Implement webfinger support

federation/hostmeta/generators.py

@@ -1,4 +1,5 @@
-from xrd import XRD, Link
+from base64 import b64encode
+from xrd import XRD, Link, Element
 
 
 def generate_host_meta(template=None, *args, **kwargs):
@@ -18,6 +19,23 @@ def generate_host_meta(template=None, *args, **kwargs):
     return hostmeta.render()
 
 
+def generate_legacy_webfinger(template=None, *args, **kwargs):
+    """Generate a legacy webfinger XRD document.
+
+    Args:
+        template (str, optional)    - Ready template to fill with args, for example "diaspora".
+        **kwargs                    - Template specific key-value pairs to fill in, see classes.
+
+    Returns:
+        str                         - XRD document
+    """
+    if template == "diaspora":
+        hostmeta = DiasporaWebFinger(*args, **kwargs)
+    else:
+        hostmeta = BaseLegacyWebFinger(*args, **kwargs)
+    return hostmeta.render()
+
+
 class BaseHostMeta(object):
     def __init__(self, *args, **kwargs):
         self.xrd = XRD()
@@ -40,3 +58,70 @@ class DiasporaHostMeta(BaseHostMeta):
             template='%s/webfinger?q={uri}' % kwargs["webfinger_host"]
         )
         self.xrd.links.append(link)
+
+
+class BaseLegacyWebFinger(BaseHostMeta):
+    """Legacy XRD WebFinger.
+
+    See: https://code.google.com/p/webfinger/wiki/WebFingerProtocol
+    """
+    def __init__(self, address, *args, **kwargs):
+        super(BaseLegacyWebFinger, self).__init__(*args, **kwargs)
+        subject = Element("Subject", "acct:%s" % address)
+        self.xrd.elements.append(subject)
+
+
+class DiasporaWebFinger(BaseLegacyWebFinger):
+    """Diaspora version of legacy WebFinger.
+
+    Requires keyword args:
+        handle (str)        - eg user@domain.tld
+        host (str)          - eg https://domain.tld
+        guid (str)          - guid of user
+        public_key (str)    - public key
+    """
+    def __init__(self, handle, host, guid, public_key, *args, **kwargs):
+        super(DiasporaWebFinger, self).__init__(handle, *args, **kwargs)
+        self.xrd.elements.append(Element("Alias", "%s/people/%s" % (
+            host, guid
+        )))
+        username = handle.split("@")[0]
+        self.xrd.links.append(Link(
+            rel="http://microformats.org/profile/hcard",
+            type_="text/html",
+            href="%s/hcard/users/%s" %(
+                host, username
+            )
+        ))
+        self.xrd.links.append(Link(
+            rel="http://joindiaspora.com/seed_location",
+            type_="text/html",
+            href=host
+        ))
+        self.xrd.links.append(Link(
+            rel="http://joindiaspora.com/guid",
+            type_="text/html",
+            href=guid
+        ))
+        self.xrd.links.append(Link(
+            rel="http://webfinger.net/rel/profile-page",
+            type_="text/html",
+            href="%s/u/%s" % (
+                host, username
+            )
+        ))
+        self.xrd.links.append(Link(
+            rel="http://schemas.google.com/g/2010#updates-from",
+            type_="application/atom+xml",
+            href="%s/public/%s.atom" % (
+                host, username
+            )
+        ))
+        # Base64 the key
+        # See https://wiki.diasporafoundation.org/Federation_Protocol_Overview#Diaspora_Public_Key
+        base64_key = b64encode(bytes(public_key, encoding="UTF-8")).decode("ascii")
+        self.xrd.links.append(Link(
+            rel="diaspora-public-key",
+            type_="RSA",
+            href=base64_key
+        ))

federation/tests/hostmeta/test_generators.py

@@ -1,5 +1,6 @@
 import pytest
-from federation.hostmeta.generators import generate_host_meta
+
+from federation.hostmeta.generators import generate_host_meta, generate_legacy_webfinger
 
 
 DIASPORA_HOSTMETA = """<?xml version="1.0" encoding="UTF-8"?>
@@ -8,6 +9,19 @@ DIASPORA_HOSTMETA = """<?xml version="1.0" encoding="UTF-8"?>
 </XRD>
 """
 
+DIASPORA_WEBFINGER = """<?xml version="1.0" encoding="UTF-8"?>
+<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
+  <Subject>acct:user@server.example</Subject>
+  <Alias>https://server.example/people/0123456789abcdef</Alias>
+  <Link href="https://server.example/hcard/users/user" rel="http://microformats.org/profile/hcard" type="text/html"/>
+  <Link href="https://server.example" rel="http://joindiaspora.com/seed_location" type="text/html"/>
+  <Link href="0123456789abcdef" rel="http://joindiaspora.com/guid" type="text/html"/>
+  <Link href="https://server.example/u/user" rel="http://webfinger.net/rel/profile-page" type="text/html"/>
+  <Link href="https://server.example/public/user.atom" rel="http://schemas.google.com/g/2010#updates-from" type="application/atom+xml"/>
+  <Link href="QUJDREVGPT0=" rel="diaspora-public-key" type="RSA"/>
+</XRD>
+"""
+
 
 class TestDiasporaHostMetaGenerator(object):
 
@@ -18,3 +32,20 @@ class TestDiasporaHostMetaGenerator(object):
     def test_generate_host_meta_requires_webfinger_host(self):
         with pytest.raises(KeyError):
             generate_host_meta("diaspora")
+
+
+class TestDiasporaWebFingerGenerator(object):
+
+    def test_generate_valid_webfinger(self):
+        webfinger = generate_legacy_webfinger(
+            "diaspora",
+            handle="user@server.example",
+            host="https://server.example",
+            guid="0123456789abcdef",
+            public_key="ABCDEF=="
+        )
+        assert webfinger.decode("UTF-8") == DIASPORA_WEBFINGER
+
+    def test_diaspora_webfinger_raises_on_missing_arguments(self):
+        with pytest.raises(TypeError):
+            generate_legacy_webfinger("diaspora")