%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2004-2011. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%% Description: Implements chunked transfer encoding see RFC2616 section
%% 3.6.1
-module(http_chunk).
-include("http_internal.hrl").
%% API
-export([decode/3, decode/4, encode/1, encode_last/0, handle_headers/2]).
%% Callback API - used for example if the chunkedbody is received a
%% little at a time on a socket.
-export([decode_size/1, ignore_extensions/1, decode_data/1, decode_trailer/1]).
%%%=========================================================================
%%% API
%%%=========================================================================
%%-------------------------------------------------------------------------
%% decode(ChunkedBody, MaxBodySize, MaxHeaderSize, <Stream>) ->
%% {ok, {Headers, Body}} | {Module, Function, Args}
%%
%% Headers = ["Header:Value"]
%% ChunkedBody = binary()
%% MaxBodySize = integer()
%% MaxHeaderSize = integer()
%% Stream = {Code, Request} - if Request#request.stream =/= none
%% and Code == 200 the side effect of sending each decode chunk to the
%% client/file before the whole body is received will take place.
%%
%% Note: decode/4 should only be used from httpc_handler module.
%% Otherwhise use the side effect free decode/3.
%%
%% Description: Decodes a body encoded by the chunked transfer
%% encoding. If the ChunkedBody is not compleate it returns {Module,
%% Function, Args} so that decoding can be continued when more of the
%% data has been received by calling Module:Function([NewData | Args]).
%%
%% Note: In the case of pipelining a call to decode might contain data
%% that belongs to the next request/response and will be returned as
%% part of the body, hence functions calling http_chunk:decode must
%% look at the returned content-length header to make sure that they
%% split the actual body and data that possible should be passed along to
%% the next pass in the loop.
%%-------------------------------------------------------------------------
decode(ChunkedBody, MaxBodySize, MaxHeaderSize) ->
decode(ChunkedBody, MaxBodySize, MaxHeaderSize, false).
decode(ChunkedBody, MaxBodySize, MaxHeaderSize, Stream) ->
%% Note decode_size will call decode_data.
decode_size([ChunkedBody, <<>>, [],
{MaxBodySize, <<>>, 0, MaxHeaderSize, Stream}]).
%%-------------------------------------------------------------------------
%% encode(Chunk) -> EncodedChunk
%%
%% Chunked = binary()
%% EncodedChunk = binary()
%%
%% Description: Encodes a body part with the chunked transfer encoding.
%% Chunks are returned as lists or binaries depending on the
%% input format. When sending the data on the both formats
%% are accepted.
%%-------------------------------------------------------------------------
encode(Chunk) when is_binary(Chunk)->
HEXSize = list_to_binary(http_util:integer_to_hexlist(size(Chunk))),
<<HEXSize/binary, ?CR, ?LF, Chunk/binary, ?CR, ?LF>>;
encode([<<>>]) ->
[];
encode(Chunk) when is_list(Chunk)->
HEXSize = http_util:integer_to_hexlist(erlang:iolist_size(Chunk)),
[HEXSize, ?CR, ?LF, Chunk, ?CR, ?LF].
encode_last() ->
<<$0, ?CR, ?LF, ?CR, ?LF >>.
%%-------------------------------------------------------------------------
%% handle_headers(HeaderRecord, ChunkedHeaders) -> NewHeaderRecord
%%
%% HeaderRecord = NewHeaderRecord = #http_request_h{} | #http_response_h{}
%% ChunkedHeaders = ["Header:Value"] as returnde by http_chunk:decode/3
%%
%% Description: Removes chunked from the header as we now have decode
%% the body and adds a content-length header and any other headers
%% found in the chunked trail.
%%-------------------------------------------------------------------------
handle_headers(RequestHeaderRecord = #http_request_h{}, ChunkedHeaders) ->
NewHeaders = http_request:headers(ChunkedHeaders, RequestHeaderRecord),
TransferEncoding =
case NewHeaders#http_request_h.'transfer-encoding' -- "chunked" of
"" ->
undefined;
Other ->
Other
end,
NewHeaders#http_request_h{'transfer-encoding' = TransferEncoding};
handle_headers(ResponseHeaderRecord = #http_response_h{}, ChunkedHeaders) ->
NewHeaders = http_response:headers(ChunkedHeaders, ResponseHeaderRecord),
TransferEncoding =
case NewHeaders#http_response_h.'transfer-encoding' -- "chunked" of
"" ->
undefined;
Other ->
Other
end,
NewHeaders#http_response_h{'transfer-encoding' = TransferEncoding}.
