modules/federation: Add make_leave endpoint handler.

modules/Makefile.am

@@ -247,6 +247,7 @@ federation_federation_make_join_la_SOURCES = federation/make_join.cc
 federation_federation_send_join_la_SOURCES = federation/send_join.cc
 federation_federation_state_ids_la_SOURCES = federation/state_ids.cc
 federation_federation_state_la_SOURCES = federation/state.cc
+federation_federation_make_leave_la_SOURCES = federation/make_leave.cc
 
 federation_module_LTLIBRARIES = \
 	federation/federation_send.la \
@@ -261,6 +262,7 @@ federation_module_LTLIBRARIES = \
 	federation/federation_send_join.la \
 	federation/federation_state_ids.la \
 	federation/federation_state.la \
+	federation/federation_make_leave.la \
 	###
 
 ###############################################################################

modules/federation/make_leave.cc

@@ -0,0 +1,110 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+using namespace ircd;
+
+mapi::header
+IRCD_MODULE
+{
+	"Federation :Request a prototype for creating a leave event."
+};
+
+const string_view
+make_leave_description
+{R"(
+
+Sends a partial event to the remote with enough information for them to
+create a leave event 'in the blind' for one of their users.
+
+)"};
+
+resource
+make_leave_resource
+{
+	"/_matrix/federation/v1/make_leave/",
+	{
+		make_leave_description,
+		resource::DIRECTORY
+	}
+};
+
+resource::response
+get__make_leave(client &client,
+                const resource::request &request)
+{
+	if(request.parv.size() < 1)
+		throw m::NEED_MORE_PARAMS
+		{
+			"room_id path parameter required"
+		};
+
+	m::room::id::buf room_id
+	{
+		url::decode(request.parv[0], room_id)
+	};
+
+	if(request.parv.size() < 2)
+		throw m::NEED_MORE_PARAMS
+		{
+			"user_id path parameter required"
+		};
+
+	m::user::id::buf user_id
+	{
+		url::decode(request.parv[1], user_id)
+	};
+
+	uint64_t depth;
+	const m::event::id::buf prev_id
+	{
+		m::head(room_id, depth)
+	};
+
+	const json::value prev
+	{
+		prev_id
+	};
+
+	const json::value prevs[]
+	{
+		{ &prev, 1 }
+	};
+
+	thread_local char bufs[96_KiB];
+	mutable_buffer buf{bufs};
+
+	json::iov content, event, wrapper;
+	const json::iov::push push[]
+	{
+		{ event,    { "room_id",       room_id                   }},
+		{ event,    { "type",          "m.room.member"           }},
+		{ event,    { "state_key",     user_id                   }},
+		{ event,    { "depth",         int64_t(depth) + 1        }},
+		{ event,    { "membership",    "leave"                   }},
+		{ content,  { "membership",    "leave"                   }},
+		{ event,    { "prev_events",   { prevs, 1 }              }},
+		{ event,    { "content",       stringify(buf, content)   }},
+		{ wrapper,  { "event",         stringify(buf, event)     }},
+	};
+
+	return resource::response
+	{
+		client, wrapper
+	};
+}
+
+resource::method
+method_get
+{
+	make_leave_resource, "GET", get__make_leave,
+	{
+		method_get.VERIFY_ORIGIN
+	}
+};