modules/federation/get_missing_events: Implement get_missing_events handler.

modules/federation/get_missing_events.cc

@@ -10,44 +10,125 @@
 
 using namespace ircd;
 
-mapi::header IRCD_MODULE
+mapi::header
+IRCD_MODULE
 {
-	"federation missing events handler"
+	"Federation (undocumented) :Get missing events."
 };
 
-struct send
-:resource
-{
-	using resource::resource;
-}
+resource
 get_missing_events_resource
 {
 	"/_matrix/federation/v1/get_missing_events/",
 	{
-		"federation missing events handler",
+		"Federation (undocumented) missing events handler",
 		resource::DIRECTORY,
 	}
 };
 
+static resource::response get__missing_events(client &, const resource::request &);
+
+resource::method
+method_get
+{
+	get_missing_events_resource, "GET", get__missing_events,
+	{
+		method_get.VERIFY_ORIGIN
+	}
+};
+
+resource::method
+method_post
+{
+	get_missing_events_resource, "POST", get__missing_events,
+	{
+		method_post.VERIFY_ORIGIN
+	}
+};
+
+conf::item<size_t>
+max_limit
+{
+	{ "name",     "ircd.federation.missing_events.max_limit" },
+	{ "default",  128L                                       }
+};
+
+conf::item<size_t>
+max_goose
+{
+	{ "name",     "ircd.federation.missing_events.max_goose" },
+	{ "default",  512L                                       }
+};
+
 resource::response
-handle_get(client &client,
-           const resource::request &request)
+get__missing_events(client &client,
+                    const resource::request &request)
 {
 	m::room::id::buf room_id
 	{
 		url::decode(request.parv[0], room_id)
 	};
 
+	const auto limit
+	{
+		request["limit"]?
+			std::min(lex_cast<size_t>(request["limit"]), size_t(max_limit)):
+			size_t(max_limit)
+	};
+
+	const auto min_depth
+	{
+		request["min_depth"]?
+			lex_cast<uint64_t>(request["min_depth"]):
+			0
+	};
+
+	const json::array &earliest
+	{
+		request["earliest_events"]
+	};
+
+	const json::array &latest
+	{
+		request["latest"]
+	};
+
+	const auto in_latest
+	{
+		[&latest](const auto &event_id)
+		{
+			return end(latest) != std::find_if(begin(latest), end(latest), [&event_id]
+			(const auto &latest)
+			{
+				return event_id == unquote(latest);
+			});
+		}
+	};
+
+	std::vector<std::string> ret;
+	ret.reserve(limit);
+	size_t goose{0};
+	for(const auto &event_id : earliest)
+	{
+		m::room::messages it
+		{
+			room_id, unquote(event_id)
+		};
+
+		for(; it && ret.size() < limit && goose < size_t(max_goose); ++it, ++goose)
+		{
+			const m::event &event{*it};
+			ret.emplace_back(json::strung{event});
+			if(in_latest(at<"event_id"_>(event)))
+				break;
+		}
+	}
+
 	return resource::response
 	{
-		client, http::NOT_FOUND
+		client, json::members
+		{
+			{ "events", json::strung { ret.data(), ret.data() + ret.size() } }
+		}
 	};
 }
-
-resource::method method_get
-{
-	get_missing_events_resource, "GET", handle_get,
-	{
-		method_get.VERIFY_ORIGIN
-	}
-};