Vervis/API.md

This document describes the Client-to-Server API of Vervis. If you're developing a frontend application, or a forge search engine, or anything else that wants to interact with Vervis instances, and wondering what language Vervis speaks, this is the document for you.

I suppose in the future it should sit on a Docusaurus website or something like that. For now it's here.

Public Browsing

The /browse page lists the public actors and resource hosted on the server. However there's currently no AP version of that page.

Server Information

NodeInfo isn't implemented yet.

Registration and Authorization

Creating an account on a Vervis instance allows to:

1. Create and manipulate resources (such as projects, repositories, teams)
2. View non-public information

Register the application

Register client

Send a POST request to the /oauth/apps endpoint:

curl -X POST \
    -F 'client_name=Anvil' \
    -F 'redirect_uris=urn:ietf:wg:oauth:2.0:oob' \
    -F 'scopes=read' \
    -F 'website=https://anvil.forgefed.org' \
    -F 'repository=https://codeberg.org/Anvil/Anvil' \
    https://vervis.example/oauth/apps

• redirect_uris currently supports specifying only one URI, and there are 2 options:
  • The special value urn:ietf:wg:oauth:2.0:oob, which means out-of-band: In this case, Vervis will respond with an HTML page containing a token that needs to be manually copied
  • An HTTPS URI: In this case, Vervis will redirect to the given URI
• The only supported scope is currently read, and despite the misleading name, it allows all API operations

The response, upon success, is a JSON object with 2 text fields:

• client_id
• client_secret

Keep these stored for future use.

Obtain an Application Access Token

Send a POST request to the /oauth/token endpoint:

curl -X POST \
    -F 'client_id=your_client_id_here' \
    -F 'client_secret=your_client_secret_here' \
    -F 'redirect_uri=urn:ietf:wg:oauth:2.0:oob' \
    -F 'grant_type=client_credentials' \
    https://vervis.example/oauth/token

• redirect_uri must be the one defined when registering the application

The response is a JSON object with:

• access_token: Text, keep for later use
• token_type: Text, always "Bearer"
• scope: Text, always "read"
• created_at: Integer, time as POSIX seconds

Verify the Application Access Token

You can verify the token works by sending a GET request to the /oauth/verify_credentials endpoint:

curl \
    -H 'Authorization: Bearer our_access_token_here' \
    https://vervis.example/oauth/verify_credentials

Register an Account

There's currently no API endpoint for creating a new account.

Log in as Existing User

Obtain authorization code

In a browser, send a GET request to the /oauth/authorize endpoint:

https://vervis.example/oauth/authorize
?client_id=CLIENT_ID
&scope=read
&redirect_uri=urn:ietf:wg:oauth:2.0:oob
&response_type=code

• If redirect_uri is the special one as in the example above, the response will be an HTML page containing the authorization code.
• Otherwise, Vervis will redirect to the redirect_uri, specifying the authorization code as a query parameter named "code":

redirect_uri?code=qDFUEaYrRK5c-HNmTCJbAzazwLRInJ7VHFat0wcMgCU

Obtain a User Access Token

Now that we have the code, send a POST request to the /oauth/token endpoint (which we previously used when registering the application):

curl -X POST \
    -F 'client_id=your_client_id_here' \
    -F 'client_secret=your_client_secret_here' \
    -F 'redirect_uri=urn:ietf:wg:oauth:2.0:oob' \
    -F 'grant_type=authorization_code' \
    -F 'code=user_authzcode_here' \
    -F 'scope=read' \
    https://vervis.example/oauth/token

The response is a JSON object with:

• access_token: Text, keep for later use
• token_type: Text, always "Bearer"
• scope: Text, always "read"
• created_at: Integer, time as POSIX seconds

Verify the User Access Token & Obtain Actor Object

You can verify the token works by sending a GET request to the /oauth/verify_credentials endpoint:

curl \
    -H 'Authorization: Bearer our_access_token_here' \
    https://vervis.example/oauth/verify_credentials

The response is a JSON object that has a url field, whose value is the HTTPS URI of the user's Person ActivityPub JSON object.

Perform Authorized Requests

You can now use the access token via the Authorization header, as in the curl example above.

• For GET requests, it allows to obtain non-public data
• For POST requests, it allows to publish ActivityPub activities via the user outbox

Getting ActivityPub objects

You can obtain an ActivityPub object by sending GET request to its id URI, with Content-Type being application/ld+json; profile="https://www.w3.org/ns/activitystreams. Unless you've been given such a URI, the starting points for discovering objects are:

• Public browsing page (which doesn't yet have an AP representation)
• The user Person object, whose URI can be obtained from /oauth/verify_credentials as described above

Publishing and Manipulating Objects

All object manipulation in Vervis is done using the ActivityPub C2S API, i.e. by POSTing Activity objects to the user's outbox. A list of supported activities will soon be added here and/or in the ForgeFed specification.