fetch unknown persons to generate url

app/models/person.rb

@@ -215,6 +215,12 @@ class Person < ActiveRecord::Base
     url_to "/receive/users/#{guid}"
   end
 
+  # @param path [String]
+  # @return [String]
+  def url_to(path)
+    local? ? AppConfig.url_to(path) : pod.url_to(path)
+  end
+
   def public_key_hash
     Base64.encode64(OpenSSL::Digest::SHA256.new(serialized_public_key).to_s)
   end
@@ -286,12 +292,6 @@ class Person < ActiveRecord::Base
 
   private
 
-  # @param path [String]
-  # @return [String]
-  def url_to(path)
-    local? ? AppConfig.url_to(path) : pod.url_to(path)
-  end
-
   def fix_profile
     logger.info "fix profile for account: #{diaspora_handle}"
     DiasporaFederation::Discovery::Discovery.new(diaspora_handle).fetch_and_save

config/initializers/diaspora_federation.rb

@@ -108,7 +108,7 @@ DiasporaFederation.configure do |config|
     end
 
     on :fetch_person_url_to do |diaspora_id, path|
-      Pod.joins(:people).find_by(people: {diaspora_handle: diaspora_id}).url_to(path)
+      Person.find_or_fetch_by_identifier(diaspora_id).url_to(path)
     end
 
     on :update_pod do |url, status|

spec/federation_callbacks_spec.rb

@@ -428,6 +428,26 @@ describe "diaspora federation callbacks" do
         DiasporaFederation.callbacks.trigger(:fetch_person_url_to, person.diaspora_handle, "/path/on/pod")
       ).to eq("https://#{pod.host}/path/on/pod")
     end
+
+    it "fetches an unknown user" do
+      pod = FactoryGirl.build(:pod)
+      person = FactoryGirl.build(:person, pod: pod)
+      expect(Person).to receive(:find_or_fetch_by_identifier).with(person.diaspora_handle).and_return(person)
+
+      expect(
+        DiasporaFederation.callbacks.trigger(:fetch_person_url_to, person.diaspora_handle, "/path/on/pod")
+      ).to eq("https://#{pod.host}/path/on/pod")
+    end
+
+    it "forwards the DiscoveryError" do
+      diaspora_id = FactoryGirl.generate(:diaspora_id)
+      expect(Person).to receive(:find_or_fetch_by_identifier).with(diaspora_id)
+        .and_raise(DiasporaFederation::Discovery::DiscoveryError)
+
+      expect {
+        DiasporaFederation.callbacks.trigger(:fetch_person_url_to, diaspora_id, "/path/on/pod")
+      }.to raise_error DiasporaFederation::Discovery::DiscoveryError
+    end
   end
 
   describe ":update_pod" do