Remote Authentication

Biblioteca supports remote authentication via HTTP headers, allowing you to integrate with authentication proxies like Authentik, Keycloak, or Pocket-ID. This feature enables single sign-on (SSO) capabilities where authentication is handled by an external service.

How It Works

When remote authentication is enabled, Biblioteca reads the authenticated username from a configured HTTP header. The authentication proxy (Authentik, Keycloak, etc.) handles the login process and sets this header with the authenticated user’s identifier. Biblioteca then automatically logs in the user if they exist in the database.

Configuration

To enable remote authentication, set the REMOTE_USER_LOGIN_HEADER_NAME environment variable in your .env.local file:

REMOTE_USER_LOGIN_HEADER_NAME=HTTP_X_TOKEN_SUBJECT

The header name should be in the format HTTP_<HEADER_NAME> where <HEADER_NAME> is the actual HTTP header name in uppercase with hyphens replaced by underscores. For example:

• Header X-Token-Subject becomes HTTP_X_TOKEN_SUBJECT
• Header X-Remote-User becomes HTTP_X_REMOTE_USER
• Header X-Auth-Username becomes HTTP_X_AUTH_USERNAME

Setting Up Authentication Proxies

Authentik

Authentik is an open-source identity provider that can act as a reverse proxy for authentication.

1. Configure Outpost

In Authentik, you’ll need to set up an Outpost (Proxy Provider) that will handle authentication and forward requests to Biblioteca.

1. Go to Applications → Outposts in Authentik
2. Create a new Outpost or edit an existing one
3. Configure the Forward auth settings:
   • Set the External Host to your Biblioteca URL
   • Enable Forward auth (single application)

2. Configure Header Mapping

In your Outpost configuration, set up header mapping to pass the authenticated user:

1. In the Outpost settings, go to Header Mapping
2. Add a header mapping:
   • Header Name: X-Remote-User (or your preferred header name)
   • Expression: user.username or user.email (depending on what identifier you use in Biblioteca)

Alternatively, you can use Authentik’s default headers:

• X-Remote-User - contains the username
• X-Remote-Groups - contains user groups (if needed)

3. Configure Biblioteca

In your .env.local file:

REMOTE_USER_LOGIN_HEADER_NAME=HTTP_X_REMOTE_USER

4. Reverse Proxy Configuration

If you’re using Nginx as a reverse proxy in front of Authentik:

location / {
    proxy_pass http://authentik-outpost:9000;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    
    # Forward Authentik headers to Biblioteca
    proxy_set_header X-Remote-User $http_x_remote_user;
}

Keycloak

Keycloak is another popular open-source identity and access management solution.

1. Configure Keycloak Gatekeeper

Keycloak uses a Gatekeeper (or newer Keycloak Gatekeeper) to handle authentication as a reverse proxy.

2. Using Keycloak Gatekeeper

1. Deploy Keycloak Gatekeeper in front of Biblioteca
2. Configure it to authenticate users via Keycloak
3. Set up header forwarding to pass the authenticated username

Example configuration for Keycloak Gatekeeper:

listen: 0.0.0.0:3000
upstream-url: http://biblioteca:80
enable-json-logging: true
enable-request-logging: true
preserve-host: true
forwarding-username: X-Remote-User

3. Configure Biblioteca

In your .env.local file:

REMOTE_USER_LOGIN_HEADER_NAME=HTTP_X_REMOTE_USER

4. Using Nginx with Keycloak

If using Nginx with Keycloak’s authentication module:

location / {
    auth_request /auth;
    auth_request_set $user $upstream_http_x_remote_user;
    proxy_set_header X-Remote-User $user;
    proxy_pass http://biblioteca:80;
}

location = /auth {
    internal;
    proxy_pass https://keycloak.example.com/auth/realms/your-realm/protocol/openid-connect/userinfo;
    proxy_pass_request_body off;
    proxy_set_header Content-Length "";
    proxy_set_header X-Original-URI $request_uri;
}

Pocket-ID

Pocket-ID is a lightweight authentication proxy solution.

1. Configure Pocket-ID

1. Set up Pocket-ID as a reverse proxy in front of Biblioteca
2. Configure Pocket-ID to authenticate users
3. Set the header that Pocket-ID will use to pass the authenticated username

2. Header Configuration

Pocket-ID typically uses the X-Remote-User header by default, but this can be configured in your Pocket-ID settings.

3. Configure Biblioteca

In your .env.local file:

REMOTE_USER_LOGIN_HEADER_NAME=HTTP_X_REMOTE_USER

4. Example Nginx Configuration

If using Nginx with Pocket-ID:

location / {
    proxy_pass http://pocket-id:8080;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    
    # Forward Pocket-ID authentication header
    proxy_set_header X-Remote-User $http_x_remote_user;
}

General Reverse Proxy Setup

If you’re using a different authentication proxy or setting up a custom solution, here’s a general guide:

1. Authentication Flow

The typical flow is:

1. User accesses Biblioteca
2. Reverse proxy intercepts the request
3. If not authenticated, proxy redirects to authentication service
4. After authentication, proxy forwards request to Biblioteca with authentication header
5. Biblioteca reads the header and logs in the user

2. Required Headers

Your authentication proxy must set an HTTP header containing the authenticated username. Common header names include:

• X-Remote-User
• X-Auth-Username
• X-Token-Subject
• Remote-User

3. Nginx Example

Here’s a general Nginx configuration that can work with various authentication proxies:

server {
    listen 80;
    server_name biblioteca.example.com;

    location / {
        # Forward to authentication proxy
        proxy_pass http://auth-proxy:8080;
        
        # Preserve original headers
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        
        # Forward authentication header to Biblioteca
        proxy_set_header X-Remote-User $http_x_remote_user;
        
        # If your proxy uses a different header, adjust accordingly
        # proxy_set_header X-Remote-User $http_x_auth_username;
    }
}

Troubleshooting

User Not Logging In

1. Check Header Name: Verify that the header name in REMOTE_USER_LOGIN_HEADER_NAME matches what your proxy is sending. Remember the HTTP_ prefix and underscore format.

2. Check User Exists: Ensure the user exists in Biblioteca’s database with a username that matches the value in the authentication header.

3. Check Proxy Headers: Use browser developer tools or proxy logs to verify that the authentication header is being sent correctly.

4. Check Trusted Proxies: Verify that your proxy’s IP address is in the TRUSTED_PROXIES list.

Testing Configuration

You can test the header configuration by manually setting the header in a request:

curl -H "X-Remote-User: testuser" http://biblioteca.example.com/

Replace X-Remote-User with your configured header name (without the HTTP_ prefix).

Disabling Remote Authentication

To disable remote authentication, simply remove or comment out the REMOTE_USER_LOGIN_HEADER_NAME environment variable, or set it to an empty string:

REMOTE_USER_LOGIN_HEADER_NAME=

When disabled, Biblioteca will fall back to its standard form-based authentication.