Files
LEDMatrix/web_interface
ChuckandClaude Opus 5.5 8879886e50 fix(web): keep exception messages out of API responses (py/stack-trace-exposure)
CodeQL had ~40 open py/stack-trace-exposure alerts on main. Almost all
flowed through describe_exception(), which returned "TypeName: message"
(redacted, capped); the rest through _run_systemctl_command's str(err),
WiFiManager's `return False, str(e)`, unit_refresh's f-strings and two
str(e)/f"{err}" messages in api_v3/__init__.py.

describe_exception() now returns a reason code -- the type, plus the
errno symbol for an OSError ("OSError:EIO", "PermissionError:EACCES") --
and logs the redacted message itself. That keeps what #538 wanted (a
failing disk still says EIO in the response) without quoting paths,
URLs or library internals, and fixes every call site at once; the
test_no_api_v3_handler_discards_its_exception policy still holds.

Service results: _get_display_service_status returns active/returncode
only, and the on-demand start/stop `service` result keeps
returncode/active/started/status but drops systemctl stdout/stderr
(logged on failure). Nothing in web_interface/static, the templates or
the MQTT bridge reads those fields. The Starlark SIGKILL-restart error
no longer returns systemctl stderr as `details`.

WiFi, unit-refresh, config-save and plugin-removal failures now say
what failed with the reason code and point at the log. display.py is
untouched (draft #773 edits it).

Tests: test_api_v3_no_exception_text.py drives one route per affected
file with a marker in the exception message and asserts it never
reaches the body; all 13 fail on origin/main, and targeted mutations
(drop the service filter, put stderr back, str(e) in WiFiManager,
{e} in unit_refresh, {install_err} in system.py, message back in
describe_exception) each fail at least one. Tests that asserted the old
message-in-details contract now assert the reason code.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-05 16:41:07 -04:00
..

LED Matrix Web Interface V3

Modern, production web interface for controlling the LED Matrix display.

Overview

This directory contains the active V3 web interface with the following features:

  • Real-time display preview via Server-Sent Events (SSE)
  • Plugin management and configuration
  • System monitoring and logs
  • Modern, responsive UI
  • RESTful API

Directory Structure

web_interface/
├── app.py                    # Main Flask application
├── start.py                  # Startup script
├── requirements.txt          # Python dependencies
├── blueprints/               # Flask blueprints
│   ├── api_v3/              # API endpoints (package: config, display,
│   │                        #   plugins, system, backup, fonts, misc,
│   │                        #   wifi, starlark)
│   └── pages_v3.py          # Page routes
├── tailwind/                 # Tailwind config + input CSS (build inputs,
│                             #   not served; see "Styling" below)
├── templates/                # HTML templates
│   └── v3/
│       ├── base.html
│       └── partials/
└── static/                   # CSS/JS assets
    └── v3/
        ├── tailwind.css      # GENERATED utility classes (committed)
        ├── plugin-frame.css  # GENERATED styles for plugin web_ui/ iframes
        ├── app.css           # hand-written: tokens, components, dark theme
        ├── app.js
        ├── manifest.json     # PWA manifest
        ├── plugins_manager.js
        ├── icons/            # PWA / touch icons
        ├── js/               # Alpine, htmx, app shell, widgets, utils
        └── vendor/           # codemirror, fontawesome

Styling (Tailwind CSS)

Templates and JS use Tailwind utility classes. The CSS for them is generated on a dev machine or in CI and committed, so the Pi never builds anything and the UI needs no CDN (it has to work in AP mode, with no internet).

  • static/v3/tailwind.css holds the utilities. It is generated from the classes found in templates/v3/, static/v3/**/*.js and blueprints/, so it only contains what the UI uses.
  • static/v3/app.css is hand-written: theme tokens, base element styles, components (.btn, .card, .nav-tab, ...) and the dark theme ([data-theme="dark"] ... overrides). base.html loads it after tailwind.css, so its rules win over utilities of equal specificity. Don't add utility classes to it; use the class and rebuild.
  • static/v3/plugin-frame.css styles plugin web_ui/ fragments served by /v3/plugin-ui/<plugin>/web-ui/<file> in an iframe. Their markup lives in plugin repos, so it can't be scanned; its config safelists the common utility families instead.

