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%% @author Bob Ippolito <bob@mochimedia.com>
%% @copyright 2007 Mochi Media, Inc.
%% @doc Utilities for parsing multipart/form-data.
-module(mochiweb_multipart).
-author('bob@mochimedia.com').
-export([parse_form/1, parse_form/2]).
-export([parse_multipart_request/2]).
-export([test/0]).
-define(CHUNKSIZE, 4096).
-record(mp, {state, boundary, length, buffer, callback, req}).
%% TODO: DOCUMENT THIS MODULE.
parse_form(Req) ->
parse_form(Req, fun default_file_handler/2).
parse_form(Req, FileHandler) ->
Callback = fun (Next) -> parse_form_outer(Next, FileHandler, []) end,
{_, _, Res} = parse_multipart_request(Req, Callback),
Res.
parse_form_outer(eof, _, Acc) ->
lists:reverse(Acc);
parse_form_outer({headers, H}, FileHandler, State) ->
{"form-data", H1} = proplists:get_value("content-disposition", H),
Name = proplists:get_value("name", H1),
Filename = proplists:get_value("filename", H1),
case Filename of
undefined ->
fun (Next) ->
parse_form_value(Next, {Name, []}, FileHandler, State)
end;
_ ->
ContentType = proplists:get_value("content-type", H),
Handler = FileHandler(Filename, ContentType),
fun (Next) ->
parse_form_file(Next, {Name, Handler}, FileHandler, State)
end
end.
parse_form_value(body_end, {Name, Acc}, FileHandler, State) ->
Value = binary_to_list(iolist_to_binary(lists:reverse(Acc))),
State1 = [{Name, Value} | State],
fun (Next) -> parse_form_outer(Next, FileHandler, State1) end;
parse_form_value({body, Data}, {Name, Acc}, FileHandler, State) ->
Acc1 = [Data | Acc],
fun (Next) -> parse_form_value(Next, {Name, Acc1}, FileHandler, State) end.
parse_form_file(body_end, {Name, Handler}, FileHandler, State) ->
Value = Handler(eof),
State1 = [{Name, Value} | State],
fun (Next) -> parse_form_outer(Next, FileHandler, State1) end;
parse_form_file({body, Data}, {Name, Handler}, FileHandler, State) ->
H1 = Handler(Data),
fun (Next) -> parse_form_file(Next, {Name, H1}, FileHandler, State) end.
default_file_handler(Filename, ContentType) ->
default_file_handler_1(Filename, ContentType, []).
default_file_handler_1(Filename, ContentType, Acc) ->
fun(eof) ->
Value = iolist_to_binary(lists:reverse(Acc)),
{Filename, ContentType, Value};
(Next) ->
default_file_handler_1(Filename, ContentType, [Next | Acc])
end.
parse_multipart_request(Req, Callback) ->
%% TODO: Support chunked?
Length = list_to_integer(Req:get_header_value("content-length")),
Boundary = iolist_to_binary(
get_boundary(Req:get_header_value("content-type"))),
Prefix = <<"\r\n--", Boundary/binary>>,
BS = size(Boundary),
Chunk = read_chunk(Req, Length),
Length1 = Length - size(Chunk),
<<"--", Boundary:BS/binary, "\r\n", Rest/binary>> = Chunk,
feed_mp(headers, #mp{boundary=Prefix,
length=Length1,
buffer=Rest,
callback=Callback,
req=Req}).
parse_headers(<<>>) ->
[];
parse_headers(Binary) ->
parse_headers(Binary, []).
parse_headers(Binary, Acc) ->
case find_in_binary(<<"\r\n">>, Binary) of
{exact, N} ->
<<Line:N/binary, "\r\n", Rest/binary>> = Binary,
parse_headers(Rest, [split_header(Line) | Acc]);
not_found ->
lists:reverse([split_header(Binary) | Acc])
end.
split_header(Line) ->
{Name, [$: | Value]} = lists:splitwith(fun (C) -> C =/= $: end,
binary_to_list(Line)),
{string:to_lower(string:strip(Name)),
mochiweb_util:parse_header(Value)}.
