds=clock.t - t0)
+            c.run()
+
+        assert c.vegas_coordinator.frames > 0  # Vegas was running first
+        assert not c.is_display_active
+        assert shown == [], f"rendered {shown} after the display was scheduled off"
+        c.display_manager.clear.assert_called()
+
+    @pytest.mark.parametrize('needs_high_fps', [True, False])
+    def test_a_screen_scheduled_off_midway_stops_rendering(self, controller, clock,
+                                                           needs_high_fps):
+        c = controller
+        shown_at = []
+        plugin = _Plugin('ticker', 'ticker', [])
+        plugin.needs_high_fps = needs_high_fps
+        plugin.display = lambda force_clear=False: shown_at.append(clock.t) or True
+        c.plugin_modes.clear()
+        c.mode_to_plugin_id.clear()
+        c.plugin_display_modes.clear()
+        c.plugin_modes['ticker'] = plugin
+        c.mode_to_plugin_id['ticker'] = 'ticker'
+        c.plugin_display_modes['ticker'] = ['ticker']
+        c.available_modes = ['ticker']
+        c.current_mode_index = 0
+        c._cleanup_expired_wifi_status = MagicMock()
+        c._refresh_config_cache({
+            'display': {'hardware': {'brightness': 90},
+                        'display_durations': {'ticker': 120}},
+            'schedule': {'enabled': True, 'start_time': '07:00', 'end_time': '22:59'},
+        })
+        c.plugin_manager.plugin_executor.execute_display.side_effect = (
+            lambda target, plugin_id, force_clear=False, display_mode=None, **kw:
+            target.display(force_clear=force_clear))
+
+        def stop():
+            raise _Stop()
+
+        wall_start = datetime(2026, 9, 21, 22, 59, 0)
+        t0 = clock.t
+        clock.after(150, stop)
+        with patch('src.display_controller.datetime') as mock_dt:
+            mock_dt.strptime = datetime.strptime
+            mock_dt.now.side_effect = lambda tz=None: wall_start + timedelta(seconds=clock.t - t0)
+            c.run()
+
+        off_at = t0 + 60  # 23:00:00, halfway through a 120s screen
+        assert shown_at and shown_at[0] < off_at
+        assert shown_at[-1] - off_at <= 1.0 + c.PENDING_CHANGES_INTERVAL, (
+            f"kept rendering {shown_at[-1] - off_at:.1f}s after the display was scheduled off")
+        assert not c.is_display_active
+
+
+class TestRunLoopAppliesBrightnessMidScreen:
+    """The render loops of run() itself, not just the helpers they call."""
+
+    def _run_screen(self, c, clock, needs_high_fps):
+        shown = []
+        plugin = _Plugin('ticker', 'ticker', shown)
+        plugin.needs_high_fps = needs_high_fps
+        plugin.display = lambda force_clear=False: shown.append('ticker') or True
+        c.plugin_modes.clear()
+        c.mode_to_plugin_id.clear()
+        c.plugin_display_modes.clear()
+        c.plugin_modes['ticker'] = plugin
+        c.mode_to_plugin_id['ticker'] = 'ticker'
+        c.plugin_display_modes['ticker'] = ['ticker']
+        c.available_modes = ['ticker']
+        c.current_mode_index = 0
+        c._cleanup_expired_wifi_status = MagicMock()
+        c.config.setdefault('display', {})['display_durations'] = {'ticker': 60}
+        c.plugin_manager.plugin_executor.execute_display.side_effect = (
+            lambda target, plugin_id, force_clear=False, display_mode=None, **kw:
+            target.display(force_clear=force_clear))
+        applied = {}
+
+        def set_brightness(value):
+            applied.setdefault(value, clock.t)
+            return True
+
+        c.display_manager.set_brightness = MagicMock(side_effect=set_brightness)
+        start = clock.t
+        clock.after(5, lambda: save_brightness(c, 30))
+
+        def stop():
+            raise _Stop()
+
+        clock.after(20, stop)
+        c.run()
+        return start, applied, shown
+
+    def test_a_scrolling_screen(self, controller, clock):
+        start, applied, shown = self._run_screen(controller, clock, needs_high_fps=True)
+        assert len(shown) > 100  # really was the high-FPS loop
+        assert 30 in applied, "brightness waited for the scrolling screen to end"
+        assert applied[30] - (start + 5) <= controller.PENDING_CHANGES_INTERVAL + 0.02
+
+    def test_a_static_screen(self, controller, clock):
+        start, applied, shown = self._run_screen(controller, clock, needs_high_fps=False)
+        assert len(shown) < 30  # really was the once-a-second loop
+        assert 30 in applied, "brightness waited for the static screen to end"
+        # This loop redraws once a second, and services changes after each redraw.
+        assert applied[30] - (start + 5) <= 1.0 + controller.PENDING_CHANGES_INTERVAL

