%% Copyright (c) 2011-2013, Loïc Hoguin <[email protected]>
%%
%% 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 appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
%% @doc Routing middleware.
%%
%% Resolve the handler to be used for the request based on the
%% routing information found in the <em>dispatch</em> environment value.
%% When found, the handler module and associated data are added to
%% the environment as the <em>handler</em> and <em>handler_opts</em> values
%% respectively.
%%
%% If the route cannot be found, processing stops with either
%% a 400 or a 404 reply.
-module(cowboy_router).
-behaviour(cowboy_middleware).
-export([compile/1]).
-export([execute/2]).
-type bindings() :: [{atom(), binary()}].
-type tokens() :: [binary()].
-export_type([bindings/0]).
-export_type([tokens/0]).
-type constraints() :: [].
-export_type([constraints/0]).
-type route_match() :: binary() | string().
-type route_path() :: {Path::route_match(), Handler::module(), Opts::any()}
| {Path::route_match(), constraints(), Handler::module(), Opts::any()}.
-type route_rule() :: {Host::route_match(), Paths::[route_path()]}
| {Host::route_match(), constraints(), Paths::[route_path()]}.
-opaque routes() :: [route_rule()].
-export_type([routes/0]).
-type dispatch_match() :: '_' | <<_:8>> | [binary() | '_' | '...' | atom()].
-type dispatch_path() :: {dispatch_match(), module(), any()}.
-type dispatch_rule() :: {Host::dispatch_match(), Paths::[dispatch_path()]}.
-opaque dispatch_rules() :: [dispatch_rule()].
-export_type([dispatch_rules/0]).
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-endif.
%% @doc Compile a list of routes into the dispatch format used
%% by Cowboy's routing.
-spec compile(routes()) -> dispatch_rules().
compile(Routes) ->
compile(Routes, []).
compile([], Acc) ->
lists:reverse(Acc);
compile([{Host, Paths}|Tail], Acc) ->
compile([{Host, [], Paths}|Tail], Acc);
compile([{HostMatch, Constraints, Paths}|Tail], Acc) ->
HostRules = case HostMatch of
'_' -> '_';
_ -> compile_host(HostMatch)
end,
PathRules = compile_paths(Paths, []),
Hosts = case HostRules of
'_' -> [{'_', Constraints, PathRules}];
_ -> [{R, Constraints, PathRules} || R <- HostRules]
end,
compile(Tail, Hosts ++ Acc).
compile_host(HostMatch) when is_list(HostMatch) ->
compile_host(unicode:characters_to_binary(HostMatch));
compile_host(HostMatch) when is_binary(HostMatch) ->
compile_rules(HostMatch, $., [], [], <<>>).
compile_paths([], Acc) ->
lists:reverse(Acc);
compile_paths([{PathMatch, Handler, Opts}|Tail], Acc) ->
compile_paths([{PathMatch, [], Handler, Opts}|Tail], Acc);
compile_paths([{PathMatch, Constraints, Handler, Opts}|Tail], Acc)
when is_list(PathMatch) ->
compile_paths([{unicode:characters_to_binary(PathMatch),
Constraints, Handler, Opts}|Tail], Acc);
compile_paths([{'_', Constraints, Handler, Opts}|Tail], Acc) ->
compile_paths(Tail, [{'_', Constraints, Handler, Opts}] ++ Acc);
compile_paths([{<< $/, PathMatch/binary >>, Constraints, Handler, Opts}|Tail],
Acc) ->
PathRules = compile_rules(PathMatch, $/, [], [], <<>>),
Paths = [{lists:reverse(R), Constraints, Handler, Opts} || R <- PathRules],
compile_paths(Tail, Paths ++ Acc).
