Add multipart support

1 files changed, 249 insertions, 0 deletions

diff --git a/src/cowboy_multipart.erl b/src/cowboy_multipart.erl
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+++ b/src/cowboy_multipart.erl
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+%% Copyright (c) 2011, Anthony Ramine <[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 Multipart parser.
+-module(cowboy_multipart).
+
+-type part_parser() :: parser(more(part_result())).
+-type parser(T) :: fun((binary()) -> T).
+-type more(T) :: T | {more, parser(T)}.
+-type part_result() :: headers() | eof.
+-type headers() :: {headers, http_headers(), body_cont()}.
+-type http_headers() :: [{atom() | binary(), binary()}].
+-type body_cont() :: cont(more(body_result())).
+-type cont(T) :: fun(() -> T).
+-type body_result() :: {body, binary(), body_cont()} | end_of_part().
+-type end_of_part() :: {end_of_part, cont(more(part_result()))}.
+-type disposition() :: {binary(), [{binary(), binary()}]}.
+
+-export([parser/1, content_disposition/1]).
+
+-include_lib("eunit/include/eunit.hrl").
+
+%% API.
+
+%% @doc Return a multipart parser for the given boundary.
+-spec parser(binary()) -> part_parser().
+parser(Boundary) when is_binary(Boundary) ->
+	fun (Bin) when is_binary(Bin) -> parse(Bin, Boundary) end.
+
+%% @doc Parse a content disposition.
+%% @todo Parse the MIME header instead of the HTTP one.
+-spec content_disposition(binary()) -> disposition().
+content_disposition(Data) ->
+	cowboy_http:token_ci(Data,
+		fun (_Rest, <<>>) -> {error, badarg};
+			(Rest, Disposition) ->
+				cowboy_http:content_type_params(Rest,
+					fun (Params) -> {Disposition, Params} end, [])
+		end).
+
+%% Internal.
+
+%% @doc Entry point of the multipart parser, skips over the preamble if any.
+-spec parse(binary(), binary()) -> more(part_result()).
+parse(Bin, Boundary) when byte_size(Bin) >= byte_size(Boundary) + 2 ->
+	BoundarySize = byte_size(Boundary),
+	Pattern = pattern(Boundary),
+	case Bin of
+		<<"--", Boundary:BoundarySize/binary, Rest/binary>> ->
+			% Data starts with initial boundary, skip preamble parsing.
+			parse_boundary_tail(Rest, Pattern);
+		_ ->
+			% Parse preamble.
+			skip(Bin, Pattern)
+	end;
+parse(Bin, Boundary) ->
+	% Not enough data to know if the data begins with a boundary.
+	more(Bin, fun (NewBin) -> parse(NewBin, Boundary) end).
+
+-type pattern() :: {binary:cp(), non_neg_integer()}.
+
+%% @doc Return a compiled binary pattern with its size in bytes.
+%% The pattern is the boundary prepended with "\r\n--".
+-spec pattern(binary()) -> pattern().
+pattern(Boundary) ->
+	MatchPattern = <<"\r\n--", Boundary/binary>>,
+	{binary:compile_pattern(MatchPattern), byte_size(MatchPattern)}.
+
+%% @doc Parse remaining characters of a line beginning with the boundary.
+%% If followed by "--", <em>eof</em> is returned and parsing is finished.
+-spec parse_boundary_tail(binary(), pattern()) -> more(part_result()).
+parse_boundary_tail(Bin, Pattern) when byte_size(Bin) >= 2 ->
+	case Bin of
+		<<"--", _Rest/binary>> ->
+			% Boundary is followed by "--", end parsing.
+			eof;
+		_ ->
+			% No dash after boundary, proceed with unknown chars and lwsp
+			% removal.
+			parse_boundary_eol(Bin, Pattern)
+	end;
+parse_boundary_tail(Bin, Pattern) ->
+	% Boundary may be followed by "--", need more data.
