signalk-server

<!DOCTYPE html><html class="default" lang="en" data-base="../../../"><head><meta charset="utf-8"/><meta http-equiv="x-ua-compatible" content="IE=edge"/><title>Plugin Capabilities | Signal K</title><meta name="description" content="Documentation for Signal K"/><meta name="viewport" content="width=device-width, initial-scale=1"/><link rel="stylesheet" href="../../../assets/style.css?cache=1783009712609"/><link rel="stylesheet" href="../../../assets/highlight.css?cache=1783009712609"/><script defer src="../../../assets/main.js?cache=1783009712609"></script><script async src="../../../assets/icons.js?cache=1783009712609" id="tsd-icons-script"></script><script async src="../../../assets/search.js?cache=1783009712609" id="tsd-search-script"></script><script async src="../../../assets/navigation.js?cache=1783009712609" id="tsd-nav-script"></script><script async src="../../../assets/hierarchy.js?cache=1783009712609" id="tsd-hierarchy-script"></script><link rel="stylesheet" href="../../../assets/theme.css"/><script>if(window.self!==window.top){document.documentElement.classList.add('embedded')}</script></head><body><script>document.documentElement.dataset.theme = localStorage.getItem("tsd-theme") || "os";document.body.style.display="none";setTimeout(() => window.app?app.showPage():document.body.style.removeProperty("display"),500)</script><header class="tsd-page-toolbar"><div class="tsd-toolbar-contents container"><a href="../../../index.html" class="title"><img class="title-logo" src="../../../assets/logo.svg" alt="Signal K"/><svg class="title-home-icon" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-label="Documentation home"><path d="M3 9l9-7 9 7v11a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2z"></path><polyline points="9 22 9 12 15 12 15 22"></polyline></svg></a><button id="tsd-search-trigger" class="tsd-widget" aria-label="Search"><svg width="16" height="16" viewBox="0 0 16 16" fill="none" aria-hidden="true"><use href="../../../assets/icons.svg#icon-search"></use></svg>Search</button><dialog id="tsd-search" aria-label="Search"><input role="combobox" id="tsd-search-input" aria-controls="tsd-search-results" aria-autocomplete="list" aria-expanded="true" autocapitalize="off" autocomplete="off" placeholder="Search the docs" maxLength="100"/><ul role="listbox" id="tsd-search-results"></ul><div id="tsd-search-status" aria-live="polite" aria-atomic="true"><div>Preparing search index...</div></div></dialog><div id="tsd-toolbar-links"><a href="https://discord.gg/uuZrwz4dCS" target="_blank" rel="noopener" class="toolbar-icon visible@s" aria-label="Discord"><svg width="24" height="24" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 640 512"><path d="M524.5 69.8a1.5 1.5 0 0 0 -.8-.7A485.1 485.1 0 0 0 404.1 32a1.8 1.8 0 0 0 -1.9 .9 337.5 337.5 0 0 0 -14.9 30.6 447.8 447.8 0 0 0 -134.4 0 309.5 309.5 0 0 0 -15.1-30.6 1.9 1.9 0 0 0 -1.9-.9A483.7 483.7 0 0 0 116.1 69.1a1.7 1.7 0 0 0 -.8 .7C39.1 183.7 18.2 294.7 28.4 404.4a2 2 0 0 0 .8 1.4A487.7 487.7 0 0 0 176 479.9a1.9 1.9 0 0 0 2.1-.7A348.2 348.2 0 0 0 208.1 430.4a1.9 1.9 0 0 0 -1-2.6 321.2 321.2 0 0 1 -45.9-21.9 1.9 1.9 0 0 1 -.2-3.1c3.1-2.3 6.2-4.7 9.1-7.1a1.8 1.8 0 0 1 1.9-.3c96.2 43.9 200.4 43.9 295.5 0a1.8 1.8 0 0 1 1.9 .2c2.9 2.4 6 4.9 9.1 7.2a1.9 1.9 0 0 1 -.2 3.1 301.4 301.4 0 0 1 -45.9 21.8 1.9 1.9 0 0 0 -1 2.6 391.1 391.1 0 0 0 30 48.8 1.9 1.9 0 0 0 2.1 .7A486 486 0 0 0 610.7 405.7a1.9 1.9 0 0 0 .8-1.4C623.7 277.6 590.9 167.5 524.5 69.8zM222.5 337.6c-29 0-52.8-26.6-52.8-59.2S193.1 219.1 222.5 219.1c29.7 