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clean up dispatcher api
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justin committed May 7, 2009
1 parent 65f24da commit af5164a
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Showing 4 changed files with 83 additions and 153 deletions.
4 changes: 2 additions & 2 deletions src/webmachine_decision_core.erl
View file
Expand Up @@ -52,7 +52,7 @@ respond(Code) ->
EndTime = now(),
case Code of
404 ->
ErrorHandler = webmachine_dispatcher:get_error_handler(),
{ok, ErrorHandler} = application:get_env(webmachine, error_handler),
Reason = {none, none, []},
ErrorHTML = ErrorHandler:render_error(Code, get(req), Reason),
wrcall({set_resp_body, ErrorHTML});
Expand Down Expand Up @@ -89,7 +89,7 @@ respond(Code, Headers) ->
respond(Code).

error_response(Code, Reason) ->
ErrorHandler = webmachine_dispatcher:get_error_handler(),
{ok, ErrorHandler} = application:get_env(webmachine, error_handler),
ErrorHTML = ErrorHandler:render_error(Code, get(req), Reason),
wrcall({set_resp_body, ErrorHTML}),
respond(Code).
Expand Down
210 changes: 75 additions & 135 deletions src/webmachine_dispatcher.erl
View file
@@ -1,6 +1,6 @@
%% @author Robert Ahrens <rahrens@basho.com>
%% @copyright 2008 Basho Technologies
%% @copyright 2007-2008 Basho Technologies
%% @author Justin Sheehy <justin@basho.com>
%% @copyright 2007-2009 Basho Technologies
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
Expand All @@ -14,159 +14,99 @@
%% See the License for the specific language governing permissions and
%% limitations under the License.

%% @doc gen_server for dispatching page requests from webmachine.
%% @doc Module for URL-dispatch by pattern matching.

-module(webmachine_dispatcher).
-author('Robert Ahrens <rahrens@basho.com>').
-behaviour(gen_server).
-author('Justin Sheehy <justin@basho.com>').

-export([dispatch/2]).

-define(SEPARATOR, $\/).
-define(MATCH_ALL, '*').

%% API
-export([start_link/0, start_link/1, stop/0, dispatch/1,
set_dispatch_list/1, get_dispatch_list/0]).
-export([set_error_handler/1, get_error_handler/0]).

%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).

-record(state, {dispatchlist=[], error_handler}).

%%====================================================================
%% API
%%====================================================================
%% @spec start_link() -> {ok,Pid} | ignore | {error,Error}
%% @doc Starts the dispatch server
start_link() ->
start_link([]).
start_link(DispatchList) when is_list(DispatchList) ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [DispatchList], []).

stop() ->
gen_server:cast(?MODULE, stop).

dispatch(Req) ->
gen_server:call(?MODULE, {dispatch, Req}).

set_dispatch_list(List) when is_list(List) ->
gen_server:cast(?MODULE, {set_dispatch_list, List}).

get_dispatch_list() ->
gen_server:call(?MODULE, get_dispatch_list).

set_error_handler(ErrorHandlerMod) when is_atom(ErrorHandlerMod) ->
gen_server:cast(?MODULE, {set_error_handler, ErrorHandlerMod}).

get_error_handler() ->
gen_server:call(?MODULE, get_error_handler).


%%====================================================================
%% gen_server callbacks
%%====================================================================

%% @spec init(Args) -> {ok, State} |
%% {ok, State, Timeout} |
%% ignore |
%% {stop, Reason}
%% @doc Initiates the server
init([DispatchList]) ->
{ok, #state{dispatchlist=DispatchList}}.

%% @spec %% handle_call(Request, From, State) -> {reply, Reply, State} |
%% {reply, Reply, State, Timeout} |
%% {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, Reply, State} |
%% {stop, Reason, State}
%% Description: Handling call messages
handle_call({dispatch, Req}, From, State) ->
spawn(fun() -> binding_dispatch(State#state.dispatchlist, Req, From) end),
{noreply, State};
handle_call(get_error_handler, _From, State) ->
{reply, State#state.error_handler, State};
handle_call(get_dispatch_list, _From, State) ->
{reply, State#state.dispatchlist, State}.