+	more(Bin, fun (NewBin) -> parse_boundary_tail(NewBin, Pattern) end).
+
+%% @doc Skip whitespace and unknown chars until CRLF.
+-spec parse_boundary_eol(binary(), pattern()) -> more(part_result()).
+parse_boundary_eol(Bin, Pattern) ->
+	case binary:match(Bin, <<"\r\n">>) of
+		{CrlfStart, _Length} ->
+			% End of line found, remove optional whitespace.
+			<<_:CrlfStart/binary, Rest/binary>> = Bin,
+			Fun = fun (Rest2) -> parse_boundary_crlf(Rest2, Pattern) end,
+			cowboy_http:whitespace(Rest, Fun);
+		nomatch ->
+			% CRLF not found in the given binary.
+			RestStart = max(byte_size(Bin) - 1, 0),
+			<<_:RestStart/binary, Rest/binary>> = Bin,
+			more(Rest, fun (NewBin) -> parse_boundary_eol(NewBin, Pattern) end)
+	end.
+
+-spec parse_boundary_crlf(binary(), pattern()) -> more(part_result()).
+parse_boundary_crlf(<<"\r\n", Rest/binary>>, Pattern) ->
+	% The binary is at least 2 bytes long as this function is only called by
+	% parse_boundary_eol/3 when CRLF has been found so a more tuple will never
+	% be returned from here.
+	parse_headers(Rest, Pattern);
+parse_boundary_crlf(Bin, Pattern) ->
+	% Unspecified behaviour here: RFC 2046 doesn't say what to do when LWSP is
+	% not followed directly by a new line. In this implementation it is
+	% considered part of the boundary so EOL needs to be searched again.
+	parse_boundary_eol(Bin, Pattern).
+
+-spec parse_headers(binary(), pattern()) -> more(part_result()).
+parse_headers(Bin, Pattern) ->
+  parse_headers(Bin, Pattern, []).
+
+-spec parse_headers(binary(), pattern(), http_headers()) -> more(part_result()).
+parse_headers(Bin, Pattern, Acc) ->
+	case erlang:decode_packet(httph_bin, Bin, []) of
+		{ok, {http_header, _, Name, _, Value}, Rest} ->
+			parse_headers(Rest, Pattern, [{Name, Value} | Acc]);
+		{ok, http_eoh, Rest} ->
+			Headers = lists:reverse(Acc),
+			{headers, Headers, fun () -> parse_body(Rest, Pattern) end};
+		{ok, {http_error, _}, _} ->
+			% Skip malformed parts.
+			skip(Bin, Pattern);
+		{more, _} ->
+			more(Bin, fun (NewBin) -> parse_headers(NewBin, Pattern, Acc) end)
+	end.
+
+-spec parse_body(binary(), pattern()) -> more(body_result()).
+parse_body(Bin, Pattern = {P, PSize}) when byte_size(Bin) >= PSize ->
+	case binary:match(Bin, P) of
+		{0, _Length} ->
+			<<_:PSize/binary, Rest/binary>> = Bin,
+			end_of_part(Rest, Pattern);
+		{BoundaryStart, _Length} ->
+			% Boundary found, this is the latest partial body that will be
+			% returned for this part.
+			<<PBody:BoundaryStart/binary, _:PSize/binary, Rest/binary>> = Bin,
+			FResult = end_of_part(Rest, Pattern),
+			{body, PBody, fun () -> FResult end};
+		nomatch ->
+			PartialLength = byte_size(Bin) - PSize + 1,
+			<<PBody:PartialLength/binary, Rest/binary>> = Bin,
+			{body, PBody, fun () -> parse_body(Rest, Pattern) end}
+	end;
+parse_body(Bin, Pattern) ->
+	more(Bin, fun (NewBin) -> parse_body(NewBin, Pattern) end).
+
+-spec end_of_part(binary(), pattern()) -> end_of_part().
+end_of_part(Bin, Pattern) ->
+	{end_of_part, fun () -> parse_boundary_tail(Bin, Pattern) end}.
