Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 11fad66ab7
Fetching contributors…

Cannot retrieve contributors at this time

file 644 lines (603 sloc) 26.284 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644
%%% ----------------------------------------------------------------------------
%%% Copyright (c) 2009, Erlang Training and Consulting Ltd.
%%% All rights reserved.
%%%
%%% Redistribution and use in source and binary forms, with or without
%%% modification, are permitted provided that the following conditions are met:
%%% * Redistributions of source code must retain the above copyright
%%% notice, this list of conditions and the following disclaimer.
%%% * Redistributions in binary form must reproduce the above copyright
%%% notice, this list of conditions and the following disclaimer in the
%%% documentation and/or other materials provided with the distribution.
%%% * Neither the name of Erlang Training and Consulting Ltd. nor the
%%% names of its contributors may be used to endorse or promote products
%%% derived from this software without specific prior written permission.
%%%
%%% THIS SOFTWARE IS PROVIDED BY Erlang Training and Consulting Ltd. ''AS IS''
%%% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
%%% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
%%% ARE DISCLAIMED. IN NO EVENT SHALL Erlang Training and Consulting Ltd. BE
%%% LIABLE SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
%%% BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
%%% WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
%%% OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
%%% ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
%%% ----------------------------------------------------------------------------

%%% @private
%%% @author Oscar Hellström <oscar@hellstrom.st>
%%% @doc
%%% This module implements the HTTP request handling. This should normally
%%% not be called directly since it should be spawned by the lhttpc module.
%%% @end
-module(lhttpc_client).

-export([request/10, request_with_timeout/2]).

-include("lhttpc_types.hrl").

-record(client_state, {
        req_id :: tuple(),
        host :: string(),
        port = 80 :: integer(),
        ssl = false :: true | false,
        method :: string(),
        request :: iolist(),
        request_headers :: headers(),
        load_balancer:: pid(),
        socket,
        connect_timeout = infinity :: timeout(),
        connect_options = [] :: [any()],
        attempts :: integer(),
        requester :: pid(),
        partial_upload = false :: true | false,
        chunked_upload = false :: true | false,
        upload_window :: non_neg_integer() | infinity,
        partial_download = false :: true | false,
        download_window = infinity :: timeout(),
        part_size :: non_neg_integer() | infinity
        %% in case of infinity we read whatever data we can get from
        %% the wire at that point or in case of chunked one chunk
    }).

-define(CONNECTION_HDR(HDRS, DEFAULT),
    string:to_lower(lhttpc_lib:header_value("connection", HDRS, DEFAULT))).

request_with_timeout(Timeout, [ReqId, StreamTo, _Host, _Port, _Ssl, _Path, _Method, _Hdrs, _Body, _Options] = Args) ->
    TimerRef = erlang:send_after(Timeout, lhttpc_manager, {kill_client_after_timeout, ReqId, self(), StreamTo}),
    ok = apply(?MODULE, request, Args),
    erlang:cancel_timer(TimerRef).

-spec request(tuple(), pid(), string(), 1..65535, true | false, string(),
        string() | atom(), headers(), iolist(), [option()]) -> no_return().
%% @spec (ReqId, From, Host, Port, Ssl, Path, Method, Hdrs, RequestBody, Options) -> ok
%% ReqId = tuple()
%% From = pid()
%% Host = string()
%% Port = integer()
%% Ssl = boolean()
%% Method = atom() | string()
%% Hdrs = [Header]
%% Header = {string() | atom(), string()}
%% Body = iolist()
%% Options = [Option]
%% Option = {connect_timeout, Milliseconds}
%% @end
request(ReqId, From, Host, Port, Ssl, Path, Method, Hdrs, Body, Options) ->
    Result = try
        execute(ReqId, From, Host, Port, Ssl, Path, Method, Hdrs, Body, Options)
    catch
        Reason ->
            {response, ReqId, self(), {error, Reason}};
        error:closed ->
            {response, ReqId, self(), {error, connection_closed}};
        error:Error ->
            {exit, ReqId, self(), {Error, erlang:get_stacktrace()}}
    end,
    case Result of
        {response, _, _, {ok, {no_return, _}}} -> ok;
        _Else -> From ! Result
    end,
    % Don't send back {'EXIT', self(), normal} if the process
    % calling us is trapping exits
    unlink(From),
    ok.