%% @spec handle_cast(Msg, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% @doc Handling cast messages
handle_cast(stop, State) ->
{stop, normal, State};
handle_cast({set_error_handler, ErrorHandlerMod}, State) ->
{noreply, State#state{error_handler=ErrorHandlerMod}};
handle_cast({set_dispatch_list, List}, State) when is_list(List) ->
{noreply, State#state{dispatchlist=List}}.

%% @spec handle_info(Info, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% @doc Handling all non call/cast messages
handle_info(_Info, State) ->
{noreply, State}.

%% @spec terminate(Reason, State) -> void()
%% @doc This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any necessary
%% cleaning up. When it returns, the gen_server terminates with Reason.
%% The return value is ignored.
terminate(_Reason, _State) ->
ok.

%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @doc Convert process state when code is changed

code_change(_OldVsn, State, _Extra) ->
{ok, State}.

%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
%% @spec dispatch(Path::string(), DispatchList::[matchterm()]) ->
%% dispterm() | dispfail()
%% @doc Interface for URL dispatching.
%% See also http://bitbucket.org/justin/webmachine/wiki/DispatchConfiguration
dispatch(PathAsString, DispatchList) ->
Path = string:tokens(PathAsString, [?SEPARATOR]),
% URIs that end with a trailing slash are implicitly one token
% "deeper" than we otherwise might think as we are "inside"
% a directory named by the last token.
ExtraDepth = case lists:last(PathAsString) == ?SEPARATOR of
true -> 1;
_ -> 0
end,
try_binding(DispatchList, Path, ExtraDepth).

%% @type matchterm() = {[pathterm()], matchmod(), matchopts()}.
% The dispatch configuration is a list of these terms, and the
% first one whose list of pathterms matches the input path is used.

%% @type pathterm() = '*' | string() | atom().
% A list of pathterms is matched against a '/'-separated input path.
% The '*' pathterm matches all remaining tokens.
% A string pathterm will match a token of exactly the same string.
% Any atom pathterm other than '*' will match any token and will
% create a binding in the result if a complete match occurs.

%% @type matchmod() = atom().
% This atom, if present in a successful matchterm, will appear in
% the resulting dispterm. In Webmachine this is used to name the
% resource module that will handle the matching request.

%% @type matchopts() = [term()].
% This term, if present in a successful matchterm, will appear in
% the resulting dispterm. In Webmachine this is used to provide
% arguments to the resource module handling the matching request.

%% @type dispterm() = {matchmod(), matchopts(), pathtokens(),
%% bindings(), approot(), stringpath()}.

%% @type pathtokens() = [pathtoken()].
% This is the list of tokens matched by a trailing '*' pathterm.

%% @type pathtoken() = string().

%% @type bindings() = [{bindingterm(),pathtoken()}].
% This is a proplist of bindings indicated by atom terms in the
% matching spec, bound to the matching tokens in the request path.

%% @type approot() = string().

%% @type stringpath() = string().
% This is the path portion matched by a trailing '*' pathterm.

%% @type dispfail() = {no_dispatch_match, pathtokens()}.

try_binding([], PathTokens, _) ->
{no_dispatch_match, PathTokens};
try_binding([{PathSchema, Mod, Props}|Rest], PathTokens, ExtraDepth) ->
case bind_path(PathSchema, PathTokens, [], 0) of
{ok, Remainder, Bindings, Depth} ->
{Mod, Props, Remainder, Bindings,
calculate_app_root(Depth + ExtraDepth), reconstitute(Remainder)};
fail ->
try_binding(Rest, PathTokens, ExtraDepth)
end.

bind_path([], [], Bindings, Depth) ->
{ok, [], Bindings, Depth};
bind_path([?MATCH_ALL], PathRest, Bindings, Depth) when is_list(PathRest) ->
{ok, PathRest, Bindings, Depth + length(PathRest)};
bind_path(_, [], _, _) ->
fail;
bind_path([Token|Rest], [Match|PathRest], Bindings, Depth) when is_atom(Token) ->
bind_path([Token|Rest],[Match|PathRest],Bindings,Depth) when is_atom(Token) ->
bind_path(Rest, PathRest, [{Token, Match}|Bindings], Depth + 1);
bind_path([Token|Rest], [Token|PathRest], Bindings, Depth) ->
bind_path(Rest, PathRest, Bindings, Depth + 1);
bind_path(_, _, _, _) ->
fail.