compile_rules(<<>>, _, Segments, Rules, <<>>) ->
[Segments|Rules];
compile_rules(<<>>, _, Segments, Rules, Acc) ->
[[Acc|Segments]|Rules];
compile_rules(<< S, Rest/binary >>, S, Segments, Rules, <<>>) ->
compile_rules(Rest, S, Segments, Rules, <<>>);
compile_rules(<< S, Rest/binary >>, S, Segments, Rules, Acc) ->
compile_rules(Rest, S, [Acc|Segments], Rules, <<>>);
compile_rules(<< $:, Rest/binary >>, S, Segments, Rules, <<>>) ->
{NameBin, Rest2} = compile_binding(Rest, S, <<>>),
Name = binary_to_atom(NameBin, utf8),
compile_rules(Rest2, S, Segments, Rules, Name);
compile_rules(<< $:, _/binary >>, _, _, _, _) ->
erlang:error(badarg);
compile_rules(<< $[, $., $., $., $], Rest/binary >>, S, Segments, Rules, Acc)
when Acc =:= <<>> ->
compile_rules(Rest, S, ['...'|Segments], Rules, Acc);
compile_rules(<< $[, $., $., $., $], Rest/binary >>, S, Segments, Rules, Acc) ->
compile_rules(Rest, S, ['...', Acc|Segments], Rules, Acc);
compile_rules(<< $[, S, Rest/binary >>, S, Segments, Rules, Acc) ->
compile_brackets(Rest, S, [Acc|Segments], Rules);
compile_rules(<< $[, Rest/binary >>, S, Segments, Rules, <<>>) ->
compile_brackets(Rest, S, Segments, Rules);
%% Open bracket in the middle of a segment.
compile_rules(<< $[, _/binary >>, _, _, _, _) ->
erlang:error(badarg);
%% Missing an open bracket.
compile_rules(<< $], _/binary >>, _, _, _, _) ->
erlang:error(badarg);
compile_rules(<< C, Rest/binary >>, S, Segments, Rules, Acc) ->
compile_rules(Rest, S, Segments, Rules, << Acc/binary, C >>).
%% Everything past $: until $. or $[ or $] or end of binary
%% is the binding name.
compile_binding(<<>>, _, <<>>) ->
erlang:error(badarg);
compile_binding(Rest = <<>>, _, Acc) ->
{Acc, Rest};
compile_binding(Rest = << C, _/binary >>, S, Acc)
when C =:= S; C =:= $[; C =:= $] ->
{Acc, Rest};
compile_binding(<< C, Rest/binary >>, S, Acc) ->
compile_binding(Rest, S, << Acc/binary, C >>).
compile_brackets(Rest, S, Segments, Rules) ->
{Bracket, Rest2} = compile_brackets_split(Rest, <<>>, 0),
Rules1 = compile_rules(Rest2, S, Segments, [], <<>>),
Rules2 = compile_rules(<< Bracket/binary, Rest2/binary >>,
S, Segments, [], <<>>),
Rules ++ Rules2 ++ Rules1.
%% Missing a close bracket.
compile_brackets_split(<<>>, _, _) ->
erlang:error(badarg);
%% Make sure we don't confuse the closing bracket we're looking for.
compile_brackets_split(<< C, Rest/binary >>, Acc, N) when C =:= $[ ->
compile_brackets_split(Rest, << Acc/binary, C >>, N + 1);
compile_brackets_split(<< C, Rest/binary >>, Acc, N) when C =:= $], N > 0 ->
compile_brackets_split(Rest, << Acc/binary, C >>, N - 1);
%% That's the right one.
compile_brackets_split(<< $], Rest/binary >>, Acc, 0) ->
{Acc, Rest};
compile_brackets_split(<< C, Rest/binary >>, Acc, N) ->
compile_brackets_split(Rest, << Acc/binary, C >>, N).
%% @private
-spec execute(Req, Env)
-> {ok, Req, Env} | {error, 400 | 404, Req}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
execute(Req, Env) ->
{_, Dispatch} = lists:keyfind(dispatch, 1, Env),
[Host, Path] = cowboy_req:get([host, path], Req),
case match(Dispatch, Host, Path) of
{ok, Handler, HandlerOpts, Bindings, HostInfo, PathInfo} ->
Req2 = cowboy_req:set_bindings(HostInfo, PathInfo, Bindings, Req),
{ok, Req2, [{handler, Handler}, {handler_opts, HandlerOpts}|Env]};
{error, notfound, host} ->
{error, 400, Req};
{error, badrequest, path} ->
{error, 400, Req};
{error, notfound, path} ->
{error, 404, Req}
end.
%% Internal.
%% @doc Match hostname tokens and path tokens against dispatch rules.
%%
%% It is typically used for matching tokens for the hostname and path of
%% the request against a global dispatch rule for your listener.
%%
%% Dispatch rules are a list of <em>{Hostname, PathRules}</em> tuples, with
%% <em>PathRules</em> being a list of <em>{Path, HandlerMod, HandlerOpts}</em>.
%%
%% <em>Hostname</em> and <em>Path</em> are match rules and can be either the
%% atom <em>'_'</em>, which matches everything, `<<"*">>', which match the
%% wildcard path, or a list of tokens.