read_chunk(Req, Length) when Length > 0 ->
case Length of
Length when Length < ?CHUNKSIZE ->
Req:recv(Length);
_ ->
Req:recv(?CHUNKSIZE)
end.
read_more(State=#mp{length=Length, buffer=Buffer, req=Req}) ->
Data = read_chunk(Req, Length),
Buffer1 = <<Buffer/binary, Data/binary>>,
State#mp{length=Length - size(Data),
buffer=Buffer1}.
feed_mp(headers, State=#mp{buffer=Buffer, callback=Callback}) ->
{State1, P} = case find_in_binary(<<"\r\n\r\n">>, Buffer) of
{exact, N} ->
{State, N};
_ ->
S1 = read_more(State),
%% Assume headers must be less than ?CHUNKSIZE
{exact, N} = find_in_binary(<<"\r\n\r\n">>,
S1#mp.buffer),
{S1, N}
end,
<<Headers:P/binary, "\r\n\r\n", Rest/binary>> = State1#mp.buffer,
NextCallback = Callback({headers, parse_headers(Headers)}),
feed_mp(body, State1#mp{buffer=Rest,
callback=NextCallback});
feed_mp(body, State=#mp{boundary=Prefix, buffer=Buffer, callback=Callback}) ->
case find_boundary(Prefix, Buffer) of
{end_boundary, Start, Skip} ->
<<Data:Start/binary, _:Skip/binary, Rest/binary>> = Buffer,
C1 = Callback({body, Data}),
C2 = C1(body_end),
{State#mp.length, Rest, C2(eof)};
{next_boundary, Start, Skip} ->
<<Data:Start/binary, _:Skip/binary, Rest/binary>> = Buffer,
C1 = Callback({body, Data}),
feed_mp(headers, State#mp{callback=C1(body_end),
buffer=Rest});
{maybe, Start} ->
<<Data:Start/binary, Rest/binary>> = Buffer,
feed_mp(body, read_more(State#mp{callback=Callback({body, Data}),
buffer=Rest}));
not_found ->
{Data, Rest} = {Buffer, <<>>},
feed_mp(body, read_more(State#mp{callback=Callback({body, Data}),
buffer=Rest}))
end.
get_boundary(ContentType) ->
{"multipart/form-data", Opts} = mochiweb_util:parse_header(ContentType),
case proplists:get_value("boundary", Opts) of
S when is_list(S) ->
S
end.
find_in_binary(B, Data) when size(B) > 0 ->
case size(Data) - size(B) of
Last when Last < 0 ->
partial_find(B, Data, 0, size(Data));
Last ->
find_in_binary(B, size(B), Data, 0, Last)
end.
find_in_binary(B, BS, D, N, Last) when N =< Last->
case D of
<<_:N/binary, B:BS/binary, _/binary>> ->
{exact, N};
_ ->
find_in_binary(B, BS, D, 1 + N, Last)
end;
find_in_binary(B, BS, D, N, Last) when N =:= 1 + Last ->
partial_find(B, D, N, BS - 1).
partial_find(_B, _D, _N, 0) ->
not_found;
partial_find(B, D, N, K) ->
<<B1:K/binary, _/binary>> = B,
case D of
<<_Skip:N/binary, B1:K/binary>> ->
{partial, N, K};
_ ->
partial_find(B, D, 1 + N, K - 1)
end.
find_boundary(Prefix, Data) ->
case find_in_binary(Prefix, Data) of
{exact, Skip} ->
PrefixSkip = Skip + size(Prefix),
case Data of
<<_:PrefixSkip/binary, "\r\n", _/binary>> ->
{next_boundary, Skip, size(Prefix) + 2};
<<_:PrefixSkip/binary, "--\r\n", _/binary>> ->
{end_boundary, Skip, size(Prefix) + 4};
_ when size(Data) < PrefixSkip + 4 ->
%% Underflow
{maybe, Skip};
_ ->
%% False positive
not_found
end;
{partial, Skip, Length} when (Skip + Length) =:= size(Data) ->
%% Underflow
{maybe, Skip};
_ ->
not_found
end.
