Add multi-user support via token-based routing and users.json config

Each user gets a unique secret token embedded in their webhook URL
(/webhook/:token). Credentials are loaded from users.json at startup
instead of environment variables, making it easy to add or remove users
without redeploying.

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

README.md

@@ -1,27 +1,65 @@
 # AudioPen Nextcloud Webhook
 
-A small Node.js webhook service that receives notes from AudioPen and uploads them to a folder in Nextcloud using WebDAV.
+A small Node.js webhook service that receives notes from AudioPen and uploads them to a folder in Nextcloud using WebDAV. Supports multiple users, each with their own Nextcloud credentials and a unique webhook token.
 
 When AudioPen sends a webhook request, the service:
 
-1. Receives the note content
-2. Creates a timestamped Markdown file
-3. Uploads the file to the configured Nextcloud folder
+1. Validates the token in the URL
+2. Receives the note content
+3. Creates a timestamped Markdown file
+4. Uploads the file to the configured Nextcloud folder
 
 Example filename:
 
 ```text
-note-2026-05-19T22-15-10.123Z.md
+2026-05-19T22-15-10.123Z-my-note-title.md
 ```
 
-## Example `.env`
+## Setup
 
-Create a file named `.env` in the project root directory:
+### 1. Configure users
+
+Copy `users.json.example` to `users.json` and fill in credentials for each user:
+
+```json
+{
+  "abc123secrettoken": {
+    "nextcloudUrl": "https://nextcloud.example.com",
+    "username": "alice",
+    "password": "alice-app-password",
+    "folder": "AudioPen"
+  }
+}
+```
+
+Each key is a secret token that identifies a user. Generate one with:
+
+```bash
+node -e "console.log(crypto.randomUUID())"
+```
+
+### 2. Configure the server
+
+Optionally create a `.env` file to set the port or a custom path to `users.json`:
 
 ```env
-NEXTCLOUD_URL=https://nextcloud.example.com
-NEXTCLOUD_USERNAME=myuser
-NEXTCLOUD_PASSWORD=my-app-password
-NEXTCLOUD_FOLDER=AudioPen
 PORT=3000
-```
+USERS_FILE=users.json
+```
+
+### 3. Run
+
+```bash
+npm install
+node server.js
+```
+
+### 4. Configure AudioPen
+
+In AudioPen's webhook settings, set the URL to:
+
+```
+https://your-server/webhook/<token>
+```
+
+Each user gets their own URL containing their unique token.