0 53.3 26.8 52.8 59.2C275.3 311 251.9 337.6 222.5 337.6zm195.4 0c-29 0-52.8-26.6-52.8-59.2S388.4 219.1 417.9 219.1c29.7 0 53.3 26.8 52.8 59.2C470.7 311 447.5 337.6 417.9 337.6z"></path></svg></a><a href="https://github.com/SignalK/signalk-server" target="_blank" rel="noopener" class="toolbar-icon visible@s" aria-label="Discord"><svg width="24" height="24" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><path d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3 .3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5 .3-6.2 2.3zm44.2-1.7c-2.9 .7-4.9 2.6-4.6 4.9 .3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3 .7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3 .3 2.9 2.3 3.9 1.6 1 3.6 .7 4.3-.7 .7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3 .7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3 .7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"></path></svg></a><a href="#" class="tsd-widget menu" id="tsd-toolbar-menu-trigger" data-toggle="menu" aria-label="Menu"><svg width="16" height="16" viewBox="0 0 16 16" fill="none" aria-hidden="true"><use href="../../../assets/icons.svg#icon-menu"></use></svg></a></div></div></header><div class="container container-main"><div class="col-content"><div class="tsd-page-title"><ul class="tsd-breadcrumb" aria-label="Breadcrumb"><li><a href="../../../Developing.html">Developing</a></li><li><a href="../../Plugins.html">Plugins</a></li><li><a href="../WASM_Plugins.html">WASM Plugins</a></li><li><a href="" aria-current="page">Plugin Capabilities</a></li></ul></div><div class="tsd-panel tsd-typography"><h1 id="plugin-capabilities" class="tsd-anchor-link">Plugin Capabilities<a href="#plugin-capabilities" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h1> <h2 id="capability-types" class="tsd-anchor-link">Capability Types<a href="#capability-types" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> Declare required capabilities in <code>package.json</code>: <table> <thead> <tr> <th>Capability</th> <th>Description</th> <th>Status</th> </tr> </thead> <tbody> <tr> <td><code>dataRead</code></td> <td>Read Signal K data model</td> <td>Supported</td> </tr> <tr> <td><code>dataWrite</code></td> <td>Emit delta messages</td> <td>Supported</td> </tr> <tr> <td><code>storage</code></td> <td>Write to VFS (<code>vfs-only</code>)</td> <td>Supported</td> </tr> <tr> <td><code>httpEndpoints</code></td> <td>Register custom HTTP endpoints</td> <td>Supported</td> </tr> <tr> <td><code>staticFiles</code></td> <td>Serve HTML/CSS/JS from <code>public/</code> folder</td> <td>Supported</td> </tr> <tr> <td><code>network</code></td> <td>HTTP requests (via as-fetch)</td> <td>Supported (AssemblyScript only)</td> </tr> <tr> <td><code>putHandlers</code></td> <td>Register PUT handlers for vessel control</td> <td>Supported</td> </tr> <tr> <td><code>rawSockets</code></td> <td>UDP socket access for radar, NMEA, etc.</td> <td>Supported</td> </tr> <tr> <td><code>serialPorts</code></td> <td>Serial port access</td> <td>Planned</td> </tr> </tbody> </table> <h2 id="network-api-assemblyscript" class="tsd-anchor-link">Network API (AssemblyScript)<a href="#network-api-assemblyscript" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> AssemblyScript plugins can make HTTP requests using the <code>as-fetch</code> library integrated into the SDK. Requirements: <ul> <li>Plugin must declare <code>"network": true</code> in manifest</li> <li>Server must be running Node.js 18+ (for native fetch support)</li> <li>Import network functions from SDK</li> <li>Must