execute(ReqId, From, Host, Port, Ssl, Path, Method, Hdrs, Body, Options) ->
    UploadWindowSize = proplists:get_value(partial_upload, Options),
    PartialUpload = proplists:is_defined(partial_upload, Options),
    PartialDownload = proplists:is_defined(partial_download, Options),
    PartialDownloadOptions = proplists:get_value(partial_download, Options, []),
    ConnectOptions = proplists:get_value(connect_options, Options, []),
    NormalizedMethod = lhttpc_lib:normalize_method(Method),
    MaxConnections = proplists:get_value(max_connections, Options, 10),
    ConnectionTimeout = proplists:get_value(connection_timeout, Options, infinity),
    {ChunkedUpload, Request} = lhttpc_lib:format_request(Path, NormalizedMethod,
        Hdrs, Host, Port, Body, PartialUpload),
    LbRequest = {lb, Host, Port, Ssl, MaxConnections, ConnectionTimeout},
    {ok, Lb} = gen_server:call(lhttpc_manager, LbRequest, infinity),
    State = #client_state{
        req_id = ReqId,
        host = Host,
        port = Port,
        ssl = Ssl,
        method = NormalizedMethod,
        request = Request,
        requester = From,
        request_headers = Hdrs,
        load_balancer = Lb,
        connect_timeout = proplists:get_value(connect_timeout, Options,
            infinity),
        connect_options = ConnectOptions,
        attempts = 1 + proplists:get_value(send_retry, Options, 1),
        partial_upload = PartialUpload,
        upload_window = UploadWindowSize,
        chunked_upload = ChunkedUpload,
        partial_download = PartialDownload,
        download_window = proplists:get_value(window_size,
            PartialDownloadOptions, infinity),
        part_size = proplists:get_value(part_size,
            PartialDownloadOptions, infinity)
    },
    Response = case send_request(State) of
        {R, undefined} ->
            {ok, R};
        {R, NewSocket} ->
            case lhttpc_sock:controlling_process(NewSocket, Lb, Ssl) of
                ok ->
                    gen_server:cast(Lb, {store, NewSocket});
                _ ->
                    ok
            end,
            {ok, R}
    end,
    {response, ReqId, self(), Response}.

send_request(#client_state{attempts = 0}) ->
    throw(connection_closed);
send_request(#client_state{socket = undefined} = State) ->
    ConnectOptions = State#client_state.connect_options,
    ConnectTimeout = State#client_state.connect_timeout,
    Lb = State#client_state.load_balancer,
    SocketRequest = {socket, self(), ConnectOptions, ConnectTimeout},
    case gen_server:call(Lb, SocketRequest, infinity) of
        {ok, Socket} ->
            lhttpc_sock:setopts(Socket, [{active, false}], State#client_state.ssl),
            send_request(State#client_state{socket = Socket});
        {error, Reason} ->
            throw(Reason)
    end;
send_request(State) ->
    Lb = State#client_state.load_balancer,
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    Request = State#client_state.request,
    case lhttpc_sock:send(Socket, Request, Ssl) of
        ok ->
            if
                State#client_state.partial_upload -> partial_upload(State);
                not State#client_state.partial_upload -> read_response(State)
            end;
        {error, closed} ->
            gen_server:cast(Lb, {remove, Socket}),
            NewState = State#client_state{
                socket = undefined,
                attempts = State#client_state.attempts - 1
            },
            send_request(NewState);
        {error, Reason} ->
            gen_server:cast(Lb, {remove, Socket}),
            erlang:error(Reason)
    end.

partial_upload(State) ->
    Response = {ok, {self(), State#client_state.upload_window}},
    State#client_state.requester ! {response, State#client_state.req_id, self(), Response},
    partial_upload_loop(State#client_state{attempts = 1, request = undefined}).

