From 8854e570b01a07f79f75f169de3daa1336046215 Mon Sep 17 00:00:00 2001
From: panaaj <38519157+panaaj@users.noreply.github.com>
Date: Thu, 18 Apr 2024 17:54:13 +0930
Subject: [PATCH] Add Feature discovery to docs.

---
 docs/src/develop/plugins/server_plugin_api.md | 59 ++++++++++++++++++-
 docs/src/develop/webapps.md                   | 49 +++++++++++++++
 2 files changed, 106 insertions(+), 2 deletions(-)

diff --git a/docs/src/develop/plugins/server_plugin_api.md b/docs/src/develop/plugins/server_plugin_api.md
index 7dc8f7ab9..721768966 100644
--- a/docs/src/develop/plugins/server_plugin_api.md
+++ b/docs/src/develop/plugins/server_plugin_api.md
@@ -2,12 +2,67 @@
 
 # Server API for plugins
 
-SignalK server provides an interface to allow plugins to access / update the full data model, operations and send / receive deltas (updates).
+SignalK server provides an interface to allow plugins to:
+- Discover Features.
+- Access / update the full data model
+- send / receive deltas (updates)
+- Interact with APIs
+- Expose HTTP endpoints
 
-These functions are available via the `app` passed to the plugin when it is invoked.
+
+These functions are available via the `app` object passed to the plugin when it is invoked.
 
 ---
 
+### Discover Features
+
+#### `app.getFeatures(enabedOnly)`
+
+Returns an object detailing the available APIs and Plugins.
+
+The `enabledOnly` parameter is optional and has the following values:
+- `undefined` (not provided): list all features
+- `true`: list only enabled features
+- `false`: list only disabled features
+
+_Example:_
+```javascript
+let baseStations = app.getFeatures();
+
+{
+  "apis": [
+    "resources","course"
+  ],
+  "plugins": [
+    {
+      "id": "anchoralarm",
+      "name": "Anchor Alarm",
+      "version": "1.13.0",
+      "enabled": true
+    },
+    {
+      "id": "autopilot",
+      "name": "Autopilot Control",
+      "version": "1.4.0",
+      "enabled": false
+    },
+    {
+      "id": "sk-to-nmea2000",
+      "name": "Signal K to NMEA 2000",
+      "version": "2.17.0",
+      "enabled": false
+    },
+    {
+      "id": "udp-nmea-sender",
+      "name": "UDP NMEA0183 Sender",
+      "version": "2.0.0",
+      "enabled": false
+    }
+  ]
+}
+```
+
+
 ### Accessing the Data Model
 
 #### `app.getPath(path)`
diff --git a/docs/src/develop/webapps.md b/docs/src/develop/webapps.md
index a07adaad8..f71d998ed 100644
--- a/docs/src/develop/webapps.md
+++ b/docs/src/develop/webapps.md
@@ -93,6 +93,55 @@ GET /signalk/v1/applicationData/user/my-application
 [ "1.0", "1.1"]
 ```
 
+## Discovering Server Features
+
+To assist in tailoring a WebApps UI, it can "discover" the features supported by the server by sending a request to `/signalk/v2/features`.
+
+The response wil contain an object detailing the available APIs and Plugins.
+
+You can use the `enabled` parameter to specify to only return enabled or disabled features.
+
+To list only enabled features:
+`/signalk/v2/features?enable=1`
+
+To list only disabled features:
+`/signalk/v2/features?enable=0`
+
+_Example response:_
+```JSON
+{
+  "apis": [
+    "resources","course"
+  ],
+  "plugins": [
+    {
+      "id": "anchoralarm",
+      "name": "Anchor Alarm",
+      "version": "1.13.0",
+      "enabled": true
+    },
+    {
+      "id": "autopilot",
+      "name": "Autopilot Control",
+      "version": "1.4.0",
+      "enabled": false
+    },
+    {
+      "id": "sk-to-nmea2000",
+      "name": "Signal K to NMEA 2000",
+      "version": "2.17.0",
+      "enabled": false
+    },
+    {
+      "id": "udp-nmea-sender",
+      "name": "UDP NMEA0183 Sender",
+      "version": "2.0.0",
+      "enabled": false
+    }
+  ]
+}
+```
+
 ## Embedded Components and Admin UI / Server interfaces
 
 Embedded components are implemented using [Webpack Federated Modules](https://webpack.js.org/concepts/module-federation/) and [React Code Splitting](https://reactjs.org/docs/code-splitting.html).