%% Functions that may be returned during the decoding process
%% if the input data is incompleate.
decode_size([Bin, Rest, HexList, Info]) ->
decode_size(<<Rest/binary, Bin/binary>>, HexList, Info).
ignore_extensions([Bin, Rest, NextFunction]) ->
ignore_extensions(<<Rest/binary, Bin/binary>>, NextFunction).
decode_data([Bin, ChunkSize, TotalChunk, Info]) ->
decode_data(ChunkSize, <<TotalChunk/binary, Bin/binary>>, Info).
decode_trailer([Bin, Rest, Header, Headers, MaxHeaderSize, Body,
BodyLength]) ->
decode_trailer(<<Rest/binary, Bin/binary>>,
Header, Headers, MaxHeaderSize, Body, BodyLength).
%%%========================================================================
%%% Internal functions
%%%========================================================================
decode_size(<<>>, HexList, Info) ->
{?MODULE, decode_size, [<<>>, HexList, Info]};
decode_size(Data = <<?CR, ?LF, ChunkRest/binary>>, HexList,
{MaxBodySize, Body,
AccLength,
MaxHeaderSize, Stream}) ->
ChunkSize = http_util:hexlist_to_integer(lists:reverse(HexList)),
case ChunkSize of
0 -> % Last chunk, there was no data
ignore_extensions(Data, {?MODULE, decode_trailer,
[<<>>, [],[], MaxHeaderSize,
Body,
integer_to_list(AccLength)]});
_ ->
%% Note decode_data may call decode_size again if there
%% is more than one chunk, hence here is where the last parameter
%% to this function comes in.
decode_data(ChunkSize, ChunkRest, {MaxBodySize, Body,
ChunkSize + AccLength ,
MaxHeaderSize, Stream})
end;
decode_size(<<";", Rest/binary>>, HexList, Info) ->
%% Note ignore_extensions will call decode_size/1 again when
%% it ignored all extensions.
ignore_extensions(Rest, {?MODULE, decode_size, [<<>>, HexList, Info]});
decode_size(<<?CR>> = Data, HexList, Info) ->
{?MODULE, decode_size, [Data, HexList, Info]};
decode_size(<<Octet, Rest/binary>>, HexList, Info) ->
decode_size(Rest, [Octet | HexList], Info).
%% "All applications MUST ignore chunk-extension extensions they
%% do not understand.", see RFC 2616 Section 3.6.1 We don't
%% understand any extension...
ignore_extensions(<<>>, NextFunction) ->
{?MODULE, ignore_extensions, [<<>>, NextFunction]};
ignore_extensions(Data = <<?CR, ?LF, _ChunkRest/binary>>,
{Module, Function, Args}) ->
Module:Function([Data | Args]);
ignore_extensions(<<?CR>> = Data, NextFunction) ->
{?MODULE, ignore_extensions, [Data, NextFunction]};
ignore_extensions(<<_Octet, Rest/binary>>, NextFunction) ->
ignore_extensions(Rest, NextFunction).
decode_data(ChunkSize, TotalChunk,
Info = {MaxBodySize, BodySoFar, AccLength, MaxHeaderSize, Stream})
when ChunkSize =< size(TotalChunk) ->
case TotalChunk of
%% Last chunk
<<Data:ChunkSize/binary, ?CR, ?LF, "0", ";">> ->
%% Note ignore_extensions will call decode_trailer/1
%% once it ignored all extensions.
{NewBody, _} =
stream(<<BodySoFar/binary, Data/binary>>, Stream),
{?MODULE, ignore_extensions,
[<<>>,
{?MODULE, decode_trailer, [<<>>, [],[], MaxHeaderSize,
NewBody,
integer_to_list(AccLength)]}]};
<<Data:ChunkSize/binary, ?CR, ?LF, "0", ";", Rest/binary>> ->
%% Note ignore_extensions will call decode_trailer/1
%% once it ignored all extensions.