partial_upload_loop(State = #client_state{requester = Pid}) ->
    receive
        {trailers, Pid, Trailers} ->
            send_trailers(State, Trailers),
            read_response(State);
        {body_part, Pid, http_eob} ->
            send_body_part(State, http_eob),
            read_response(State);
        {body_part, Pid, Data} ->
            send_body_part(State, Data),
            Pid ! {ack, self()},
            partial_upload_loop(State)
    end.

send_body_part(State = #client_state{socket = Socket, ssl = Ssl}, BodyPart) ->
    Data = encode_body_part(State, BodyPart),
    check_send_result(State, lhttpc_sock:send(Socket, Data, Ssl)).

send_trailers(State = #client_state{chunked_upload = true}, Trailers) ->
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    Data = [<<"0\r\n">>, lhttpc_lib:format_hdrs(Trailers)],
    check_send_result(State, lhttpc_sock:send(Socket, Data, Ssl));
send_trailers(#client_state{chunked_upload = false}, _Trailers) ->
    erlang:error(trailers_not_allowed).

encode_body_part(#client_state{chunked_upload = true}, http_eob) ->
    <<"0\r\n\r\n">>; % We don't send trailers after http_eob
encode_body_part(#client_state{chunked_upload = false}, http_eob) ->
    <<>>;
encode_body_part(#client_state{chunked_upload = true}, Data) ->
    Size = list_to_binary(erlang:integer_to_list(iolist_size(Data), 16)),
    [Size, <<"\r\n">>, Data, <<"\r\n">>];
encode_body_part(#client_state{chunked_upload = false}, Data) ->
    Data.

check_send_result(_State, ok) ->
    ok;
check_send_result(#client_state{socket = Socket, load_balancer = Lb}, {error, Reason}) ->
    gen_server:cast(Lb, {remove, Socket}),
    throw(Reason).

read_response(#client_state{socket = Socket, ssl = Ssl} = State) ->
    lhttpc_sock:setopts(Socket, [{packet, http}], Ssl),
    read_response(State, nil, {nil, nil}, []).

read_response(State, Vsn, {StatusCode, _} = Status, Hdrs) ->
    Lb = State#client_state.load_balancer,
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    case lhttpc_sock:recv(Socket, Ssl) of
        {ok, {http_response, NewVsn, NewStatusCode, Reason}} ->
            NewStatus = {NewStatusCode, Reason},
            read_response(State, NewVsn, NewStatus, Hdrs);
        {ok, {http_header, _, Name, _, Value}} ->
            Header = {lhttpc_lib:maybe_atom_to_list(Name), Value},
            read_response(State, Vsn, Status, [Header | Hdrs]);
        {ok, http_eoh} when StatusCode >= 100, StatusCode =< 199 ->
            % RFC 2616, section 10.1:
            % A client MUST be prepared to accept one or more
            % 1xx status responses prior to a regular
            % response, even if the client does not expect a
            % 100 (Continue) status message. Unexpected 1xx
            % status responses MAY be ignored by a user agent.
            read_response(State, nil, {nil, nil}, []);
        {ok, http_eoh} ->
            lhttpc_sock:setopts(Socket, [{packet, raw}], Ssl),
            Response = handle_response_body(State, Vsn, Status, Hdrs),
            NewHdrs = element(2, Response),
            ReqHdrs = State#client_state.request_headers,
            NewSocket = maybe_close_socket(Lb, Socket, Vsn, ReqHdrs, NewHdrs),
            {Response, NewSocket};
        {error, closed} ->
            % Either we only noticed that the socket was closed after we
            % sent the request, the server closed it just after we put
            % the request on the wire or the server has some issues and is
            % closing connections without sending responses.
            % If this the first attempt to send the request, we will try again.
            gen_server:cast(Lb, {remove, Socket}),
            NewState = State#client_state{
                socket = undefined,
                attempts = State#client_state.attempts - 1
            },
            send_request(NewState);
        {error, timeout} ->
            gen_server:cast(Lb, {remove, Socket}),
            NewState = State#client_state{
                socket = undefined,
                attempts = 0
            },
            send_request(NewState)
    end.