add <code>"transform": ["as-fetch/transform"]</code> to <code>asconfig.json</code> options</li> <li>Must set <code>"exportRuntime": true</code> in <code>asconfig.json</code> options</li> </ul> Example: HTTP GET Request <pre><code class="typescript">import { httpGet, hasNetworkCapability } from '@signalk/assemblyscript-plugin-sdk/assembly/network' import { debug, setError } from '@signalk/assemblyscript-plugin-sdk/assembly' class MyPlugin extends Plugin { start(config: string): i32 { // Always check capability first if (!hasNetworkCapability()) { setError('Network capability not granted') return 1 } // Make HTTP GET request const response = httpGet('https://api.example.com/data') if (response === null) { setError('HTTP request failed') return 1 } debug('Received: ' + response) return 0 } } </code><button type="button">Copy</button></pre> Available Network Functions: <pre><code class="typescript">// Check if network capability is granted hasNetworkCapability(): boolean // HTTP GET request - returns response body or null on error httpGet(url: string): string | null // HTTP POST request - returns status code or -1 on error httpPost(url: string, body: string): i32 // HTTP POST with response - returns response body or null httpPostWithResponse(url: string, body: string): string | null // HTTP PUT request - returns status code or -1 on error httpPut(url: string, body: string): i32 // HTTP DELETE request - returns status code or -1 on error httpDelete(url: string): i32 // Advanced HTTP request with full control httpRequest( url: string, method: string, body: string | null, contentType: string | null ): HttpResponse | null </code><button type="button">Copy</button></pre> Build Configuration (asconfig.json): For plugins using network capability: <pre><code class="json">{ "targets": { "release": { "outFile": "build/plugin.wasm", "optimize": true, "shrinkLevel": 2, "runtime": "stub" } }, "options": { "bindings": "esm", "exportRuntime": true, "transform": ["as-fetch/transform"] } } </code><button type="button">Copy</button></pre> Manifest Configuration: <pre><code class="json">{ "name": "my-plugin", "wasmCapabilities": { "network": true }, "dependencies": { "@signalk/assemblyscript-plugin-sdk": "^0.2.0", "as-fetch": "^2.1.4" } } </code><button type="button">Copy</button></pre> <h2 id="raw-sockets-api-udp" class="tsd-anchor-link">Raw Sockets API (UDP)<a href="#raw-sockets-api-udp" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> The <code>rawSockets</code> capability enables direct UDP socket access for plugins that need to communicate with devices like: <ul> <li>Marine radars (Navico, Raymarine, Furuno, Garmin)</li> <li>NMEA 0183 over UDP</li> <li>AIS receivers</li> <li>Other marine electronics using UDP multicast</li> </ul> Requirements: <ul> <li>Plugin must declare <code>"rawSockets": true</code> in manifest</li> <li>Sockets are non-blocking (poll-based receive)</li> <li>Automatic cleanup when plugin stops</li> </ul> Manifest Configuration: <pre><code class="json">{ "name": "my-radar-plugin", "wasmManifest": "plugin.wasm", "wasmCapabilities": { "rawSockets": true, "dataWrite": true } } </code><button type="button">Copy</button></pre> FFI Functions Available: <table> <thead> <tr> <th>Function</th> <th>Signature</th> <th>Description</th> </tr> </thead> <tbody> <tr> <td><code>sk_udp_create</code></td> <td><code>(type: i32) -> i32</code></td> <td>Create socket (0=udp4, 1=udp6). Returns socket_id or -1</td> </tr> <tr> <td><code>sk_udp_bind</code></td> <td><code>(socket_id, port) -> i32</code></td> <td>Bind