OCAP Web component

OCAP Web serves and plays back Arma 3 mission recordings. It supports both legacy JSON recordings and chunked Protobuf format for efficient streaming of large recordings.

Installation

Pre-built binaries

Download the latest release from GitHub Releases:

Platform	Archive
Windows x64	`ocap-webserver-windows-amd64.zip`
Linux x64	`ocap-webserver-linux-amd64.tar.gz`
Linux ARM64	`ocap-webserver-linux-arm64.tar.gz`

Each archive contains the binary and required assets (markers, ammo icons).

Build from source

Requires Go 1.26+ and Node.js 24+.

# Build the frontend
cd ui && npm ci && npm run build && cd ..

# Build the server (frontend is embedded into the binary)
go build -o ocap-webserver ./cmd/ocap-webserver

# Or build everything via Docker
docker build -t ocap-webserver .

For development setup and workflow details, see CONTRIBUTING.md.

Docker

Docker images are available for linux/amd64 and linux/arm64 architectures in two variants:

Variant	Tag	Description
Slim (default)	`latest`, `v1.2.3`	Web server only
Full	`full`, `v1.2.3-full`	Web server + integrated Map Manager (GDAL, tippecanoe, pmtiles)

The full variant includes all tools needed for the Map Manager — an admin page that processes Arma 3 map data (grad_meh exports) into PMTiles and MapLibre styles directly from the web UI. The server auto-detects the available tools at startup; no extra configuration is needed.

# Slim — just the web server
docker run --name ocap-web -d \
  -p 5000:5000/tcp \
  -e OCAP_SECRET="same-secret" \
  -e OCAP_CONVERSION_ENABLED="true" \
  -v ocap-records:/var/lib/ocap/data \
  -v ocap-maps:/var/lib/ocap/maps \
  -v ocap-database:/var/lib/ocap/db \
  ghcr.io/ocap2/web:latest

# Full — web server with integrated Map Manager
docker run --name ocap-web -d \
  -p 5000:5000/tcp \
  -e OCAP_SECRET="same-secret" \
  -e OCAP_CONVERSION_ENABLED="true" \
  -v ocap-records:/var/lib/ocap/data \
  -v ocap-maps:/var/lib/ocap/maps \
  -v ocap-database:/var/lib/ocap/db \
  ghcr.io/ocap2/web:full

Volumes

Path	Description
`/var/lib/ocap/data`	Recording storage (JSON and chunked formats)
`/var/lib/ocap/maps`	Map tiles (download here)
`/var/lib/ocap/db`	SQLite database

Pelican Panel

A Pelican Panel egg is provided for deploying OCAP2 Web as a managed server instance. Import egg-ocap2-web.json in the Pelican admin panel under Eggs → Import Egg.

The egg uses the project's Docker image (ghcr.io/ocap2/web) directly. Persistent data (database, recordings, maps) is stored under /home/container/ via Pelican's volume mount.

Configuration

The configuration file is called setting.json. All settings can also be set via environment variables with the OCAP_ prefix. Nested keys use underscores: admin.sessionTTL → OCAP_ADMIN_SESSIONTTL.

{
  "listen": "127.0.0.1:5000",
  "secret": "your-secret",
  "logger": true,
  "admin": {
    "sessionTTL": "24h",
    "allowedSteamIds": ["76561198012345678"],
    "steamApiKey": ""
  },
  "customize": {
    "enabled": true,
    "websiteURL": "https://example.com",
    "websiteLogo": "https://example.com/logo.png"
  },
  "conversion": {
    "enabled": true,
    "interval": "5m"
  },
  "streaming": {
    "enabled": true
  }
}

Server

Setting	Env Var	Description	Default
`listen`	`OCAP_LISTEN`	Server address	`127.0.0.1:5000`
`prefixURL`	`OCAP_PREFIXURL`	URL prefix for all routes	`""`
`secret`	`OCAP_SECRET`	Shared secret — authenticates record uploads and signs admin session JWTs	required
`logger`	`OCAP_LOGGER`	Enable request logging to STDOUT	`false`

Paths

Setting	Env Var	Description	Default
`db`	`OCAP_DB`	Path to SQLite database	`data.db`
`data`	`OCAP_DATA`	Path to recording storage	`data`
`maps`	`OCAP_MAPS`	Path to map tiles	`maps`
`markers`	`OCAP_MARKERS`	Path to marker icons	`assets/markers`
`ammo`	`OCAP_AMMO`	Path to ammo icons	`assets/ammo`
`fonts`	`OCAP_FONTS`	Path to fonts	`assets/fonts`
`static`	`OCAP_STATIC`	Serve frontend from this directory instead of the embedded build	embedded

Docker note: The Docker image overrides path defaults to /var/lib/ocap/... and /usr/local/ocap/.... See Volumes for the Docker-specific paths.