test/test_http_headers.py

@@ -0,0 +1,80 @@
+"""One set of HTTP headers for core's ESPN/data requests.
+
+The logo downloader and the background data service each carried their own
+header dict with a placeholder User-Agent (``yourusername/LEDMatrix;
+contact@example.com``) -- the kind of nonconforming token ESPN began 403ing
+around 2026-08-04 -- and a hand-set ``Accept-Encoding: ... br`` although brotli
+is not installed, so a ``br`` body could not have been decoded.
+"""
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from src.common.api_helper import DEFAULT_HTTP_HEADERS, USER_AGENT, APIHelper
+
+
+def _lower_keys(headers):
+    return {k.lower(): v for k, v in headers.items()}
+
+
+class TestSharedHeaders:
+    def test_user_agent_names_the_project(self):
+        assert USER_AGENT == 'LEDMatrix/1.0 (+https://github.com/ChuckBuilds/LEDMatrix)'
+        assert DEFAULT_HTTP_HEADERS['User-Agent'] == USER_AGENT
+
+    def test_no_hand_set_accept_encoding(self):
+        assert 'accept-encoding' not in _lower_keys(DEFAULT_HTTP_HEADERS)
+
+    def test_is_read_only(self):
+        with pytest.raises(TypeError):
+            DEFAULT_HTTP_HEADERS['User-Agent'] = 'x'  # type: ignore[index]
+
+    def test_api_helper_sends_the_same_user_agent(self):
+        assert APIHelper().session.headers['User-Agent'] == USER_AGENT
+
+    def test_api_helper_does_not_hand_set_brotli(self):
+        assert 'br' not in APIHelper().session.headers.get('Accept-Encoding', '')
+
+    def test_logo_helper_sends_the_same_user_agent(self):
+        from src.common.logo_helper import LogoHelper
+        assert LogoHelper(display_width=64, display_height=32).session.headers['User-Agent'] == USER_AGENT
+
+
+class TestLogoDownloaderHeaders:
+    def test_uses_the_shared_headers(self):
+        from src.logo_downloader import LogoDownloader
+        headers = LogoDownloader().headers
+        assert headers['User-Agent'] == USER_AGENT
+        assert 'accept-encoding' not in _lower_keys(headers)
+        assert 'yourusername' not in str(headers)
+
+    def test_instance_headers_are_a_private_copy(self):
+        from src.logo_downloader import LogoDownloader
+        downloader = LogoDownloader()
+        downloader.headers['X-Test'] = '1'
+        assert 'X-Test' not in DEFAULT_HTTP_HEADERS
+        assert 'X-Test' not in LogoDownloader().headers
+
+    def test_logo_request_sends_the_user_agent_and_asks_for_an_image(self, tmp_path):
+        from src.logo_downloader import LogoDownloader
+        downloader = LogoDownloader()
+        downloader.session.get = MagicMock(side_effect=RuntimeError("stop"))
+        downloader.download_logo("http://x/a.png", tmp_path / "A.png", "A")
+        sent = _lower_keys(downloader.session.get.call_args.kwargs['headers'])
+        assert sent['user-agent'] == USER_AGENT
+        assert sent['accept'].startswith('image/')
+        assert 'accept-encoding' not in sent
+
+
+class TestBackgroundDataServiceHeaders:
+    def test_uses_the_shared_headers(self):
+        from src.background_data_service import BackgroundDataService
+        service = BackgroundDataService(MagicMock(), max_workers=1)
+        try:
+            headers = service.default_headers
+            assert headers['User-Agent'] == USER_AGENT
+            assert 'accept-encoding' not in _lower_keys(headers)
+            assert 'yourusername' not in str(headers)
+        finally:
+            service.shutdown(wait=False)

test/test_logo_downloader.py

@@ -7,16 +7,20 @@ ensure_logo_directory, and the download_missing_logo function path
 (with HTTP mocked).
 """
 