handle_response_body(#client_state{partial_download = false} = State, Vsn,
        Status, Hdrs) ->
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    Method = State#client_state.method,
    {Body, NewHdrs} = case has_body(Method, element(1, Status), Hdrs) of
        true -> read_body(Vsn, Hdrs, Ssl, Socket, body_type(Hdrs));
        false -> {<<>>, Hdrs}
    end,
    {Status, NewHdrs, Body};
handle_response_body(#client_state{partial_download = true} = State, Vsn,
        Status, Hdrs) ->
    Method = State#client_state.method,
    case has_body(Method, element(1, Status), Hdrs) of
        true ->
            Response = {ok, {Status, Hdrs, self()}},
            State#client_state.requester ! {response, State#client_state.req_id, self(), Response},
            MonRef = erlang:monitor(process, State#client_state.requester),
            Res = read_partial_body(State, Vsn, Hdrs, body_type(Hdrs)),
            erlang:demonitor(MonRef, [flush]),
            Res;
        false ->
            {Status, Hdrs, undefined}
    end.

has_body("HEAD", _, _) ->
    % HEAD responses aren't allowed to include a body
    false;
has_body("OPTIONS", _, Hdrs) ->
    % OPTIONS can include a body, if Content-Length or Transfer-Encoding
    % indicates it
    ContentLength = lhttpc_lib:header_value("content-length", Hdrs),
    TransferEncoding = lhttpc_lib:header_value("transfer-encoding", Hdrs),
    case {ContentLength, TransferEncoding} of
        {undefined, undefined} -> false;
        {_, _} -> true
    end;
has_body(_, 204, _) ->
    false; % RFC 2616 10.2.5: 204 No Content
has_body(_, 304, _) ->
    false; % RFC 2616 10.3.5: 304 Not Modified
has_body(_, _, _) ->
    true. % All other responses are assumed to have a body

body_type(Hdrs) ->
    % Find out how to read the entity body from the request.
    % * If we have a Content-Length, just use that and read the complete
    % entity.
    % * If Transfer-Encoding is set to chunked, we should read one chunk at
    % the time
    % * If neither of this is true, we need to read until the socket is
    % closed (AFAIK, this was common in versions before 1.1).
    case lhttpc_lib:header_value("content-length", Hdrs) of
        undefined ->
            TransferEncoding = string:to_lower(
                lhttpc_lib:header_value("transfer-encoding", Hdrs, "undefined")
            ),
            case TransferEncoding of
                "chunked" -> chunked;
                _ -> infinite
            end;
        ContentLength ->
            {fixed_length, list_to_integer(ContentLength)}
    end.

read_partial_body(State, _Vsn, Hdrs, chunked) ->
    Window = State#client_state.download_window,
    read_partial_chunked_body(State, Hdrs, Window, 0, [], 0);
read_partial_body(State, Vsn, Hdrs, infinite) ->
    check_infinite_response(Vsn, Hdrs),
    read_partial_infinite_body(State, Hdrs, State#client_state.download_window);
read_partial_body(State, _Vsn, Hdrs, {fixed_length, ContentLength}) ->
    read_partial_finite_body(State, Hdrs, ContentLength,
        State#client_state.download_window).

read_body(_Vsn, Hdrs, Ssl, Socket, chunked) ->
    read_chunked_body(Socket, Ssl, Hdrs, []);
read_body(Vsn, Hdrs, Ssl, Socket, infinite) ->
    check_infinite_response(Vsn, Hdrs),
    read_infinite_body(Socket, Hdrs, Ssl);
read_body(_Vsn, Hdrs, Ssl, Socket, {fixed_length, ContentLength}) ->
    read_length(Hdrs, Ssl, Socket, ContentLength).

