Finger

Webfinger server written in Go.

Features

• 🍰 Easy YAML configuration
• 🪶 Single 8MB binary / 0% idle CPU / 4MB idle RAM
• ⚡️ Sub millisecond responses at 10,000 request per second
• 🐳 10MB Docker image

Install

Via go install:

go install git.maronato.dev/maronato/finger@latest

Via Docker:

docker run --name finger /
    -p 8080:8080 /
    git.maronato.dev/maronato/finger

Usage

If you installed it using go install, run

finger serve

To start the server on port 8080. Your resources will be queryable via locahost:8080/.well-known/webfinger?resource=<your-resource>

If you're using Docker, the use the same command in the install section.

By default, no resources will be exposed. You can create resources via a fingers.yml file. It should contain a collection of resources as keys and their attributes as their objects.

Some default URN aliases are provided via the built-in mapping (urns.yml). You can replace that with your own or use URNs directly in the fingers.yml file.

Here's an example:

# fingers.yml

# Resources go in the root of the file. Email address will have the acct: 
# prefix added automatically.
alice@example.com:
  # "avatar" is an alias of "http://webfinger.net/rel/avatar"
  # (see urns.yml for more)
  avatar: "https://example.com/alice-pic"

  # If the value is a URI, it'll be exposed as a webfinger link
  openid: "https://sso.example.com/"

  # If the value of the attribute is not a URI, it will be exposed as a
  # webfinger property
  name: "Alice Doe"

  # You can also specify URN's directly instead of the aliases
  http://webfinger.net/rel/profile-page: "https://example.com/user/alice"

bob@example.com:
  name: Bob Foo
  openid: "https://sso.example.com/"

# Resources can also be URIs
https://example.com/user/charlie:
  name: Charlie Baz
  profile: https://example.com/user/charlie

Example queries

Query Alice

GET http://localhost:8080/.well-known/webfinger?resource=acct:alice@example.com

{
  "subject": "acct:alice@example.com",
  "links": [
    {
      "rel": "avatar",
      "href": "https://example.com/alice-pic"
    },
    {
      "rel": "openid",
      "href": "https://sso.example.com/"
    },
    {
      "rel": "name",
      "href": "Alice Doe"
    },
    {
      "rel": "http://webfinger.net/rel/profile-page",
      "href": "https://example.com/user/alice"
    }
  ]
}

Query Bob

GET http://localhost:8080/.well-known/webfinger?resource=acct:bob@example.com

{
  "subject": "acct:bob@example.com",
  "links": [
    {
      "rel": "name",
      "href": "Bob Foo"
    },
    {
      "rel": "openid",
      "href": "https://sso.example.com/"
    }
  ]
}

Query Charlie

GET http://localhost:8080/.well-known/webfinger?resource=https://example.com/user/charlie

{
  "subject": "https://example.com/user/charlie",
  "links": [
    {
      "rel": "name",
      "href": "Charlie Baz"
    },
    {
      "rel": "profile",
      "href": "https://example.com/user/charlie"
    }
  ]
}

Configs

Here are the config options available. You can change them via command line flags or environment variables:

CLI flag	Env variable	Default	Description
fdsfds	gsfgfs	fgfsdgf	gdfsgdf