add Discovery class for discovery-logic

lib/diaspora_federation/discovery/discovery.rb

@@ -0,0 +1,77 @@
+module DiasporaFederation
+  module Discovery
+    # This class contains the logic to fetch all data for the given handle
+    class Discovery
+      include DiasporaFederation::Logging
+
+      # @return [String] the handle of the account
+      attr_reader :handle
+
+      # @param [String] account the diaspora handle to discover
+      def initialize(account)
+        @handle = clean_handle(account)
+      end
+
+      # fetch all metadata for the account
+      def fetch
+        logger.info "Fetch data for #{handle}"
+
+        unless handle == clean_handle(webfinger.acct_uri)
+          raise DiscoveryError, "Handle does not match: Wanted #{handle} but got #{clean_handle(webfinger.acct_uri)}"
+        end
+
+        discovery_data_hash
+      end
+
+      private
+
+      def clean_handle(account)
+        account.strip.sub("acct:", "").to_s.downcase
+      end
+
+      def get(url, http_fallback=false)
+        logger.info "Fetching #{url} for #{handle}"
+        response = Fetcher.get(url)
+        raise "Failed to fetch #{url}: #{response.status}" unless response.success?
+        response.body
+      rescue => e
+        if http_fallback && url.start_with?("https://")
+          logger.warn "Retry with http: #{url} for #{handle}: #{e.class}: #{e.message}"
+          url.sub!("https://", "http://")
+          retry
+        else
+          raise DiscoveryError, "Failed to fetch #{url} for #{handle}: #{e.class}: #{e.message}"
+        end
+      end
+
+      def host_meta_url
+        domain = handle.split("@")[1]
+        "https://#{domain}/.well-known/host-meta"
+      end
+
+      def legacy_webfinger_url_from_host_meta
+        # this tries the xrd url with https first, then falls back to http
+        host_meta = HostMeta.from_xml get(host_meta_url, true)
+        host_meta.webfinger_template_url.gsub("{uri}", "acct:#{handle}")
+      end
+
+      def webfinger
+        @webfinger ||= WebFinger.from_xml get(legacy_webfinger_url_from_host_meta)
+      end
+
+      def hcard
+        @hcard ||= HCard.from_html get(webfinger.hcard_url)
+      end
+
+      def discovery_data_hash
+        hcard_hash = hcard.to_h.expect(:guid, :serialized_public_key)
+        hcard_hash.merge(
+          guid:            hcard.guid || webfinger.guid,
+          public_key:      hcard.public_key || webfinger.public_key,
+          diaspora_handle: handle,
+          seed_url:        webfinger.seed_url
+        )
+      end
+    end
+  end
+end

lib/diaspora_federation/discovery/exceptions.rb

@@ -11,5 +11,9 @@ module DiasporaFederation
     # * if the html passed to {HCard.from_html} in some way is malformed, invalid or incomplete.
     class InvalidData < RuntimeError
     end
+
+    # Raised, if there is an error while discover a new person
+    class DiscoveryError < RuntimeError
+    end
   end
 end