with_socket_server(ServerFun, ClientFun) ->
{ok, Server} = mochiweb_socket_server:start([{ip, "127.0.0.1"},
{port, 0},
{loop, ServerFun}]),
Port = mochiweb_socket_server:get(Server, port),
{ok, Client} = gen_tcp:connect("127.0.0.1", Port,
[binary, {active, false}]),
Res = (catch ClientFun(Client)),
mochiweb_socket_server:stop(Server),
Res.
fake_request(Socket, ContentType, Length) ->
mochiweb_request:new(Socket,
'POST',
"/multipart",
{1,1},
mochiweb_headers:make(
[{"content-type", ContentType},
{"content-length", Length}])).
test_callback(Expect, [Expect | Rest]) ->
case Rest of
[] ->
ok;
_ ->
fun (Next) -> test_callback(Next, Rest) end
end.
test_parse3() ->
ContentType = "multipart/form-data; boundary=---------------------------7386909285754635891697677882",
BinContent = <<"-----------------------------7386909285754635891697677882\r\nContent-Disposition: form-data; name=\"hidden\"\r\n\r\nmultipart message\r\n-----------------------------7386909285754635891697677882\r\nContent-Disposition: form-data; name=\"file\"; filename=\"test_file.txt\"\r\nContent-Type: text/plain\r\n\r\nWoo multiline text file\n\nLa la la\r\n-----------------------------7386909285754635891697677882--\r\n">>,
Expect = [{headers,
[{"content-disposition",
{"form-data", [{"name", "hidden"}]}}]},
{body, <<"multipart message">>},
body_end,
{headers,
[{"content-disposition",
{"form-data", [{"name", "file"}, {"filename", "test_file.txt"}]}},
{"content-type", {"text/plain", []}}]},
{body, <<"Woo multiline text file\n\nLa la la">>},
body_end,
eof],
TestCallback = fun (Next) -> test_callback(Next, Expect) end,
ServerFun = fun (Socket) ->
case gen_tcp:send(Socket, BinContent) of
ok ->
exit(normal)
end
end,
ClientFun = fun (Socket) ->
Req = fake_request(Socket, ContentType,
size(BinContent)),
Res = parse_multipart_request(Req, TestCallback),
{0, <<>>, ok} = Res,
ok
end,
ok = with_socket_server(ServerFun, ClientFun),
ok.
test_parse2() ->
ContentType = "multipart/form-data; boundary=---------------------------6072231407570234361599764024",
BinContent = <<"-----------------------------6072231407570234361599764024\r\nContent-Disposition: form-data; name=\"hidden\"\r\n\r\nmultipart message\r\n-----------------------------6072231407570234361599764024\r\nContent-Disposition: form-data; name=\"file\"; filename=\"\"\r\nContent-Type: application/octet-stream\r\n\r\n\r\n-----------------------------6072231407570234361599764024--\r\n">>,
Expect = [{headers,
[{"content-disposition",
{"form-data", [{"name", "hidden"}]}}]},
{body, <<"multipart message">>},
body_end,
{headers,
[{"content-disposition",
{"form-data", [{"name", "file"}, {"filename", ""}]}},
{"content-type", {"application/octet-stream", []}}]},
{body, <<>>},
body_end,
eof],
TestCallback = fun (Next) -> test_callback(Next, Expect) end,
ServerFun = fun (Socket) ->
case gen_tcp:send(Socket, BinContent) of
ok ->
exit(normal)
end
end,
ClientFun = fun (Socket) ->
Req = fake_request(Socket, ContentType,
size(BinContent)),
Res = parse_multipart_request(Req, TestCallback),
{0, <<>>, ok} = Res,
ok
end,
ok = with_socket_server(ServerFun, ClientFun),
ok.
