Revision: 3510 Author: hans URL: http://bknr.net/trac/changeset/3510

Simple in-memory cache implemented.

U trunk/projects/pch/src/pch.erl

Modified: trunk/projects/pch/src/pch.erl =================================================================== --- trunk/projects/pch/src/pch.erl 2008-07-18 16:29:16 UTC (rev 3509) +++ trunk/projects/pch/src/pch.erl 2008-07-18 21:34:47 UTC (rev 3510) @@ -2,49 +2,40 @@ %%% http://www.rsaccon.com/2007/09/mochiweb-erlang-based-webserver-toolkit.html

-module(pch). --export([start/0, loop/1, stop/0]). +-export([start/0, loop/2, stop/0]). -define(DEFAULTS, [{name, ?MODULE}, {port, 9888}]).

start() -> - Loop = fun (Req) -> ?MODULE:loop(Req) end, + Cache = ets:new(table, [set, public]), + Loop = fun (Req) -> ?MODULE:loop(Req, Cache) end, mochiweb_http:start([{loop, Loop} | ?DEFAULTS]).

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

-backend_request(Req) -> +fetch_from_backend(Path) -> {ok, {{_Version, 200, _ReasonPhrase}, Headers, Body}} = - http:request("http://test.createrainforest.org" ++ Req:get(path)), - Req:respond({200, Headers, Body}). + http:request("http://test.createrainforest.org" ++ Path), + {ok, Headers, Body}.

-loop(Req) -> - "/" ++ Path = Req:get(path), +backend_request(Req, Cache) -> + Path = Req:get(path), + case ets:lookup(Cache, Path) of + [{Path, Headers, Body}] -> + io:format("cache HIT for ~p~n", [Path]), + Req:respond({200, Headers, Body}); + _ -> + io:format("cache MISS for ~p~n", [Path]), + {ok, Headers, Body} = fetch_from_backend(Path), + ets:insert(Cache, {Path, Headers, Body}), + Req:respond({200, Headers, Body}) + end. + +loop(Req, Cache) -> case Req:get(method) of - M when M =:= 'GET'; M =:= 'HEAD' -> - case Path of - "timer" -> - Response = Req:ok({"text/plain", chunked}), - timer(Response); - "static" -> - Req:ok({"text/plain", "static response"}); - "nodes" -> - Req:ok({"text/plain", - io_lib:format("~p~n", [nodes()])}); - "dump" -> - Req:ok({"text/plain", - io_lib:format("~p~n", [Req:dump()])}); -%% _ -> -%% Req:serve_file(Path) - _ -> - backend_request(Req) - end; + M when M =:= 'GET' -> + backend_request(Req, Cache); _ -> Req:respond({501, [], ""}) end. - -timer(Req) -> - Req:write_chunk(io_lib:format("The time is: ~p~n", - [calendar:local_time()])), - timer:sleep(1000), - timer(Req).