+
+-spec skip(binary(), pattern()) -> more(part_result()).
+skip(Bin, Pattern = {P, PSize}) ->
+	case binary:match(Bin, P) of
+		{BoundaryStart, _Length} ->
+			% Boundary found, proceed with parsing of the next part.
+			RestStart = BoundaryStart + PSize,
+			<<_:RestStart/binary, Rest/binary>> = Bin,
+			parse_boundary_tail(Rest, Pattern);
+		nomatch ->
+			% Boundary not found, need more data.
+			RestStart = max(byte_size(Bin) - PSize + 1, 0),
+			<<_:RestStart/binary, Rest/binary>> = Bin,
+			more(Rest, fun (NewBin) -> skip(NewBin, Pattern) end)
+	end.
+
+-spec more(binary(), parser(T)) -> {more, parser(T)}.
+more(<<>>, F) ->
+	{more, F};
+more(Bin, InnerF) ->
+	F = fun (NewData) when is_binary(NewData) ->
+				InnerF(<<Bin/binary, NewData/binary>>)
+		end,
+	{more, F}.
+
+%% Tests.
+
+-ifdef(TEST).
+
+multipart_test_() ->
+	%% {Body, Result}
+	Tests = [
+		{<<"--boundary--">>, []},
+		{<<"preamble\r\n--boundary--">>, []},
+		{<<"--boundary--\r\nepilogue">>, []},
+		{<<"\r\n--boundary\r\nA:b\r\nC:d\r\n\r\n\r\n--boundary--">>,
+			[{[{<<"A">>, <<"b">>}, {<<"C">>, <<"d">>}], <<>>}]},
+		{
+			<<
+				"--boundary\r\nX-Name:answer\r\n\r\n42"
+				"\r\n--boundary\r\nServer:Cowboy\r\n\r\nIt rocks!\r\n"
+				"\r\n--boundary--"
+			>>,
+			[
+				{[{<<"X-Name">>, <<"answer">>}], <<"42">>},
+				{[{'Server', <<"Cowboy">>}], <<"It rocks!\r\n">>}
+			]
+		}
+	],
+	[{title(V), fun () -> R = acc_multipart(V) end} || {V, R} <- Tests].
+
+acc_multipart(V) ->
+	acc_multipart((parser(<<"boundary">>))(V), []).
+
+acc_multipart({headers, Headers, Cont}, Acc) ->
+	acc_multipart(Cont(), [{Headers, []}|Acc]);
+acc_multipart({body, Body, Cont}, [{Headers, BodyAcc}|Acc]) ->
+	acc_multipart(Cont(), [{Headers, [Body|BodyAcc]}|Acc]);
+acc_multipart({end_of_part, Cont}, [{Headers, BodyAcc}|Acc]) ->
+	Body = list_to_binary(lists:reverse(BodyAcc)),
+	acc_multipart(Cont(), [{Headers, Body}|Acc]);
+acc_multipart(eof, Acc) ->
+	lists:reverse(Acc).
+
+content_disposition_test_() ->
+	%% {Disposition, Result}
+	Tests = [
+		{<<"form-data; name=id">>, {<<"form-data">>, [{<<"name">>, <<"id">>}]}},
+		{<<"inline">>, {<<"inline">>, []}},
+		{<<"attachment; \tfilename=brackets-slides.pdf">>,
+			{<<"attachment">>, [{<<"filename">>, <<"brackets-slides.pdf">>}]}}
+	],
+	[{title(V), fun () -> R = content_disposition(V) end} || {V, R} <- Tests].
+
+title(Bin) ->
+	Title = lists:foldl(
+		fun ({T, R}, V) -> re:replace(V, T, R, [global]) end,
+		Bin,
+		[{"\t", "\\\\t"}, {"\r", "\\\\r"}, {"\n", "\\\\n"}]
+	),
+	iolist_to_binary(Title).
+
+-endif.