+import io
 import os
+import threading
 import time
 
 import pytest
+import requests
 from pathlib import Path
 from unittest.mock import patch, Mock, MagicMock
 
 from PIL import Image
 from PIL.PngImagePlugin import PngInfo
 
+import src.logo_downloader as logo_downloader_module
 from src.logo_downloader import (
     PLACEHOLDER_BG,
     PLACEHOLDER_MARKER,
@@ -351,3 +355,266 @@ class TestRefreshPlaceholderTimestamp:
 
     def test_missing_file_is_not_an_error(self, tmp_path):
         assert refresh_placeholder_timestamp(tmp_path / "nope.png") is False
+
+
+# ---------------------------------------------------------------------------
+# download_logo: the download the scoreboard plugins actually use
+#
+# It used to read response.content with no size cap, write straight to the
+# final path (so a failed or corrupt download could be left there and then be
+# cached as the logo), and build a fresh Session for every logo. It now goes
+# through fetch_logo, the hardened download LogoHelper also uses.
+# ---------------------------------------------------------------------------
+
+def _png(img: Image.Image) -> bytes:
+    buf = io.BytesIO()
+    img.save(buf, "PNG")
+    return buf.getvalue()
+
+
+def _stream(body: bytes, content_type: str = "image/png", chunk: int = 1024,
+            die_after: int | None = None):
+    """A streamed requests.Response stand-in.
+
+    ``die_after`` makes the transfer fail after that many bytes, the way a
+    reset connection does mid-body.
+    """
+    response = MagicMock()
+    response.__enter__.return_value = response
+    response.__exit__.return_value = False
+    response.raise_for_status = MagicMock()
+    response.headers = {"content-type": content_type}
+
+    def _iter_content(*_args, **_kwargs):
+        sent = 0
+        for i in range(0, len(body), chunk):
+            if die_after is not None and sent >= die_after:
+                raise requests.exceptions.ChunkedEncodingError("connection reset")
+            piece = body[i:i + chunk]
+            sent += len(piece)
+            yield piece
+
+    response.iter_content = _iter_content
+    return response
+
+
+@pytest.fixture
+def fresh_thread_state(monkeypatch):
+    """Each test gets its own per-thread downloader cache."""
+    monkeypatch.setattr(logo_downloader_module, "_thread_state", threading.local())
+
+
+@pytest.fixture
+def downloader():
+    return LogoDownloader()
+
+
+@pytest.fixture
+def old_logo(tmp_path):
+    """A logo already on disk that a failed re-download must not damage."""
+    path = tmp_path / "PHI.png"
+    Image.new("RGBA", (30, 30), (1, 2, 3, 255)).save(path)
+    return path, path.read_bytes()
+
+
+def _leftovers(directory: Path, keep: str | None = None):
+    return sorted(p.name for p in directory.iterdir() if p.name != keep)
+
+
+class TestDownloadLogoHardening:
+    def test_valid_logo_is_saved_as_rgba_png(self, downloader, tmp_path):
+        target = tmp_path / "PHI.png"
+        downloader.session.get = MagicMock(
+            return_value=_stream(_png(Image.new("RGB", (20, 10), (9, 8, 7)))))
+        assert downloader.download_logo("http://x/phi.png", target, "PHI") is True
+        with Image.open(target) as img:
+            assert img.format == "PNG" and img.mode == "RGBA"
+            assert img.getpixel((0, 0)) == (9, 8, 7, 255)
+        assert _leftovers(tmp_path, keep="PHI.png") == []
+        # Streamed, so the size cap applies before the body is buffered.
+        assert downloader.session.get.call_args.kwargs["stream"] is True
+
+    def test_oversized_response_is_rejected_and_leaves_no_file(
+            self, downloader, tmp_path, monkeypatch):
+        monkeypatch.setattr(logo_downloader_module, "MAX_LOGO_BYTES", 4096)
+        target = tmp_path / "BIG.png"
+        body = _png(Image.new("RGB", (8, 8))) + b"\x00" * 8192
+        downloader.session.get = MagicMock(return_value=_stream(body))
+        assert downloader.download_logo("http://x/big.png", target, "BIG") is False
+        assert list(tmp_path.iterdir()) == []
+
+    def test_oversized_response_does_not_replace_an_existing_logo(
+            self, downloader, old_logo, monkeypatch):
+        path, before = old_logo
+        monkeypatch.setattr(logo_downloader_module, "MAX_LOGO_BYTES", 4096)