After changing a template, a static JS file or anything in tailwind/, rebuild and commit the CSS with your change:

python3 scripts/build_css.py          # rewrites tailwind.css and plugin-frame.css
python3 scripts/build_css.py --check  # what CI runs: fails if they are stale

No Node or npm is needed. The script downloads Tailwind's standalone CLI (pinned version, SHA-256 checked) for your OS once and caches it outside the repo (LEDMATRIX_TAILWIND_CACHE overrides where). CI runs --check on every PR.

Where to change what:

  • A class built at runtime (`bg-${color}-100`) is invisible to the scanner: add it to safelist in tailwind/tailwind.config.js, or better, write the full class names in the code.
  • Colours, font sizes and shadows that differ from stock Tailwind (darker gray text, emerald/amber button fills, token-based shadows) are set in the theme of tailwind/tailwind.config.js.
  • Dark mode is the data-theme="dark" attribute on <html>; the dark: variant is configured to match it.

Running the Web Interface

Standalone (Development)

From the project root:

python3 web_interface/start.py

As a Service (Production)

The web interface can run as a systemd service that starts automatically based on the web_display_autostart configuration setting:

sudo systemctl start ledmatrix-web
sudo systemctl enable ledmatrix-web  # Start on boot

Accessing the Interface

Once running, access the web interface at:

Configuration

The web interface reads configuration from:

  • config/config.json - Main configuration
  • config/config_secrets.json - API keys and secrets

API Documentation

The V3 API is the api_v3 blueprint, registered at /api/v3/ in app.py. For the complete list and request/response formats, see docs/REST_API_REFERENCE.md. Quick reference for the most common endpoints:

Configuration

  • GET /api/v3/config/main - Get main configuration
  • POST /api/v3/config/main - Save main configuration
  • GET /api/v3/config/secrets - Get secrets configuration
  • POST /api/v3/config/raw/main - Save raw main config (Config Editor)
  • POST /api/v3/config/raw/secrets - Save raw secrets

Display & System Control

  • GET /api/v3/system/status - System status
  • POST /api/v3/system/action - Control display (action body: start_display, stop_display, restart_display_service, restart_web_service, git_pull, reboot_system, shutdown_system, enable_autostart, disable_autostart)
  • GET /api/v3/display/current - Current display frame
  • GET /api/v3/display/on-demand/status - On-demand status
  • POST /api/v3/display/on-demand/start - Trigger on-demand display
  • POST /api/v3/display/on-demand/stop - Clear on-demand

Plugins

  • GET /api/v3/plugins/installed - List installed plugins
  • GET /api/v3/plugins/config?plugin_id=<id> - Get plugin config
  • POST /api/v3/plugins/config - Update plugin configuration
  • GET /api/v3/plugins/schema?plugin_id=<id> - Get plugin schema
  • POST /api/v3/plugins/toggle - Enable/disable plugin
  • POST /api/v3/plugins/install - Install from registry
  • POST /api/v3/plugins/install-from-url - Install from GitHub URL
  • POST /api/v3/plugins/uninstall - Uninstall plugin
  • POST /api/v3/plugins/update - Update plugin

Plugin Store

  • GET /api/v3/plugins/store/list - List available registry plugins
  • GET /api/v3/plugins/store/github-status - GitHub authentication status
  • POST /api/v3/plugins/store/refresh - Refresh registry from GitHub

Real-time Streams (SSE)

SSE stream endpoints are defined directly on the Flask app in app.py (stream_stats, stream_display, stream_logs, followed by their CSRF exemption and rate-limit hookup), not on the api_v3 blueprint:

  • GET /api/v3/stream/stats - System statistics stream
  • GET /api/v3/stream/display - Display preview stream
  • GET /api/v3/stream/logs - Service logs stream

Development

When making changes to the web interface:

  1. Edit files in this directory
  2. Test changes by running python3 web_interface/start.py
  3. Restart the service if running: sudo systemctl restart ledmatrix-web

Notes

  • Templates and static files use the v3/ prefix to allow for future versions
  • The interface uses Flask blueprints for modular organization
  • SSE streams provide real-time updates without polling