POST /api/v3/display/on-demand/start delivered the request (control socket, else the file mailbox) before it checked the display service. With the service stopped the socket is absent, so the request went to the mailbox; the route then answered 400 "Display service is not running" when start_service was off, or 500 "Failed to start display service" when the start failed. The display reads that mailbox with max_age=3600 and never checks a request's timestamp, so the next time it was started it ran the refused request, pinned if asked. The service is now checked before anything is delivered, and nothing is posted when start_service is off and the service is down. When the start itself fails, the request is withdrawn from the mailbox, but only while the mailbox still holds this request_id (the compare-before-delete the display's _consume_on_demand_request uses), so a newer request posted in the meantime is left for the display. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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.cssholds the utilities. It is generated from the classes found intemplates/v3/,static/v3/**/*.jsandblueprints/, so it only contains what the UI uses.static/v3/app.cssis hand-written: theme tokens, base element styles, components (.btn,.card,.nav-tab, ...) and the dark theme ([data-theme="dark"] ...overrides).base.htmlloads it aftertailwind.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.cssstyles pluginweb_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 tosafelistintailwind/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
themeoftailwind/tailwind.config.js. - Dark mode is the
data-theme="dark"attribute on<html>; thedark: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:
- Local: http://localhost:5000
- Network: http://:5000
Configuration
The web interface reads configuration from:
config/config.json- Main configurationconfig/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 configurationPOST /api/v3/config/main- Save main configurationGET /api/v3/config/secrets- Get secrets configurationPOST /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 statusPOST /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 frameGET /api/v3/display/on-demand/status- On-demand statusPOST /api/v3/display/on-demand/start- Trigger on-demand displayPOST /api/v3/display/on-demand/stop- Clear on-demand
Plugins
GET /api/v3/plugins/installed- List installed pluginsGET /api/v3/plugins/config?plugin_id=<id>- Get plugin configPOST /api/v3/plugins/config- Update plugin configurationGET /api/v3/plugins/schema?plugin_id=<id>- Get plugin schemaPOST /api/v3/plugins/toggle- Enable/disable pluginPOST /api/v3/plugins/install- Install from registryPOST /api/v3/plugins/install-from-url- Install from GitHub URLPOST /api/v3/plugins/uninstall- Uninstall pluginPOST /api/v3/plugins/update- Update plugin
Plugin Store
GET /api/v3/plugins/store/list- List available registry pluginsGET /api/v3/plugins/store/github-status- GitHub authentication statusPOST /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 streamGET /api/v3/stream/display- Display preview streamGET /api/v3/stream/logs- Service logs stream
Development
When making changes to the web interface:
- Edit files in this directory
- Test changes by running
python3 web_interface/start.py - 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