{NewBody, _} = stream(<<BodySoFar/binary, Data/binary>>, Stream),
ignore_extensions(Rest, {?MODULE, decode_trailer,
[<<>>, [],[], MaxHeaderSize,
NewBody,
integer_to_list(AccLength)]});
<<Data:ChunkSize/binary, ?CR, ?LF, "0", ?CR, ?LF>> ->
{NewBody, _} = stream(<<BodySoFar/binary, Data/binary>>, Stream),
{?MODULE, decode_trailer, [<<?CR, ?LF>>, [],[], MaxHeaderSize,
NewBody,
integer_to_list(AccLength)]};
<<Data:ChunkSize/binary, ?CR, ?LF, "0", ?CR, ?LF, Rest/binary>> ->
{NewBody,_}= stream(<<BodySoFar/binary, Data/binary>>, Stream),
decode_trailer(<<?CR, ?LF, Rest/binary>>, [],[], MaxHeaderSize,
NewBody,
integer_to_list(AccLength));
%% There are more chunks, so here we go agin...
<<Data:ChunkSize/binary, ?CR, ?LF>> ->
{NewBody, NewStream} =
stream(<<BodySoFar/binary, Data/binary>>, Stream),
{?MODULE, decode_size, [<<>>, [], {MaxBodySize, NewBody, AccLength, MaxHeaderSize, NewStream}]};
<<Data:ChunkSize/binary, ?CR, ?LF, Rest/binary>>
when (AccLength < MaxBodySize) or (MaxBodySize == nolimit) ->
{NewBody, NewStream} =
stream(<<BodySoFar/binary, Data/binary>>, Stream),
decode_size(Rest, [],
{MaxBodySize, NewBody,
AccLength, MaxHeaderSize, NewStream});
<<_:ChunkSize/binary, ?CR, ?LF, _/binary>> ->
throw({error, body_too_big});
_ ->
{?MODULE, decode_data, [ChunkSize, TotalChunk, Info]}
end;
decode_data(ChunkSize, TotalChunk, Info) ->
{?MODULE, decode_data, [ChunkSize, TotalChunk, Info]}.
decode_trailer(<<>>, Header, Headers, MaxHeaderSize, Body, BodyLength) ->
{?MODULE, decode_trailer, [<<>>, Header, Headers, MaxHeaderSize, Body,
BodyLength]};
%% Note: If Bin is not empty it is part of a pipelined request/response.
decode_trailer(<<?CR,?LF,?CR,?LF, Bin/binary>>, [], [], _, Body, BodyLength) ->
{ok, {["content-length:" ++ BodyLength], <<Body/binary, Bin/binary>>}};
decode_trailer(<<?CR,?LF,?CR,?LF, Bin/binary>>,
Header, Headers, MaxHeaderSize, Body, BodyLength) ->
NewHeaders = case Header of
[] ->
Headers;
_ ->
[lists:reverse(Header) | Headers]
end,
Length = length(NewHeaders),
case Length > MaxHeaderSize of
true ->
throw({error, {header_too_long, MaxHeaderSize,
MaxHeaderSize-Length}});
false ->
{ok, {["content-length:" ++ BodyLength | NewHeaders],
<<Body/binary, Bin/binary>>}}
end;
decode_trailer(<<?CR,?LF,?CR>> = Data, Header, Headers, MaxHeaderSize,
Body, BodyLength) ->
{?MODULE, decode_trailer, [Data, Header, Headers, MaxHeaderSize, Body,
BodyLength]};
decode_trailer(<<?CR,?LF>> = Data, Header, Headers, MaxHeaderSize,
Body, BodyLength) ->
{?MODULE, decode_trailer, [Data, Header, Headers, MaxHeaderSize, Body,
BodyLength]};
decode_trailer(<<?CR>> = Data, Header, Headers, MaxHeaderSize,
Body, BodyLength) ->
{?MODULE, decode_trailer, [Data, Header, Headers, MaxHeaderSize, Body,
BodyLength]};
decode_trailer(<<?CR, ?LF, Rest/binary>>, Header, Headers,
MaxHeaderSize, Body, BodyLength) ->
decode_trailer(Rest, [], [lists:reverse(Header) | Headers],
MaxHeaderSize, Body, BodyLength);
decode_trailer(<<Octet, Rest/binary>>, Header, Headers, MaxHeaderSize, Body,
BodyLength) ->
decode_trailer(Rest, [Octet | Header], Headers, MaxHeaderSize,
Body, BodyLength).
stream(BodyPart, false) ->
{BodyPart, false};
stream(BodyPart, {Code, Request}) ->
{NewBody, NewRequest} = httpc_handler:stream(BodyPart, Request, Code),
{NewBody, {Code, NewRequest}}.