Admin Authentication

Admin access uses Steam OpenID — no passwords. Admins authenticate via their Steam account and are authorized against an allowlist of Steam64 IDs.

Setting	Env Var	Description	Default
`admin.sessionTTL`	`OCAP_ADMIN_SESSIONTTL`	How long admin sessions last	`24h`
`admin.allowedSteamIds`	`OCAP_ADMIN_ALLOWEDSTEAMIDS`	Steam64 IDs authorized for admin access (comma-separated in env var)	`[]`
`admin.steamApiKey`	`OCAP_ADMIN_STEAMAPIKEY`	Steam Web API key for fetching display names and avatars (get one here)	`""`

The Steam API key is optional. Without it, the admin badge shows the raw Steam64 ID. With it, the admin's Steam profile picture and display name are shown.

Customization

Setting	Env Var	Description	Default
`customize.enabled`	`OCAP_CUSTOMIZE_ENABLED`	Enable the customize endpoint	`false`
`customize.websiteURL`	`OCAP_CUSTOMIZE_WEBSITEURL`	Link on the logo to your website	`""`
`customize.websiteLogo`	`OCAP_CUSTOMIZE_WEBSITELOGO`	URL to your website logo	`""`
`customize.websiteLogoSize`	`OCAP_CUSTOMIZE_WEBSITELOGOSIZE`	Logo size	`32px`
`customize.disableKillCount`	`OCAP_CUSTOMIZE_DISABLEKILLCOUNT`	Hide kill counts in the UI	`false`
`customize.headerTitle`	`OCAP_CUSTOMIZE_HEADERTITLE`	Custom header title	`""`
`customize.headerSubtitle`	`OCAP_CUSTOMIZE_HEADERSUBTITLE`	Custom header subtitle	`""`
`customize.cssOverrides`	`OCAP_CUSTOMIZE_CSSOVERRIDES`	CSS variable overrides (JSON object, see below)	`{}`

CSS Overrides

Override any CSS custom property to theme the UI without rebuilding. In setting.json:

"cssOverrides": {
  "--accent-primary": "#fcb00d",
  "--bg-dark": "#1a2a1a",
  "--text-on-accent": "#1a2a1a"
}

Via environment variable (for Docker), pass a JSON string:

OCAP_CUSTOMIZE_CSSOVERRIDES='{"--accent-primary":"#fcb00d","--bg-dark":"#1a2a1a","--text-on-accent":"#1a2a1a"}'

Common variables:

Variable	Description	Default
`--accent-primary`	Primary accent color (buttons, links, highlights)	`#4A9EFF`
`--accent-primary-dark`	Darker variant for gradients	`#3585dd`
`--accent-danger`	Danger/error color	`#FF4A4A`
`--accent-success`	Success color	`#2DD4A0`
`--accent-warning`	Warning color	`#FFB84A`
`--text-on-accent`	Text color on accent-colored buttons	`#fff`
`--bg-dark`	Main background	`#0a0f14`
`--bg-surface`	Card/panel background	`#151e2b`
`--text-primary`	Primary text color	`#e5ebf1`
`--side-blufor`	BLUFOR faction color (map markers)	`#00a8ff`
`--side-opfor`	OPFOR faction color	`#ff0000`
`--side-ind`	Independent faction color	`#00cc00`
`--side-civ`	Civilian faction color	`#c900ff`

Conversion

Large recordings can be automatically converted to chunked binary format for better performance.

Setting	Env Var	Description	Default
`conversion.enabled`	`OCAP_CONVERSION_ENABLED`	Enable automatic background conversion	`false`
`conversion.interval`	`OCAP_CONVERSION_INTERVAL`	How often to check for pending conversions	`5m`
`conversion.batchSize`	`OCAP_CONVERSION_BATCHSIZE`	Max recordings to convert per interval	`1`
`conversion.chunkSize`	`OCAP_CONVERSION_CHUNKSIZE`	Frames per chunk (~5 min at 1 fps)	`300`
`conversion.retryFailed`	`OCAP_CONVERSION_RETRYFAILED`	Retry previously failed conversions	`false`

Streaming

Live mission data can be streamed to the server via WebSocket.