try_binding([], PathTokens, _) ->
{no_dispatch_match, PathTokens};
try_binding([{PathSchema, Mod, Props}|Rest], PathTokens, ExtraDepth) ->
case bind_path(PathSchema, PathTokens, [], 0) of
{ok, Remainder, Bindings, Depth} ->
{Mod, Props, Remainder, Bindings, calculate_app_root(Depth + ExtraDepth), reconstitute(Remainder)};
fail ->
try_binding(Rest, PathTokens, ExtraDepth)
end.

reconstitute([]) ->
"";
reconstitute(UnmatchedTokens) ->
string:join(UnmatchedTokens, [?SEPARATOR]).

binding_dispatch(DispatchList, Req, Client) ->
PathAsString = Req:path(),
Path = string:tokens(PathAsString, [?SEPARATOR]),
% URIs that end with a trailing slash are implicitly one token
% "deeper" than we otherwise might think as we are "inside"
% a directory named by the last token.
ExtraDepth = case lists:last(PathAsString) == ?SEPARATOR of
true -> 1;
_ -> 0
end,
gen_server:reply(Client, try_binding(DispatchList, Path, ExtraDepth)).
reconstitute([]) -> "";
reconstitute(UnmatchedTokens) -> string:join(UnmatchedTokens, [?SEPARATOR]).

calculate_app_root(1) ->
".";
calculate_app_root(1) -> ".";
calculate_app_root(N) when N > 1 ->
string:join(lists:duplicate(N, ".."), [?SEPARATOR]).
9 changes: 5 additions & 4 deletions src/webmachine_mochiweb.erl
View file
Expand Up @@ -39,18 +39,19 @@ start(Options) ->
_ ->
ignore
end,
webmachine_sup:start_dispatcher(DispatchList),
webmachine_dispatcher:set_error_handler(ErrorHandler),
application:set_env(webmachine, dispatch_list, DispatchList),
application:set_env(webmachine, error_handler, ErrorHandler),
mochiweb_http:start([{name, ?MODULE}, {loop, fun loop/1} | Options4]).

stop() ->
mochiweb_http:stop(?MODULE).

loop(MochiReq) ->
Req = webmachine:new_request(mochiweb, MochiReq),
case webmachine_dispatcher:dispatch(Req) of
{ok, DispatchList} = application:get_env(webmachine, dispatch_list),
case webmachine_dispatcher:dispatch(Req:path(), DispatchList) of
{no_dispatch_match, _UnmatchedPathTokens} ->
ErrorHandler = webmachine_dispatcher:get_error_handler(),
{ok, ErrorHandler} = application:get_env(webmachine, error_handler),
ErrorHTML = ErrorHandler:render_error(404, Req, {none, none, []}),
Req:append_to_response_body(ErrorHTML),
Req:send_response(404),
Expand Down
13 changes: 1 addition & 12 deletions src/webmachine_sup.erl
View file
Expand Up @@ -21,7 +21,7 @@
-behaviour(supervisor).

%% External exports
-export([start_link/0, upgrade/0, start_dispatcher/1, start_logger/1]).
-export([start_link/0, upgrade/0, start_logger/1]).
-export([start_perf_logger/1]).

%% supervisor callbacks
Expand All @@ -32,17 +32,6 @@
start_link() ->
supervisor:start_link({local, ?MODULE}, ?MODULE, []).

%% @spec stat_dispatcher([dispatch_tuple()]) -> ok
%% @doc Starts a supervised webmachine_dispatcher process to
%% handle dispatch based on the list of dispatch tuples.
%% See webmachine_dispatcher for the dispatch_tuple().
start_dispatcher(DispatchList) ->
ChildSpec =
{webmachine_dispatcher,
{webmachine_dispatcher, start_link, [DispatchList]},
permanent, 5000, worker, dynamic},
supervisor:start_child(?MODULE, ChildSpec).

start_logger(BaseDir) ->
LoggerModule =
case application:get_env(webmachine, webmachine_logger_module) of
Expand Down

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