From 8b6e2875a7a7f2c98f756089a291599dedea0cef Mon Sep 17 00:00:00 2001
From: Andrew Williams <andy@tensixtyone.com>
Date: Mon, 1 May 2023 07:27:44 +0100
Subject: [PATCH] Generate Mastodon links

---
 README.md | 22 +++++++++++++++++++++-
 app.py    | 50 +++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index d7e1afc..e2b928f 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 A simple, Flask-based webfinger handler.
 
-Simple Webfinger was created to provide an OIDC href from a basic YAML configuration file. Ideally to use with Tailscale and Authentik.
+Simple Webfinger was created to provide an OIDC href from a basic YAML configuration file. Ideally for use with Tailscale and Authentik.
 
 ## Configuration
 
@@ -13,4 +13,24 @@ The `example-config.yaml` has the basic layout of the YAML file, which has the f
 | `domain`    | `doofnet.uk`                | The domain to respond to, it'll return 404s for anything else |
 | `oidc_href` | `https://id.doofnet.uk/...` | The href to return for OIDC rels                              |
 
+### Accounts
 
+Accounts can be defined under the `accounts` key, and a key for each user, for example:
+
+```yaml
+accounts:
+  nikdoof:
+    mastodon: nikdoof@mastodon.incognitus.net
+    aliases: []
+    properties: []
+    links: []
+```
+
+The app will only reply to accounts listed in the configuration, otherwise, it'll return a 404.
+
+| Key          | Value Example                     | Description                                                     |
+| ------------ | --------------------------------- | --------------------------------------------------------------- |
+| `mastodon`   | `nikdoof@mastodon.incognitus.net` | A Mastodon account to generate the related links/properties for |
+| `aliases`    | `[]`                              | A list of aliases to include in the response for the account    |
+| `links`      | `[]`                              | A list of dicts to include in the response                      |
+| `properties` | `[]`                              | A list of dicts to include in the response                      |
diff --git a/app.py b/app.py
index 3d069ea..6438f6c 100644
--- a/app.py
+++ b/app.py
@@ -1,3 +1,5 @@
+from urllib.parse import urlparse
+
 from flask import Flask, request, abort
 import yaml
 
@@ -7,19 +9,57 @@ with open('config.yaml', 'rb') as fobj:
     data = yaml.load(fobj, yaml.SafeLoader)
 
 
+def get_account_links(user):
+    links = []
+    account_data = data['accounts'][user]
+
+    # Append custom links
+    if 'links' in account_data:
+        links.extend(account_data['links'])
+
+    if 'mastodon' in account_data:
+        account, domain = account_data['mastodon'].split('@')
+        links.extend([
+            {'rel': 'http://webfinger.net/rel/profile-page', 'type': 'text/html', 'href': 'https://{0}/@{1}'.format(domain, account)},
+            {'rel': 'self', 'type': 'application/activity+json', 'href': 'https://{0}/users/{1}'.format(domain, account)},
+            {'rel': 'http://ostatus.org/schema/1.0/subscribe', 'template': "https://{0}/authorize_interaction?uri={{uri}}".format(domain)}
+        ])
+
+    # Append the OIDC link
+    if 'oidc_href' in data:
+        links.append({
+            'rel': 'http://openid.net/specs/connect/1.0/issuer',
+            'href': data['oidc_href'],
+        })
+
+    return links
+
+
+def filter_links(links, rel):
+    new_links = []
+    for link in links:
+        if link['rel'] == rel:
+            new_links.append(link)
+    return new_links
+
+
 @app.route("/.well-known/webfinger")
 def webfinger():
     resource = request.args.get('resource')
+    account, domain = urlparse(resource).path.split('@')
 
-    if resource.split('@')[1] != data['domain']:
+    if domain != data['domain'] or account not in data['accounts']:
         abort(404)
 
+    links = get_account_links(account)
+
+    rel = request.args.get('rel')
+    if rel:
+        links = filter_links(links, rel)
+
     return {
         'subject': resource,
-        'links': [{
-            'rel': "http://openid.net/specs/connect/1.0/issuer",
-            'href': data['oidc_href'],
-        }]
+        'links': links
     }