+        downloader.session.get = MagicMock(
+            return_value=_stream(b"\x89PNG" + b"\x00" * 8192))
+        assert downloader.download_logo("http://x/big.png", path, "PHI") is False
+        assert path.read_bytes() == before
+        assert _leftovers(path.parent, keep=path.name) == []
+
+    def test_mid_download_failure_leaves_no_partial_file(self, downloader, tmp_path):
+        target = tmp_path / "CUT.png"
+        body = _png(Image.new("RGB", (200, 200), (5, 5, 5))) + b"\x00" * 4096
+        downloader.session.get = MagicMock(
+            return_value=_stream(body, chunk=256, die_after=512))
+        assert downloader.download_logo("http://x/cut.png", target, "CUT") is False
+        assert list(tmp_path.iterdir()) == []
+
+    def test_mid_download_failure_keeps_the_previous_logo(self, downloader, old_logo):
+        # The old code opened the final path for writing before the body
+        # arrived, so a dropped connection truncated the logo it was replacing.
+        path, before = old_logo
+        body = _png(Image.new("RGB", (200, 200), (5, 5, 5))) + b"\x00" * 4096
+        downloader.session.get = MagicMock(
+            return_value=_stream(body, chunk=256, die_after=512))
+        assert downloader.download_logo("http://x/cut.png", path, "PHI") is False
+        assert path.read_bytes() == before
+        assert _leftovers(path.parent, keep=path.name) == []
+
+    def test_non_image_content_type_is_rejected(self, downloader, old_logo):
+        # Rejected on the label alone, before the body is trusted: these bytes
+        # would decode, so only the content-type check stops them.
+        path, before = old_logo
+        body = _png(Image.new("RGB", (8, 8), (250, 0, 0)))
+        downloader.session.get = MagicMock(
+            return_value=_stream(body, content_type="text/html"))
+        assert downloader.download_logo("http://x/404", path, "PHI") is False
+        assert path.read_bytes() == before
+        assert _leftovers(path.parent, keep=path.name) == []
+
+    def test_bytes_that_do_not_decode_are_rejected(self, downloader, old_logo):
+        # A server that labels an error page image/png must not get it cached.
+        path, before = old_logo
+        downloader.session.get = MagicMock(
+            return_value=_stream(b"<html>oops</html>", content_type="image/png"))
+        assert downloader.download_logo("http://x/lie.png", path, "PHI") is False
+        assert path.read_bytes() == before
+        assert _leftovers(path.parent, keep=path.name) == []
+
+    def test_http_error_keeps_the_previous_logo(self, downloader, old_logo):
+        path, before = old_logo
+        response = _stream(b"")
+        response.raise_for_status.side_effect = requests.exceptions.HTTPError("503")
+        downloader.session.get = MagicMock(return_value=response)
+        assert downloader.download_logo("http://x/phi.png", path, "PHI") is False
+        assert path.read_bytes() == before
+        assert _leftovers(path.parent, keep=path.name) == []
+
+    def test_unwritable_directory_returns_false(self, downloader, tmp_path):
+        downloader.session.get = MagicMock()
+        with patch("src.logo_downloader.tempfile.mkstemp",
+                   side_effect=PermissionError("read-only")):
+            assert downloader.download_logo(
+                "http://x/phi.png", tmp_path / "PHI.png", "PHI") is False
+        downloader.session.get.assert_not_called()
+
+
+class TestDownloadLogoTransparency:
+    """Plugins paste logos with the image as its own mask; alpha must survive."""
+
+    def _download(self, downloader, tmp_path, body, content_type="image/png"):
+        target = tmp_path / "LOGO.png"
+        downloader.session.get = MagicMock(return_value=_stream(body, content_type))
+        assert downloader.download_logo("http://x/logo", target, "LOGO") is True
+        with Image.open(target) as img:
+            img.load()
+            return img.copy(), img.format
+
+    def test_rgba_alpha_is_kept_exactly(self, downloader, tmp_path):
+        src = Image.new("RGBA", (16, 16), (0, 0, 0, 0))
+        for x in range(16):
+            src.putpixel((x, 3), (200, 100, 50, x * 16))
+        out, _ = self._download(downloader, tmp_path, _png(src))