Setting	Env Var	Description	Default
`streaming.enabled`	`OCAP_STREAMING_ENABLED`	Enable the WebSocket streaming endpoint	`false`
`streaming.pingInterval`	`OCAP_STREAMING_PINGINTERVAL`	Interval between WebSocket keepalive pings	`30s`
`streaming.pingTimeout`	`OCAP_STREAMING_PINGTIMEOUT`	Timeout waiting for pong response	`10s`

Large Recording Support

Overview

Traditional JSON recordings load entirely into browser memory, which causes crashes with large missions (500MB+). The chunked streaming system solves this by:

Converting recordings to binary format (Protobuf)
Splitting into chunks (~5 minutes each)
Loading only needed chunks during playback
Caching chunks in browser storage (OPFS/IndexedDB)

Storage Formats

Format	Extension	Use Case	Streaming	Performance
JSON	`.gz`	Legacy, small recordings	No	Baseline
Protobuf	`.pb`	Default chunked format	Yes	Good

Workflow

┌─────────────────────────────────────────────────────────────────┐
│                         UPLOAD                                  │
│  Mission ends → JSON.gz uploaded → Stored in data/ directory    │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                       CONVERSION                                │
│  Background worker (or CLI) converts to chunked binary format   │
│                                                                 │
│  data/mission.gz  →  data/mission/                              │
│                         ├── manifest.pb (metadata + entities)   │
│                         └── chunks/                             │
│                               ├── 0000.pb (frames 0-299)        │
│                               ├── 0001.pb (frames 300-599)      │
│                               └── ...                           │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                        PLAYBACK                                 │
│  1. Load manifest (entities, events, metadata)                  │
│  2. Load chunks on-demand as playback progresses                │
│  3. Cache chunks in browser (OPFS) for future playback          │
│  4. Evict old chunks from memory (max 3 in RAM)                 │
└─────────────────────────────────────────────────────────────────┘

For detailed flowcharts of playback and conversion, see Streaming Architecture.

CLI Commands

Convert recordings manually using the CLI:

# Convert a single file
./ocap-webserver convert --input data/mission.json.gz

# Convert all pending recordings
./ocap-webserver convert --all

# Show conversion status of all recordings
./ocap-webserver convert --status

# Change storage format for an existing operation
./ocap-webserver convert --set-format protobuf --id 1

File Structure After Conversion

data/
├── mission_name.gz              # Original JSON (preserved)
└── mission_name/                # Chunked binary format
    ├── manifest.pb              # Metadata, entities, events
    └── chunks/
        ├── 0000.pb              # Frames 0-299
        ├── 0001.pb              # Frames 300-599
        └── ...

Name		Name	Last commit message	Last commit date
Latest commit History 355 Commits
.github		.github
assets		assets
cmd		cmd
docker		docker
docs		docs
internal		internal
pkg/schemas/protobuf/v1		pkg/schemas/protobuf/v1
ui		ui
.dockerignore		.dockerignore
.gitignore		.gitignore
CLAUDE.md		CLAUDE.md
CONTRIBUTING.md		CONTRIBUTING.md
Dockerfile		Dockerfile
LICENSE		LICENSE
README.md		README.md
egg-ocap2-web.json		egg-ocap2-web.json
go.mod		go.mod
go.sum		go.sum
setting.json.example		setting.json.example

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Repository files navigation

OCAP Web component

Installation

Pre-built binaries

Build from source

Docker

Volumes

Pelican Panel

Configuration

Server

Paths

Admin Authentication

Customization

CSS Overrides

Conversion

Streaming

Large Recording Support

Overview

Storage Formats

Workflow

CLI Commands

File Structure After Conversion

About

Uh oh!

Releases

Packages

Uh oh!

Uh oh!

Contributors 14

Uh oh!

Languages

License

OCAP2/web

Folders and files

Latest commit

History

Repository files navigation

OCAP Web component

Installation

Pre-built binaries

Build from source

Docker

Volumes

Pelican Panel

Configuration

Server

Paths

Admin Authentication

Customization

CSS Overrides

Conversion

Streaming

Large Recording Support

Overview

Storage Formats

Workflow

CLI Commands

File Structure After Conversion

About

Resources

License

Contributing

Uh oh!

Stars

Watchers

Forks

Releases

Packages 0

Uh oh!

Uh oh!

Contributors 14

Uh oh!

Languages

Packages