%%
%% Each token can be either a binary, the atom <em>'_'</em>,
%% the atom '...' or a named atom. A binary token must match exactly,
%% <em>'_'</em> matches everything for a single token, <em>'...'</em> matches
%% everything for the rest of the tokens and a named atom will bind the
%% corresponding token value and return it.
%%
%% The list of hostname tokens is reversed before matching. For example, if
%% we were to match "www.ninenines.eu", we would first match "eu", then
%% "ninenines", then "www". This means that in the context of hostnames,
%% the <em>'...'</em> atom matches properly the lower levels of the domain
%% as would be expected.
%%
%% When a result is found, this function will return the handler module and
%% options found in the dispatch list, a key-value list of bindings and
%% the tokens that were matched by the <em>'...'</em> atom for both the
%% hostname and path.
-spec match(dispatch_rules(), Host::binary() | tokens(), Path::binary())
-> {ok, module(), any(), bindings(),
HostInfo::undefined | tokens(),
PathInfo::undefined | tokens()}
| {error, notfound, host} | {error, notfound, path}
| {error, badrequest, path}.
match([], _, _) ->
{error, notfound, host};
%% If the host is '_' then there can be no constraints.
match([{'_', [], PathMatchs}|_Tail], _, Path) ->
match_path(PathMatchs, undefined, Path, []);
match([{HostMatch, _Constraints, PathMatchs}|Tail], Tokens, Path)
when is_list(Tokens) ->
case list_match(Tokens, HostMatch, []) of
false ->
match(Tail, Tokens, Path);
{true, Bindings, undefined} ->
match_path(PathMatchs, undefined, Path, Bindings);
{true, Bindings, HostInfo} ->
match_path(PathMatchs, lists:reverse(HostInfo),
Path, Bindings)
end;
match(Dispatch, Host, Path) ->
match(Dispatch, split_host(Host), Path).
-spec match_path([dispatch_path()],
HostInfo::undefined | tokens(), binary() | tokens(), bindings())
-> {ok, module(), any(), bindings(),
HostInfo::undefined | tokens(),
PathInfo::undefined | tokens()}
| {error, notfound, path} | {error, badrequest, path}.
match_path([], _, _, _) ->
{error, notfound, path};
%% If the path is '_' then there can be no constraints.
match_path([{'_', [], Handler, Opts}|_Tail], HostInfo, _, Bindings) ->
{ok, Handler, Opts, Bindings, HostInfo, undefined};
match_path([{<<"*">>, _Constraints, Handler, Opts}|_Tail], HostInfo, <<"*">>, Bindings) ->
{ok, Handler, Opts, Bindings, HostInfo, undefined};
match_path([{PathMatch, _Constraints, Handler, Opts}|Tail], HostInfo, Tokens,
Bindings) when is_list(Tokens) ->
case list_match(Tokens, PathMatch, []) of
false ->
match_path(Tail, HostInfo, Tokens, Bindings);
{true, PathBinds, PathInfo} ->
{ok, Handler, Opts, Bindings ++ PathBinds, HostInfo, PathInfo}
end;
match_path(_Dispatch, _HostInfo, badrequest, _Bindings) ->
{error, badrequest, path};
match_path(Dispatch, HostInfo, Path, Bindings) ->
match_path(Dispatch, HostInfo, split_path(Path), Bindings).
%% @doc Split a hostname into a list of tokens.
-spec split_host(binary()) -> tokens().
split_host(Host) ->
split_host(Host, []).
split_host(Host, Acc) ->
case binary:match(Host, <<".">>) of
nomatch when Host =:= <<>> ->
Acc;
nomatch ->
[Host|Acc];
{Pos, _} ->
<< Segment:Pos/binary, _:8, Rest/bits >> = Host,
false = byte_size(Segment) == 0,
split_host(Rest, [Segment|Acc])
end.
%% @doc Split a path into a list of path segments.
%%
%% Following RFC2396, this function may return path segments containing any
%% character, including <em>/</em> if, and only if, a <em>/</em> was escaped
%% and part of a path segment.
-spec split_path(binary()) -> tokens().
split_path(<< $/, Path/bits >>) ->
split_path(Path, []);
split_path(_) ->
badrequest.
split_path(Path, Acc) ->
try
case binary:match(Path, <<"/">>) of
nomatch when Path =:= <<>> ->
lists:reverse([cowboy_http:urldecode(S) || S <- Acc]);
nomatch ->
lists:reverse([cowboy_http:urldecode(S) || S <- [Path|Acc]]);
{Pos, _} ->
<< Segment:Pos/binary, _:8, Rest/bits >> = Path,
split_path(Rest, [Segment|Acc])
end
catch
error:badarg ->
badrequest
end.