+        assert out.mode == "RGBA"
+        assert list(out.getdata()) == list(src.getdata())
+
+    def test_palette_transparency_becomes_alpha(self, downloader, tmp_path):
+        src = Image.new("P", (8, 8), 0)
+        src.putpalette([0, 0, 0, 255, 0, 0] + [0] * (254 * 3))
+        src.putpixel((4, 4), 1)
+        buf = io.BytesIO()
+        src.save(buf, "PNG", transparency=0)
+        out, _ = self._download(downloader, tmp_path, buf.getvalue())
+        assert out.mode == "RGBA"
+        assert out.getpixel((0, 0))[3] == 0
+        assert out.getpixel((4, 4)) == (255, 0, 0, 255)
+
+    def test_greyscale_transparency_becomes_alpha(self, downloader, tmp_path):
+        src = Image.new("L", (8, 8), 0)
+        src.putpixel((2, 2), 255)
+        buf = io.BytesIO()
+        src.save(buf, "PNG", transparency=0)
+        out, _ = self._download(downloader, tmp_path, buf.getvalue())
+        assert out.getpixel((0, 0))[3] == 0
+        assert out.getpixel((2, 2)) == (255, 255, 255, 255)
+
+    def test_jpeg_is_stored_as_opaque_rgba_png(self, downloader, tmp_path):
+        buf = io.BytesIO()
+        Image.new("RGB", (8, 8), (10, 200, 30)).save(buf, "JPEG", quality=95)
+        out, fmt = self._download(downloader, tmp_path, buf.getvalue(), "image/jpeg")
+        assert fmt == "PNG" and out.mode == "RGBA"
+        assert out.getchannel("A").getextrema() == (255, 255)
+
+
+class TestSharedDownloader:
+    def test_download_missing_logo_reuses_one_session(self, tmp_path, fresh_thread_state):
+        sessions = []
+        real_session = requests.Session
+
+        def counting_session(*args, **kwargs):
+            s = real_session(*args, **kwargs)
+            sessions.append(s)
+            return s
+
+        with patch("src.logo_downloader.requests.Session", side_effect=counting_session):
+            with patch.object(LogoDownloader, "download_logo", return_value=True) as dl:
+                for abbr in ("AAA", "BBB", "CCC"):
+                    assert download_missing_logo(
+                        "nfl", "1", abbr, tmp_path / f"{abbr}.png",
+                        logo_url=f"http://x/{abbr}.png",
+                        create_placeholder=False) is True
+        assert dl.call_count == 3
+        assert len(sessions) == 1
+
+    def test_each_thread_gets_its_own_downloader(self, fresh_thread_state):
+        here = logo_downloader_module.shared_downloader()
+        assert logo_downloader_module.shared_downloader() is here
+        seen = []
+        t = threading.Thread(target=lambda: seen.append(
+            logo_downloader_module.shared_downloader()))
+        t.start()
+        t.join()
+        assert seen and seen[0] is not here
+        assert seen[0].session is not here.session
+
+
+class TestPlaceholderWrite:
+    def test_no_write_probe_file_is_created(self, tmp_path):
+        created = []
+        real_touch = Path.touch
+
+        def spy_touch(self, *args, **kwargs):
+            created.append(self.name)
+            return real_touch(self, *args, **kwargs)
+
+        with patch.object(Path, "touch", spy_touch):
+            assert LogoDownloader().create_placeholder_logo("COLL", str(tmp_path)) is True
+        assert "test_write.tmp" not in created
+        assert sorted(p.name for p in tmp_path.iterdir()) == ["COLL.png"]
+
+    def test_unwritable_directory_returns_false(self, tmp_path):
+        with patch.object(LogoDownloader, "ensure_logo_directory", return_value=True), \
+             patch("src.logo_downloader.tempfile.mkstemp",
+                   side_effect=PermissionError("read-only")):
+            assert LogoDownloader().create_placeholder_logo("COLL", str(tmp_path)) is False
+        assert list(tmp_path.iterdir()) == []
+
+    def test_failed_save_keeps_the_previous_file(self, tmp_path):
+        path = tmp_path / "COLL.png"
+        Image.new("RGBA", (30, 30), (1, 2, 3, 255)).save(path)
+        before = path.read_bytes()
+        with patch("src.logo_downloader.os.replace", side_effect=OSError("disk full")):
+            assert LogoDownloader().create_placeholder_logo("COLL", str(tmp_path)) is False
+        assert path.read_bytes() == before
+        assert sorted(p.name for p in tmp_path.iterdir()) == ["COLL.png"]