test_parse_form() ->
ContentType = "multipart/form-data; boundary=AaB03x",
"AaB03x" = get_boundary(ContentType),
Content = mochiweb_util:join(
["--AaB03x",
"Content-Disposition: form-data; name=\"submit-name\"",
"",
"Larry",
"--AaB03x",
"Content-Disposition: form-data; name=\"files\";"
++ "filename=\"file1.txt\"",
"Content-Type: text/plain",
"",
"... contents of file1.txt ...",
"--AaB03x--",
""], "\r\n"),
BinContent = iolist_to_binary(Content),
ServerFun = fun (Socket) ->
case gen_tcp:send(Socket, BinContent) of
ok ->
exit(normal)
end
end,
ClientFun = fun (Socket) ->
Req = fake_request(Socket, ContentType,
size(BinContent)),
Res = parse_form(Req),
[{"submit-name", "Larry"},
{"files", {"file1.txt", {"text/plain",[]},
<<"... contents of file1.txt ...">>}
}] = Res,
ok
end,
ok = with_socket_server(ServerFun, ClientFun),
ok.
test_parse() ->
ContentType = "multipart/form-data; boundary=AaB03x",
"AaB03x" = get_boundary(ContentType),
Content = mochiweb_util:join(
["--AaB03x",
"Content-Disposition: form-data; name=\"submit-name\"",
"",
"Larry",
"--AaB03x",
"Content-Disposition: form-data; name=\"files\";"
++ "filename=\"file1.txt\"",
"Content-Type: text/plain",
"",
"... contents of file1.txt ...",
"--AaB03x--",
""], "\r\n"),
BinContent = iolist_to_binary(Content),
Expect = [{headers,
[{"content-disposition",
{"form-data", [{"name", "submit-name"}]}}]},
{body, <<"Larry">>},
body_end,
{headers,
[{"content-disposition",
{"form-data", [{"name", "files"}, {"filename", "file1.txt"}]}},
{"content-type", {"text/plain", []}}]},
{body, <<"... contents of file1.txt ...">>},
body_end,
eof],
TestCallback = fun (Next) -> test_callback(Next, Expect) end,
ServerFun = fun (Socket) ->
case gen_tcp:send(Socket, BinContent) of
ok ->
exit(normal)
end
end,
ClientFun = fun (Socket) ->
Req = fake_request(Socket, ContentType,
size(BinContent)),
Res = parse_multipart_request(Req, TestCallback),
{0, <<>>, ok} = Res,
ok
end,
ok = with_socket_server(ServerFun, ClientFun),
ok.
test_find_boundary() ->
B = <<"\r\n--X">>,
{next_boundary, 0, 7} = find_boundary(B, <<"\r\n--X\r\nRest">>),
{next_boundary, 1, 7} = find_boundary(B, <<"!\r\n--X\r\nRest">>),
{end_boundary, 0, 9} = find_boundary(B, <<"\r\n--X--\r\nRest">>),
{end_boundary, 1, 9} = find_boundary(B, <<"!\r\n--X--\r\nRest">>),
not_found = find_boundary(B, <<"--X\r\nRest">>),
{maybe, 0} = find_boundary(B, <<"\r\n--X\r">>),
{maybe, 1} = find_boundary(B, <<"!\r\n--X\r">>),
P = <<"\r\n-----------------------------16037454351082272548568224146">>,
B0 = <<55,212,131,77,206,23,216,198,35,87,252,118,252,8,25,211,132,229,
182,42,29,188,62,175,247,243,4,4,0,59, 13,10,45,45,45,45,45,45,45,
45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,
49,54,48,51,55,52,53,52,51,53,49>>,
{maybe, 30} = find_boundary(P, B0),
ok.
test_find_in_binary() ->
{exact, 0} = find_in_binary(<<"foo">>, <<"foobarbaz">>),
{exact, 1} = find_in_binary(<<"oo">>, <<"foobarbaz">>),
{exact, 8} = find_in_binary(<<"z">>, <<"foobarbaz">>),
not_found = find_in_binary(<<"q">>, <<"foobarbaz">>),
{partial, 7, 2} = find_in_binary(<<"azul">>, <<"foobarbaz">>),
{exact, 0} = find_in_binary(<<"foobarbaz">>, <<"foobarbaz">>),
{partial, 0, 3} = find_in_binary(<<"foobar">>, <<"foo">>),
{partial, 1, 3} = find_in_binary(<<"foobar">>, <<"afoo">>),
ok.
test() ->
test_find_in_binary(),
test_find_boundary(),
test_parse(),
test_parse2(),
test_parse3(),
test_parse_form(),
ok.
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