to port (0=any). Returns 0 or -1</td> </tr> <tr> <td><code>sk_udp_join_multicast</code></td> <td><code>(socket_id, addr_ptr, addr_len, iface_ptr, iface_len) -> i32</code></td> <td>Join multicast group</td> </tr> <tr> <td><code>sk_udp_leave_multicast</code></td> <td><code>(socket_id, addr_ptr, addr_len, iface_ptr, iface_len) -> i32</code></td> <td>Leave multicast group</td> </tr> <tr> <td><code>sk_udp_set_multicast_ttl</code></td> <td><code>(socket_id, ttl) -> i32</code></td> <td>Set multicast TTL</td> </tr> <tr> <td><code>sk_udp_set_multicast_loopback</code></td> <td><code>(socket_id, enabled) -> i32</code></td> <td>Enable/disable loopback</td> </tr> <tr> <td><code>sk_udp_set_broadcast</code></td> <td><code>(socket_id, enabled) -> i32</code></td> <td>Enable/disable broadcast</td> </tr> <tr> <td><code>sk_udp_send</code></td> <td><code>(socket_id, addr_ptr, addr_len, port, data_ptr, data_len) -> i32</code></td> <td>Send datagram</td> </tr> <tr> <td><code>sk_udp_recv</code></td> <td><code>(socket_id, buf_ptr, buf_max_len, addr_out_ptr, port_out_ptr) -> i32</code></td> <td>Receive datagram (non-blocking)</td> </tr> <tr> <td><code>sk_udp_pending</code></td> <td><code>(socket_id) -> i32</code></td> <td>Get number of buffered datagrams</td> </tr> <tr> <td><code>sk_udp_close</code></td> <td><code>(socket_id) -> void</code></td> <td>Close socket</td> </tr> </tbody> </table> Rust Example: <pre><code class="rust">#[link(wasm_import_module = "env")] extern "C" { fn sk_udp_create(socket_type: i32) -> i32; fn sk_udp_bind(socket_id: i32, port: u16) -> i32; fn sk_udp_join_multicast( socket_id: i32, addr_ptr: *const u8, addr_len: usize, iface_ptr: *const u8, iface_len: usize ) -> i32; fn sk_udp_recv( socket_id: i32, buf_ptr: *mut u8, buf_max_len: usize, addr_out_ptr: *mut u8, port_out_ptr: *mut u16 ) -> i32; fn sk_udp_close(socket_id: i32); } // Example: Radar discovery fn start_radar_locator() -> i32 { // Create UDP socket let socket_id = unsafe { sk_udp_create(0) }; // udp4 if socket_id < 0 { return -1; } // Bind to radar discovery port if unsafe { sk_udp_bind(socket_id, 6878) } < 0 { return -1; } // Join radar multicast group let group = "239.254.2.0"; let iface = ""; if unsafe { sk_udp_join_multicast(socket_id, group.as_ptr(), group.len(), iface.as_ptr(), iface.len()) } < 0 { return -1; } socket_id } </code><button type="button">Copy</button></pre> Important Notes: <ul> <li>Receive is non-blocking - returns 0 if no data available</li> <li>Incoming datagrams are buffered (max 1000 per socket)</li> <li>Oldest datagrams are dropped if buffer is full</li> <li>All sockets are automatically closed when plugin stops</li> <li>Use <code>sk_udp_pending()</code> to check if data is available before calling <code>sk_udp_recv()</code></li> </ul> <h2 id="raw-sockets-api-tcp" class="tsd-anchor-link">Raw Sockets API (TCP)<a href="#raw-sockets-api-tcp" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> The <code>rawSockets</code> capability also enables TCP socket access for plugins that need persistent connections to devices: <ul> <li>Marine radars with TCP control (Furuno, Garmin)</li> <li>Devices requiring handshake/login protocols</li> <li>Any marine electronics using TCP</li> </ul> TCP sockets support both line-buffered mode (for text protocols with <code>\r\n</code> terminators) and raw mode (for binary protocols). FFI Functions Available: <table> <thead> <tr> <th>Function</th> <th>Signature</th> <th>Description</th> </tr> </thead> <tbody> <tr> <td><code>sk_tcp_create</code></td> <td><code>() -> i32</code></td> <td>Create