test/test_logo_helper.py

@@ -33,7 +33,7 @@ def _no_real_chmod(monkeypatch):
     # Keep the permission helpers out of the way: their own env detection
     # is not what these tests are about.
     monkeypatch.setattr("src.common.logo_helper.ensure_directory_permissions", MagicMock())
-    monkeypatch.setattr("src.common.logo_helper.ensure_file_permissions", MagicMock())
+    monkeypatch.setattr("src.logo_downloader.ensure_file_permissions", MagicMock())
 
 
 @pytest.fixture
@@ -48,7 +48,8 @@ def write_logo(path: Path, size=(20, 20), color=(255, 0, 0), fmt="PNG") -> Path:
     return path
 
 
-def fake_response(content: bytes, chunk_size: int = 64 * 1024):
+def fake_response(content: bytes, chunk_size: int = 64 * 1024,
+                  content_type: str = "image/png"):
     """Stand-in for a streamed requests.Response.
 
     _download_logo opens `with session.get(..., stream=True)` and reads
@@ -61,6 +62,7 @@ def fake_response(content: bytes, chunk_size: int = 64 * 1024):
     response.__enter__.return_value = response
     response.__exit__.return_value = False
     response.raise_for_status = MagicMock()
+    response.headers = {"content-type": content_type}
 
     def _iter_content(*_args, **_kwargs):
         for i in range(0, len(content), chunk_size):
@@ -80,6 +82,7 @@ def endless_response(chunk: bytes = b"\x00" * 65536):
     response.__enter__.return_value = response
     response.__exit__.return_value = False
     response.raise_for_status = MagicMock()
+    response.headers = {"content-type": "image/png"}
 
     def _iter_content(*_args, **_kwargs):
         while True:
@@ -208,7 +211,7 @@ class TestLoadLogoWithDownload:
         # stream=True is load-bearing: it is what lets the size cap apply
         # before the body is buffered.
         helper.session.get.assert_called_once_with(
-            "http://x/logo.png", timeout=30, stream=True)
+            "http://x/logo.png", headers=None, timeout=30, stream=True)
 
     def test_download_failure_falls_back_to_placeholder(self, helper, tmp_path):
         helper.session.get = MagicMock(
@@ -241,7 +244,7 @@ class TestDownloadLogo:
         path.parent.mkdir()
         helper.session.get = MagicMock(return_value=fake_response(png_bytes()))
         with patch("src.common.logo_helper.ensure_directory_permissions") as dirs, \
-             patch("src.common.logo_helper.ensure_file_permissions") as files:
+             patch("src.logo_downloader.ensure_file_permissions") as files:
             helper._download_logo("http://x/logo.png", path)
         assert path.exists()
         dirs.assert_called_once()
@@ -284,6 +287,7 @@ class TestDownloadLogo:
         response.__enter__.return_value = response
         response.__exit__.return_value = False
         response.raise_for_status = MagicMock()
+        response.headers = {"content-type": "image/png"}
         response.iter_content = _dies_midway
         helper.session.get = MagicMock(return_value=response)
 
@@ -305,7 +309,7 @@ class TestDownloadLogo:
             seen.append(name)
             return fd, name
 
-        with patch("src.common.logo_helper.tempfile.mkstemp", side_effect=record):
+        with patch("src.logo_downloader.tempfile.mkstemp", side_effect=record):
             helper.session.get = MagicMock(return_value=fake_response(png_bytes()))
             helper._download_logo("http://x/logo.png", path)
             helper.session.get = MagicMock(return_value=fake_response(png_bytes()))
@@ -351,7 +355,7 @@ class TestDownloadLogo:
             def load(self):
                 raise Image.DecompressionBombError("too many pixels")
 
-        monkeypatch.setattr("src.common.logo_helper.Image.open", lambda *a, **kw: Bomb())
+        monkeypatch.setattr("src.logo_downloader.Image.open", lambda *a, **kw: Bomb())
         with pytest.raises(Image.DecompressionBombError):
             helper._download_logo("http://x/bomb.png", path)
         assert not path.exists()
@@ -420,7 +424,8 @@ class TestPlaceholderLogo:
 
 class TestSessionConfiguration:
     def test_user_agent_and_accept_headers(self, helper):
-        assert helper.session.headers["User-Agent"] == "LEDMatrix-Common/1.0"
+        from src.common.api_helper import USER_AGENT
+        assert helper.session.headers["User-Agent"] == USER_AGENT
         assert helper.session.headers["Accept"] == "image/*"