read_partial_finite_body(State = #client_state{}, Hdrs, 0, _Window) ->
    reply_end_of_body(State, [], Hdrs);
read_partial_finite_body(State = #client_state{requester = To}, Hdrs,
        ContentLength, 0) ->
    receive
        {ack, To} ->
            read_partial_finite_body(State, Hdrs, ContentLength, 1);
        {'DOWN', _, process, To, _} ->
            exit(normal)
    end;
read_partial_finite_body(State, Hdrs, ContentLength, Window) when Window >= 0->
    Bin = read_body_part(State, ContentLength),
    State#client_state.requester ! {body_part, self(), Bin},
    To = State#client_state.requester,
    receive
        {ack, To} ->
            Length = ContentLength - iolist_size(Bin),
            read_partial_finite_body(State, Hdrs, Length, Window);
        {'DOWN', _, process, To, _} ->
            exit(normal)
    after 0 ->
            Length = ContentLength - iolist_size(Bin),
        read_partial_finite_body(State, Hdrs, Length, lhttpc_lib:dec(Window))
    end.

read_body_part(#client_state{part_size = infinity} = State, _ContentLength) ->
    case lhttpc_sock:recv(State#client_state.socket, State#client_state.ssl) of
        {ok, Data} ->
            Data;
        {error, Reason} ->
            erlang:error(Reason)
    end;
read_body_part(#client_state{part_size = PartSize} = State, ContentLength)
        when PartSize =< ContentLength ->
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    PartSize = State#client_state.part_size,
    case lhttpc_sock:recv(Socket, PartSize, Ssl) of
        {ok, Data} ->
            Data;
        {error, Reason} ->
            erlang:error(Reason)
    end;
read_body_part(#client_state{part_size = PartSize} = State, ContentLength)
        when PartSize > ContentLength ->
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    case lhttpc_sock:recv(Socket, ContentLength, Ssl) of
        {ok, Data} ->
            Data;
        {error, Reason} ->
            erlang:error(Reason)
    end.

read_length(Hdrs, Ssl, Socket, Length) ->
    case lhttpc_sock:recv(Socket, Length, Ssl) of
        {ok, Data} ->
            {Data, Hdrs};
        {error, Reason} ->
            erlang:error(Reason)
    end.

read_partial_chunked_body(State, Hdrs, Window, BufferSize, Buffer, 0) ->
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    PartSize = State#client_state.part_size,
    case read_chunk_size(Socket, Ssl) of
        0 ->
            reply_chunked_part(State, Buffer, Window),
            {Trailers, NewHdrs} = read_trailers(Socket, Ssl, [], Hdrs),
            reply_end_of_body(State, Trailers, NewHdrs);
        ChunkSize when PartSize =:= infinity ->
            Chunk = read_chunk(Socket, Ssl, ChunkSize),
            NewWindow = reply_chunked_part(State, [Chunk | Buffer], Window),
            read_partial_chunked_body(State, Hdrs, NewWindow, 0, [], 0);
        ChunkSize when BufferSize + ChunkSize >= PartSize ->
            {Chunk, RemSize} = read_partial_chunk(Socket, Ssl,
                PartSize - BufferSize, ChunkSize),
            NewWindow = reply_chunked_part(State, [Chunk | Buffer], Window),
            read_partial_chunked_body(State, Hdrs, NewWindow, 0, [], RemSize);
        ChunkSize ->
            Chunk = read_chunk(Socket, Ssl, ChunkSize),
            read_partial_chunked_body(State, Hdrs, Window,
                BufferSize + ChunkSize, [Chunk | Buffer], 0)
    end;
read_partial_chunked_body(State, Hdrs, Window, BufferSize, Buffer, RemSize) ->
    Socket = State#client_state.socket,
    Ssl = State#client_state.ssl,
    PartSize = State#client_state.part_size,
    if
        BufferSize + RemSize >= PartSize ->
            {Chunk, NewRemSize} =
                read_partial_chunk(Socket, Ssl, PartSize - BufferSize, RemSize),
            NewWindow = reply_chunked_part(State, [Chunk | Buffer], Window),
            read_partial_chunked_body(State, Hdrs, NewWindow, 0, [],
                NewRemSize);
        BufferSize + RemSize < PartSize ->
            Chunk = read_chunk(Socket, Ssl, RemSize),
            read_partial_chunked_body(State, Hdrs, Window, BufferSize + RemSize,
                [Chunk | Buffer], 0)
    end.

