Improve searching for private toots from URL (#14856)

* Improve searching for private toots from URL

Most of the time, when sharing toots, people use the toot URL rather than
the toot URI, which makes sense since it is the user-facing URL.

In Mastodon's case, the URL and URI are different, and Mastodon does not
have an index on URL, which means searching a private toot by URL is done
with a slow query that will only succeed for very recent toots.

This change gets rid of the slow query, and attempts to guess the URI from
URL instead, as Mastodon's are predictable.

* Add tests

* Only return status with guessed uri if url matches

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/services/resolve_url_service.rb

@@ -34,7 +34,17 @@ class ResolveURLService < BaseService
 
     # It may happen that the resource is a private toot, and thus not fetchable,
     # but we can return the toot if we already know about it.
-    status = Status.find_by(uri: @url) || Status.find_by(url: @url)
+    scope = Status.where(uri: @url)
+
+    # We don't have an index on `url`, so try guessing the `uri` from `url`
+    parsed_url = Addressable::URI.parse(@url)
+    parsed_url.path.match(%r{/@(?<username>#{Account::USERNAME_RE})/(?<status_id>[0-9]+)\Z}) do |matched|
+      parsed_url.path = "/users/#{matched[:username]}/statuses/#{matched[:status_id]}"
+      scope = scope.or(Status.where(uri: parsed_url.to_s, url: @url))
+    end
+
+    status = scope.first
+
     authorize_with @on_behalf_of, status, :show? unless status.nil?
     status
   rescue Mastodon::NotPermittedError

spec/services/resolve_url_service_spec.rb

@@ -15,5 +15,102 @@ describe ResolveURLService, type: :service do
 
       expect(subject.call(url)).to be_nil
     end
+
+    context 'searching for a remote private status' do
+      let(:account)  { Fabricate(:account) }
+      let(:poster)   { Fabricate(:account, domain: 'example.com') }
+      let(:url)      { 'https://example.com/@foo/42' }
+      let(:uri)      { 'https://example.com/users/foo/statuses/42' }
+      let!(:status)  { Fabricate(:status, url: url, uri: uri, account: poster, visibility: :private) }
+
+      before do
+        stub_request(:get, url).to_return(status: 404) if url.present?
+        stub_request(:get, uri).to_return(status: 404)
+      end
+
+      context 'when the account follows the poster' do
+        before do
+          account.follow!(poster)
+        end
+
+        context 'when the status uses Mastodon-style URLs' do
+          let(:url) { 'https://example.com/@foo/42' }
+          let(:uri) { 'https://example.com/users/foo/statuses/42' }
+
+          it 'returns status by url' do
+            expect(subject.call(url, on_behalf_of: account)).to eq(status)
+          end
+
+          it 'returns status by uri' do
+            expect(subject.call(uri, on_behalf_of: account)).to eq(status)
+          end
+        end
+
+        context 'when the status uses pleroma-style URLs' do
+          let(:url) { nil }
+          let(:uri) { 'https://example.com/objects/0123-456-789-abc-def' }
+
+          it 'returns status by uri' do
+            expect(subject.call(uri, on_behalf_of: account)).to eq(status)
+          end
+        end
+      end
+
+      context 'when the account does not follow the poster' do
+        context 'when the status uses Mastodon-style URLs' do
+          let(:url) { 'https://example.com/@foo/42' }
+          let(:uri) { 'https://example.com/users/foo/statuses/42' }
+
+          it 'does not return the status by url' do
+            expect(subject.call(url, on_behalf_of: account)).to be_nil
+          end
+
+          it 'does not return the status by uri' do
+            expect(subject.call(uri, on_behalf_of: account)).to be_nil
+          end
+        end
+
+        context 'when the status uses pleroma-style URLs' do
+          let(:url) { nil }
+          let(:uri) { 'https://example.com/objects/0123-456-789-abc-def' }
+
+          it 'returns status by uri' do
+            expect(subject.call(uri, on_behalf_of: account)).to be_nil
+          end
+        end
+      end
+    end
+
+    context 'searching for a local private status' do
+      let(:account) { Fabricate(:account) }
+      let(:poster)  { Fabricate(:account) }
+      let!(:status) { Fabricate(:status, account: poster, visibility: :private) }
+      let(:url)     { ActivityPub::TagManager.instance.url_for(status) }
+      let(:uri)     { ActivityPub::TagManager.instance.uri_for(status) }
+
+      context 'when the account follows the poster' do
+        before do
+          account.follow!(poster)
+        end
+
+        it 'returns status by url' do
+          expect(subject.call(url, on_behalf_of: account)).to eq(status)
+        end
+
+        it 'returns status by uri' do
+          expect(subject.call(uri, on_behalf_of: account)).to eq(status)
+        end
+      end
+
+      context 'when the account does not follow the poster' do
+        it 'does not return the status by url' do
+          expect(subject.call(url, on_behalf_of: account)).to be_nil
+        end
+
+        it 'does not return the status by uri' do
+          expect(subject.call(uri, on_behalf_of: account)).to be_nil
+        end
+      end
+    end
   end
 end