Add support for Cowboy.

README.md

@@ -32,6 +32,13 @@ See
 to learn how to delegate incoming Mochiweb HTTP requests to the
 JSON-RPC service dispatcher.
 
+### Using Cowboy
+
+See
+[rfc4627\_jsonrpc\_cowboy.erl](http://tonyg.github.com/erlang-rfc4627/doc/rfc4627_jsonrpc_cowboy.html)
+to learn how to delegate incoming Cowboy HTTP requests to the
+JSON-RPC service dispatcher.
+
 ## Running the example test service that comes with the source code
 
 Included with the Erlang RFC4627 source code is a small Inets-based
@@ -88,6 +95,7 @@ contributions from others:
  - Eugene Volchek
  - Simon MacMullen
  - Andrey Khozov
+ - Erik Timan
 
 ## Copyright and Licence
 

ebin/rfc4627_jsonrpc.app

@@ -9,6 +9,7 @@
     rfc4627_jsonrpc_http,
     rfc4627_jsonrpc_inets,
     rfc4627_jsonrpc_mochiweb,
+    rfc4627_jsonrpc_cowboy,
     rfc4627_jsonrpc_registry
   ]},
   {registered, []},

src/rfc4627_jsonrpc_cowboy.erl

@@ -0,0 +1,113 @@
+%% JSON-RPC for Cowboy
+%%---------------------------------------------------------------------------
+%% @author Erik Timan <dev@timan.info>
+%% @author Tony Garnock-Jones <tonygarnockjones@gmail.com>
+%% @author LShift Ltd. <query@lshift.net>
+%% @copyright 2007-2010, 2011, 2012 Tony Garnock-Jones and 2007-2010 LShift Ltd.
+%% @license
+%%
+%% Permission is hereby granted, free of charge, to any person
+%% obtaining a copy of this software and associated documentation
+%% files (the "Software"), to deal in the Software without
+%% restriction, including without limitation the rights to use, copy,
+%% modify, merge, publish, distribute, sublicense, and/or sell copies
+%% of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be
+%% included in all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+%% EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+%% MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+%% NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+%% BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+%% ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+%% CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+%% SOFTWARE.
+%%---------------------------------------------------------------------------
+%%
+%% @reference the <a href="http://github.com/extend/cowboy/">Cowboy github page</a>
+%%
+%% @doc Support for serving JSON-RPC via Cowboy.
+%%
+%% Familiarity with writing Cowboy applications is assumed.
+%%
+%% == Basic Usage ==
+%%
+%% <ul>
+%% <li>Register your JSON-RPC services as usual.</li>
+%% <li>Decide on your `AliasPrefix' (see {@link rfc4627_jsonrpc_http:invoke_service_method/4}).</li>
+%% <li>When a Cowboy request arrives at your application, call {@link handle/2} with your `AliasPrefix' and the request.</li>
+%% </ul>
+%%
+%% It's as simple as that - if the request's URI path matches the
+%% `AliasPrefix', it will be decoded and the JSON-RPC service it names
+%% will be invoked.
+
+-module(rfc4627_jsonrpc_cowboy).
+
+-export([handle/2]).
+
+normalize(X) when is_atom(X) ->
+    string:to_lower(atom_to_list(X));
+normalize(X) when is_binary(X) ->
+    string:to_lower(binary_to_list(X));
+normalize(X) when is_list(X) ->
+    string:to_lower(X).
+
+%% @spec (string(), #http_req{}) -> no_match | {ok, #http_req{}}
+%%
+%% @doc If the request matches `AliasPrefix', the corresponding
+%% JSON-RPC service is invoked, and an `{ok, #http_req{}}' is returned;
+%% otherwise, `no_match' is returned.
+%%
+%% Call this function from your Cowboy HTTP handler's `handle'
+%% function, as follows:
+%%
+%% ```
+%% Req2 = case rfc4627_jsonrpc_cowboy:handle("/rpc", Req) of
+%%           no_match ->
+%%               handle_non_jsonrpc_request(Req);
+%%           {ok, Reponse} ->
+%%               Response
+%%       end
+%% '''
+%%
+%% where `handle_non_jsonrpc_request' does the obvious thing for
+%% non-JSON-RPC requests.
+handle(AliasPrefix, Req) ->
+    {BinaryPath, _} = cowboy_http_req:raw_path(Req),
+    Path = binary_to_list(BinaryPath),
+    {QSVals, _} = cowboy_http_req:qs_vals(Req),
+    QueryObj = {obj, [{binary_to_list(K), V} || {K,V} <- QSVals]},
+    {Hdrs, _} = cowboy_http_req:headers(Req),
+    HeaderObj = {obj, [{normalize(K), V} || {K,V} <- Hdrs]},
+    {PeerAddr, _} = cowboy_http_req:peer_addr(Req),
+    Peer = list_to_binary(inet_parse:ntoa(PeerAddr)),
+    {Method, _} = cowboy_http_req:method(Req),
+    RequestInfo = {obj, [{"http_method", list_to_binary(atom_to_list(Method))},
+                         {"http_query_parameters", QueryObj},
+                         {"http_headers", HeaderObj},
+                         {"remote_peername", Peer},
+                         {"scheme", <<"http">>}]},
+    {ok, Body, _} = cowboy_http_req:body(Req),
+
+    case rfc4627_jsonrpc_http:invoke_service_method(AliasPrefix,
+                                                    Path,
+                                                    RequestInfo,
+                                                    Body) of
+        no_match ->
+            no_match;
+        {ok, ResultEnc, ResponseInfo} ->
+            {obj, ResponseHeaderFields} =
+                rfc4627:get_field(ResponseInfo, "http_headers", {obj, []}),
+            StatusCode =
+                rfc4627:get_field(ResponseInfo, "http_status_code", 200),
+            Headers = [{list_to_binary(K), V} || {K,V} <- ResponseHeaderFields],
+            RespType = [{<<"Content-Type">>, rfc4627:mime_type()}],
+            cowboy_http_req:reply(StatusCode,
+                                  Headers ++ RespType,
+                                  ResultEnc,
+                                  Req)
+    end.