-spec list_match(tokens(), dispatch_match(), bindings())
-> {true, bindings(), undefined | tokens()} | false.
%% Atom '...' matches any trailing path, stop right now.
list_match(List, ['...'], Binds) ->
{true, Binds, List};
%% Atom '_' matches anything, continue.
list_match([_E|Tail], ['_'|TailMatch], Binds) ->
list_match(Tail, TailMatch, Binds);
%% Both values match, continue.
list_match([E|Tail], [E|TailMatch], Binds) ->
list_match(Tail, TailMatch, Binds);
%% Bind E to the variable name V and continue.
list_match([E|Tail], [V|TailMatch], Binds) when is_atom(V) ->
list_match(Tail, TailMatch, [{V, E}|Binds]);
%% Match complete.
list_match([], [], Binds) ->
{true, Binds, undefined};
%% Values don't match, stop.
list_match(_List, _Match, _Binds) ->
false.
%% Tests.
-ifdef(TEST).
compile_test_() ->
%% {Routes, Result}
Tests = [
%% Match any host and path.
{[{'_', [{'_', h, o}]}],
[{'_', [], [{'_', [], h, o}]}]},
{[{"cowboy.example.org",
[{"/", ha, oa}, {"/path/to/resource", hb, ob}]}],
[{[<<"org">>, <<"example">>, <<"cowboy">>], [], [
{[], [], ha, oa},
{[<<"path">>, <<"to">>, <<"resource">>], [], hb, ob}]}]},
{[{'_', [{"/path/to/resource/", h, o}]}],
[{'_', [], [{[<<"path">>, <<"to">>, <<"resource">>], [], h, o}]}]},
{[{"cowboy.example.org.", [{'_', h, o}]}],
[{[<<"org">>, <<"example">>, <<"cowboy">>], [], [{'_', [], h, o}]}]},
{[{".cowboy.example.org", [{'_', h, o}]}],
[{[<<"org">>, <<"example">>, <<"cowboy">>], [], [{'_', [], h, o}]}]},
{[{":subdomain.example.org", [{"/hats/:name/prices", h, o}]}],
[{[<<"org">>, <<"example">>, subdomain], [], [
{[<<"hats">>, name, <<"prices">>], [], h, o}]}]},
{[{"ninenines.:_", [{"/hats/:_", h, o}]}],
[{['_', <<"ninenines">>], [], [{[<<"hats">>, '_'], [], h, o}]}]},
{[{"[www.]ninenines.eu",
[{"/horses", h, o}, {"/hats/[page/:number]", h, o}]}], [
{[<<"eu">>, <<"ninenines">>], [], [
{[<<"horses">>], [], h, o},
{[<<"hats">>], [], h, o},
{[<<"hats">>, <<"page">>, number], [], h, o}]},
{[<<"eu">>, <<"ninenines">>, <<"www">>], [], [
{[<<"horses">>], [], h, o},
{[<<"hats">>], [], h, o},
{[<<"hats">>, <<"page">>, number], [], h, o}]}]},
{[{'_', [{"/hats/[page/[:number]]", h, o}]}], [{'_', [], [
{[<<"hats">>], [], h, o},
{[<<"hats">>, <<"page">>], [], h, o},
{[<<"hats">>, <<"page">>, number], [], h, o}]}]},
{[{"[...]ninenines.eu", [{"/hats/[...]", h, o}]}],
[{[<<"eu">>, <<"ninenines">>, '...'], [], [
{[<<"hats">>, '...'], [], h, o}]}]}
],
[{lists:flatten(io_lib:format("~p", [Rt])),
fun() -> Rs = compile(Rt) end} || {Rt, Rs} <- Tests].
split_host_test_() ->
%% {Host, Result}
Tests = [
{<<"">>, []},
{<<"*">>, [<<"*">>]},
{<<"cowboy.ninenines.eu">>,
[<<"eu">>, <<"ninenines">>, <<"cowboy">>]},
{<<"ninenines.eu">>,
[<<"eu">>, <<"ninenines">>]},
{<<"a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z">>,
[<<"z">>, <<"y">>, <<"x">>, <<"w">>, <<"v">>, <<"u">>, <<"t">>,
<<"s">>, <<"r">>, <<"q">>, <<"p">>, <<"o">>, <<"n">>, <<"m">>,
<<"l">>, <<"k">>, <<"j">>, <<"i">>, <<"h">>, <<"g">>, <<"f">>,
<<"e">>, <<"d">>, <<"c">>, <<"b">>, <<"a">>]}
],
[{H, fun() -> R = split_host(H) end} || {H, R} <- Tests].