TCP socket. Returns socket_id or -1</td> </tr> <tr> <td><code>sk_tcp_connect</code></td> <td><code>(socket_id, addr_ptr, addr_len, port) -> i32</code></td> <td>Initiate connection (non-blocking). Returns 0 or -1</td> </tr> <tr> <td><code>sk_tcp_connected</code></td> <td><code>(socket_id) -> i32</code></td> <td>Check connection status. Returns 1 if connected, 0 otherwise</td> </tr> <tr> <td><code>sk_tcp_set_line_buffering</code></td> <td><code>(socket_id, enabled) -> i32</code></td> <td>Set buffering mode (1=line, 0=raw). Default: line</td> </tr> <tr> <td><code>sk_tcp_send</code></td> <td><code>(socket_id, data_ptr, data_len) -> i32</code></td> <td>Send data. Returns bytes sent or -1</td> </tr> <tr> <td><code>sk_tcp_recv_line</code></td> <td><code>(socket_id, buf_ptr, buf_max_len) -> i32</code></td> <td>Receive complete line (line mode). Returns len or 0</td> </tr> <tr> <td><code>sk_tcp_recv_raw</code></td> <td><code>(socket_id, buf_ptr, buf_max_len) -> i32</code></td> <td>Receive raw data (raw mode). Returns len or 0</td> </tr> <tr> <td><code>sk_tcp_pending</code></td> <td><code>(socket_id) -> i32</code></td> <td>Get buffered item count</td> </tr> <tr> <td><code>sk_tcp_close</code></td> <td><code>(socket_id) -> void</code></td> <td>Close socket</td> </tr> </tbody> </table> Rust Example: <pre><code class="rust">#[link(wasm_import_module = "env")] extern "C" { fn sk_tcp_create() -> i32; fn sk_tcp_connect(socket_id: i32, addr_ptr: *const u8, addr_len: usize, port: u16) -> i32; fn sk_tcp_connected(socket_id: i32) -> i32; fn sk_tcp_set_line_buffering(socket_id: i32, enabled: i32) -> i32; fn sk_tcp_send(socket_id: i32, data_ptr: *const u8, data_len: usize) -> i32; fn sk_tcp_recv_line(socket_id: i32, buf_ptr: *mut u8, buf_max_len: usize) -> i32; fn sk_tcp_recv_raw(socket_id: i32, buf_ptr: *mut u8, buf_max_len: usize) -> i32; fn sk_tcp_pending(socket_id: i32) -> i32; fn sk_tcp_close(socket_id: i32); } // Example: Furuno radar control connection fn connect_furuno_radar(ip: &str, port: u16) -> i32 { // Create TCP socket let socket_id = unsafe { sk_tcp_create() }; if socket_id < 0 { return -1; } // Initiate connection (non-blocking) if unsafe { sk_tcp_connect(socket_id, ip.as_ptr(), ip.len(), port) } < 0 { return -1; } socket_id } fn poll_connection(socket_id: i32) { // Check if connected if unsafe { sk_tcp_connected(socket_id) } != 1 { return; // Still connecting } // Send command with \r\n terminator let cmd = "$S69,2,0,0,60,300,0\r\n"; unsafe { sk_tcp_send(socket_id, cmd.as_ptr(), cmd.len()) }; // Receive response line let mut buf = [0u8; 256]; let len = unsafe { sk_tcp_recv_line(socket_id, buf.as_mut_ptr(), buf.len()) }; if len > 0 { // Process response } } </code><button type="button">Copy</button></pre> Important Notes: <ul> <li>Connection is non-blocking - poll <code>sk_tcp_connected()</code> until connected</li> <li>Line-buffered mode (default) splits incoming data on <code>\r\n</code> or <code>\n</code></li> <li>Raw mode returns data as it arrives (for binary protocols)</li> <li>Use <code>sk_tcp_pending()</code> to check if data is available</li> <li>All sockets are automatically closed when plugin stops</li> </ul> <h2 id="put-handlers-api" class="tsd-anchor-link">PUT Handlers API<a href="#put-handlers-api" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> WASM plugins can register PUT handlers to respond to PUT requests from clients, enabling vessel control and configuration management. Requirements: <ul> <li>Plugin must