ircd::resource: Add permanent redirect device.

include/ircd/resource/redirect.h

@@ -0,0 +1,41 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2019 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.
+
+#pragma once
+#define HAVE_IRCD_RESOURCE_REDIRECT_H
+
+struct ircd::resource::redirect
+{
+	struct permanent; // 308
+};
+
+/// This is a pseudo-resource that listens on `old_path` and responds with
+/// a 308 Permanent Redirect. The Location header replaces old_path with
+/// new_path, preserving anything in the URI after the replacement. This
+/// resource responds to all of the methods listed as instances.
+struct ircd::resource::redirect::permanent
+:resource
+{
+	string_view new_path;
+	method _options;
+	method _trace;
+	method _head;
+	method _get;
+	method _put;
+	method _post;
+	method _patch;
+	method _delete;
+
+	response handler(client &, const request &);
+
+	permanent(const string_view &old_path,
+	          const string_view &new_path,
+	          struct opts);
+};

include/ircd/resource/resource.h

@@ -28,6 +28,7 @@ struct ircd::resource
 	struct method;
 	struct request;
 	struct response;
+	struct redirect;
 
 	static log::log log;
 	static std::map<string_view, resource *, iless> resources;
@@ -53,6 +54,7 @@ struct ircd::resource
 #include "method.h"
 #include "request.h"
 #include "response.h"
+#include "redirect.h"
 
 enum ircd::resource::flag
 :uint

ircd/resource.cc

@@ -8,6 +8,11 @@
 // copyright notice and this permission notice is present in all copies. The
 // full license for this software is available in the LICENSE file.
 
+///////////////////////////////////////////////////////////////////////////////
+//
+// resource/resource.h
+//
+
 decltype(ircd::resource::log)
 ircd::resource::log
 {
@@ -1163,3 +1168,85 @@ ircd::resource::response::response(client &client,
 
 	assert(written == size(head.completed()));
 }
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// resource/redirect.h
+//
+
+//
+// redirect::permanent::permanent
+//
+
+ircd::resource::redirect::permanent::permanent(const string_view &old_path,
+                                               const string_view &new_path,
+                                               struct opts opts)
+:resource
+{
+	old_path, std::move(opts)
+}
+,new_path
+{
+	new_path
+}
+,_options
+{
+	*this, "OPTIONS", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_trace
+{
+	*this, "TRACE", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_head
+{
+	*this, "HEAD", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_get
+{
+	*this, "GET", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_put
+{
+	*this, "PUT", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_post
+{
+	*this, "POST", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_patch
+{
+	*this, "PATCH", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+,_delete
+{
+	*this, "DELETE", std::bind(&permanent::handler, this, ph::_1, ph::_2)
+}
+{
+}
+
+ircd::resource::response
+ircd::resource::redirect::permanent::handler(client &client,
+                                             const request &request)
+{
+	thread_local char buf[response::HEAD_BUF_SZ];
+
+	const string_view postfix
+	{
+		lstrip(request.head.uri, this->path)
+	};
+
+	const string_view location{fmt::sprintf
+	{
+		buf, "%s/%s",
+		rstrip(this->new_path, '/'),
+		lstrip(postfix, '/')
+	}};
+
+	return response
+	{
+		client, {}, {}, http::MOVED_PERMANENTLY,
+		{
+			http::header { "Location", location }
+		}
+	};
+}