split_path_test_() ->
%% {Path, Result, QueryString}
Tests = [
{<<"/">>, []},
{<<"/extend//cowboy">>, [<<"extend">>, <<>>, <<"cowboy">>]},
{<<"/users">>, [<<"users">>]},
{<<"/users/42/friends">>, [<<"users">>, <<"42">>, <<"friends">>]},
{<<"/users/a+b/c%21d">>, [<<"users">>, <<"a b">>, <<"c!d">>]}
],
[{P, fun() -> R = split_path(P) end} || {P, R} <- Tests].
match_test_() ->
Dispatch = [
{[<<"eu">>, <<"ninenines">>, '_', <<"www">>], [], [
{[<<"users">>, '_', <<"mails">>], [], match_any_subdomain_users, []}
]},
{[<<"eu">>, <<"ninenines">>], [], [
{[<<"users">>, id, <<"friends">>], [], match_extend_users_friends, []},
{'_', [], match_extend, []}
]},
{[var, <<"ninenines">>], [], [
{[<<"threads">>, var], [], match_duplicate_vars,
[we, {expect, two}, var, here]}
]},
{[ext, <<"erlang">>], [], [
{'_', [], match_erlang_ext, []}
]},
{'_', [], [
{[<<"users">>, id, <<"friends">>], [], match_users_friends, []},
{'_', [], match_any, []}
]}
],
%% {Host, Path, Result}
Tests = [
{<<"any">>, <<"/">>, {ok, match_any, [], []}},
{<<"www.any.ninenines.eu">>, <<"/users/42/mails">>,
{ok, match_any_subdomain_users, [], []}},
{<<"www.ninenines.eu">>, <<"/users/42/mails">>,
{ok, match_any, [], []}},
{<<"www.ninenines.eu">>, <<"/">>,
{ok, match_any, [], []}},
{<<"www.any.ninenines.eu">>, <<"/not_users/42/mails">>,
{error, notfound, path}},
{<<"ninenines.eu">>, <<"/">>,
{ok, match_extend, [], []}},
{<<"ninenines.eu">>, <<"/users/42/friends">>,
{ok, match_extend_users_friends, [], [{id, <<"42">>}]}},
{<<"erlang.fr">>, '_',
{ok, match_erlang_ext, [], [{ext, <<"fr">>}]}},
{<<"any">>, <<"/users/444/friends">>,
{ok, match_users_friends, [], [{id, <<"444">>}]}},
{<<"ninenines.fr">>, <<"/threads/987">>,
{ok, match_duplicate_vars, [we, {expect, two}, var, here],
[{var, <<"fr">>}, {var, <<"987">>}]}}
],
[{lists:flatten(io_lib:format("~p, ~p", [H, P])), fun() ->
{ok, Handler, Opts, Binds, undefined, undefined}
= match(Dispatch, H, P)
end} || {H, P, {ok, Handler, Opts, Binds}} <- Tests].
match_info_test_() ->
Dispatch = [
{[<<"eu">>, <<"ninenines">>, <<"www">>], [], [
{[<<"pathinfo">>, <<"is">>, <<"next">>, '...'], [], match_path, []}
]},
{[<<"eu">>, <<"ninenines">>, '...'], [], [
{'_', [], match_any, []}
]}
],
Tests = [
{<<"ninenines.eu">>, <<"/">>,
{ok, match_any, [], [], [], undefined}},
{<<"bugs.ninenines.eu">>, <<"/">>,
{ok, match_any, [], [], [<<"bugs">>], undefined}},
{<<"cowboy.bugs.ninenines.eu">>, <<"/">>,
{ok, match_any, [], [], [<<"cowboy">>, <<"bugs">>], undefined}},
{<<"www.ninenines.eu">>, <<"/pathinfo/is/next">>,
{ok, match_path, [], [], undefined, []}},
{<<"www.ninenines.eu">>, <<"/pathinfo/is/next/path_info">>,
{ok, match_path, [], [], undefined, [<<"path_info">>]}},
{<<"www.ninenines.eu">>, <<"/pathinfo/is/next/foo/bar">>,
{ok, match_path, [], [], undefined, [<<"foo">>, <<"bar">>]}}
],
[{lists:flatten(io_lib:format("~p, ~p", [H, P])), fun() ->
R = match(Dispatch, H, P)
end} || {H, P, R} <- Tests].
-endif.