declare <code>"putHandlers": true</code> in manifest</li> <li>Import PUT handler functions from FFI</li> <li>Register handlers during <code>plugin_start()</code></li> <li>Export handler functions with correct naming convention</li> </ul> Manifest Configuration: <pre><code class="json">{ "name": "my-plugin", "wasmManifest": "plugin.wasm", "wasmCapabilities": { "putHandlers": true } } </code><button type="button">Copy</button></pre> Handler Naming Convention: Format: <code>handle_put_{context}_{path}</code> <ul> <li>Replace all dots (<code>.</code>) with underscores (<code>_</code>)</li> <li>Convert to lowercase (recommended)</li> </ul> Examples: <table> <thead> <tr> <th>Context</th> <th>Path</th> <th>Handler Function Name</th> </tr> </thead> <tbody> <tr> <td><code>vessels.self</code></td> <td><code>navigation.anchor.position</code></td> <td><code>handle_put_vessels_self_navigation_anchor_position</code></td> </tr> <tr> <td><code>vessels.self</code></td> <td><code>steering.autopilot.target.headingTrue</code></td> <td><code>handle_put_vessels_self_steering_autopilot_target_headingTrue</code></td> </tr> </tbody> </table> Response Format: <pre><code class="json">{ "state": "COMPLETED", "statusCode": 200, "message": "Operation successful" } </code><button type="button">Copy</button></pre> <ul> <li><code>state</code> - Request state: <code>COMPLETED</code> or <code>PENDING</code></li> <li><code>statusCode</code> - HTTP status code (200, 400, 403, 500, 501)</li> <li><code>message</code> - Human-readable message (optional)</li> </ul> <h2 id="storage-api" class="tsd-anchor-link">Storage API<a href="#storage-api" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> Plugins have access to isolated virtual filesystem: <pre><code class="rust">use std::fs; fn save_state() { // Plugin sees "/" as its VFS root fs::write("/data/state.json", state_json).unwrap(); } fn load_state() -> String { fs::read_to_string("/data/state.json").unwrap_or_default() } </code><button type="button">Copy</button></pre> VFS Structure: <pre><code>/ (VFS root) ├── data/ # Persistent storage ├── config/ # Plugin-managed config └── tmp/ # Temporary files </code><button>Copy</button></pre> <h2 id="delta-emission" class="tsd-anchor-link">Delta Emission<a href="#delta-emission" aria-label="Permalink" class="tsd-anchor-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><use href="../../../assets/icons.svg#icon-anchor"></use></svg></a></h2> Emit delta messages to update Signal K data: <pre><code class="rust">fn emit_position_delta() { let delta = r#"{ "context": "vessels.self", "updates": [{ "source": { "label": "example-wasm", "type": "plugin" }, "timestamp": "2025-12-01T10:00:00.000Z", "values": [{ "path": "navigation.position", "value": { "latitude": 60.1, "longitude": 24.9 } }] }] }"#; handle_message(&delta); } </code><button type="button">Copy</button></pre> </div></div><div class="col-sidebar"><div class="page-menu"><details open class="tsd-accordion tsd-page-navigation"><summary class="tsd-accordion-summary"><svg width="20" height="20" viewBox="0 0 24 24" fill="none" aria-hidden="true"><use href="../../../assets/icons.svg#icon-chevronDown"></use></svg><h3>On This Page</h3></summary><div class="tsd-accordion-details"><a href="#capability-types">Capability Types</a><a href="#network-api-assemblyscript">Network API (AssemblyScript)</a><a href="#raw-sockets-api-udp">Raw Sockets API (UDP)</a><a href="#raw-sockets-api-tcp">Raw Sockets API (TCP)</a><a href="#put-handlers-api">PUT Handlers API</a><a href="#storage-api">S