From f93ad3d816c127833898a6d8fa4d77f5c73329dc Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Tue, 7 Apr 2020 10:37:24 -0700
Subject: [PATCH] modules/key/query: Implement federation 3.3.2.1 key query GET
 handler.

---
 modules/key/query.cc | 113 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 109 insertions(+), 4 deletions(-)

diff --git a/modules/key/query.cc b/modules/key/query.cc
index 1f844d436..3ddd2a6ea 100644
--- a/modules/key/query.cc
+++ b/modules/key/query.cc
@@ -1,15 +1,120 @@
-// Matrix Construct
+// The Construct
 //
-// Copyright (C) Matrix Construct Developers, Authors & Contributors
-// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 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.
 
+namespace ircd::m
+{
+	static resource::response handle_key_query_get(client &, const resource::request &);
+	extern resource::method key_query_get;
+
+	extern resource key_query_resource;
+}
+
 ircd::mapi::header
 IRCD_MODULE
 {
-	"Federation 2.3.1.2 :Querying Keys Through Another Server"
+	"Federation 3.3.2 :Querying Keys Through Another Server"
 };
+
+decltype(ircd::m::key_query_resource)
+ircd::m::key_query_resource
+{
+	"/_matrix/key/v2/query/",
+	{
+		"federation 3.3.2",
+		resource::DIRECTORY,
+	}
+};
+
+decltype(ircd::m::key_query_get)
+ircd::m::key_query_get
+{
+	key_query_resource, "GET", handle_key_query_get
+};
+
+ircd::m::resource::response
+ircd::m::handle_key_query_get(client &client,
+                              const m::resource::request &request)
+{
+	if(request.parv.size() < 1)
+		throw m::NEED_MORE_PARAMS
+		{
+			"serverName path parameter required"
+		};
+
+	char server_name_buf[rfc3986::DOMAIN_BUFSIZE];
+	const auto server_name
+	{
+		url::decode(server_name_buf, request.parv[0])
+	};
+
+	char key_id_buf[64];
+	const auto key_id
+	{
+		request.parv.size() > 1?
+			url::decode(key_id_buf, request.parv[1]):
+			string_view{}
+	};
+
+	const time_t minimum_valid_until_ts
+	{
+		request.query.get<time_t>("minimum_valid_until_ts", ircd::time<milliseconds>())
+	};
+
+	if(key_id)
+	{
+		const auto respond{[&client]
+		(const json::object &keys)
+		{
+			resource::response
+			{
+				client, keys
+			};
+		}};
+
+		if(!keys::cache::get(server_name, key_id, respond))
+			throw m::NOT_FOUND
+			{
+				"Key '%s' from server '%s' is not cached by this server",
+				key_id,
+				server_name,
+			};
+
+		return {}; // responded from closure
+	}
+
+	resource::response::chunked response
+	{
+		client, http::OK
+	};
+
+	json::stack out
+	{
+		response.buf, response.flusher()
+	};
+
+	json::stack::object top{out};
+	json::stack::array server_keys
+	{
+		top, "server_keys"
+	};
+
+	keys::cache::for_each(server_name, [&server_keys, &minimum_valid_until_ts]
+	(const m::keys &keys)
+	{
+		// Condition ignored to match synapse behavior.
+		if((false) && json::get<"valid_until_ts"_>(keys) < minimum_valid_until_ts)
+			return true;
+
+		server_keys.append(keys.source);
+		return true;
+	});
+
+	return {};
+}