read_chunk_size(Socket, Ssl) ->
    lhttpc_sock:setopts(Socket, [{packet, line}], Ssl),
    case lhttpc_sock:recv(Socket, Ssl) of
        {ok, ChunkSizeExt} ->
            chunk_size(ChunkSizeExt);
        {error, Reason} ->
            erlang:error(Reason)
    end.

reply_chunked_part(_State, [], Window) ->
    Window;
reply_chunked_part(State = #client_state{requester = Pid}, Buff, 0) ->
    receive
        {ack, Pid} ->
            reply_chunked_part(State, Buff, 1);
        {'DOWN', _, process, Pid, _} ->
            exit(normal)
    end;
reply_chunked_part(#client_state{requester = Pid}, Buffer, Window) ->
    Pid ! {body_part, self(), list_to_binary(lists:reverse(Buffer))},
    receive
        {ack, Pid} -> Window;
        {'DOWN', _, process, Pid, _} -> exit(normal)
    after 0 ->
        lhttpc_lib:dec(Window)
    end.

read_chunked_body(Socket, Ssl, Hdrs, Chunks) ->
    case read_chunk_size(Socket, Ssl) of
        0 ->
            Body = list_to_binary(lists:reverse(Chunks)),
            {_, NewHdrs} = read_trailers(Socket, Ssl, [], Hdrs),
            {Body, NewHdrs};
        Size ->
            Chunk = read_chunk(Socket, Ssl, Size),
            read_chunked_body(Socket, Ssl, Hdrs, [Chunk | Chunks])
    end.

chunk_size(Bin) ->
    erlang:list_to_integer(lists:reverse(chunk_size(Bin, [])), 16).

chunk_size(<<$;, _/binary>>, Chars) ->
    Chars;
chunk_size(<<"\r\n", _/binary>>, Chars) ->
    Chars;
chunk_size(<<$\s, Binary/binary>>, Chars) ->
    %% Facebook's HTTP server returns a chunk size like "6 \r\n"
    chunk_size(Binary, Chars);
chunk_size(<<Char, Binary/binary>>, Chars) ->
    chunk_size(Binary, [Char | Chars]).

read_partial_chunk(Socket, Ssl, ChunkSize, ChunkSize) ->
    {read_chunk(Socket, Ssl, ChunkSize), 0};
read_partial_chunk(Socket, Ssl, Size, ChunkSize) ->
    lhttpc_sock:setopts(Socket, [{packet, raw}], Ssl),
    case lhttpc_sock:recv(Socket, Size, Ssl) of
        {ok, Chunk} ->
            {Chunk, ChunkSize - Size};
        {error, Reason} ->
            erlang:error(Reason)
    end.

read_chunk(Socket, Ssl, Size) ->
    lhttpc_sock:setopts(Socket, [{packet, raw}], Ssl),
    case lhttpc_sock:recv(Socket, Size + 2, Ssl) of
        {ok, <<Chunk:Size/binary, "\r\n">>} ->
            Chunk;
        {ok, Data} ->
            erlang:error({invalid_chunk, Data});
        {error, Reason} ->
            erlang:error(Reason)
    end.

read_trailers(Socket, Ssl, Trailers, Hdrs) ->
    lhttpc_sock:setopts(Socket, [{packet, httph}], Ssl),
    case lhttpc_sock:recv(Socket, Ssl) of
        {ok, http_eoh} ->
            {Trailers, Hdrs};
        {ok, {http_header, _, Name, _, Value}} ->
            Header = {lhttpc_lib:maybe_atom_to_list(Name), Value},
            read_trailers(Socket, Ssl, [Header | Trailers], [Header | Hdrs]);
        {error, {http_error, Data}} ->
            erlang:error({bad_trailer, Data})
    end.

reply_end_of_body(#client_state{requester = Requester}, Trailers, Hdrs) ->
    Requester ! {http_eob, self(), Trailers},
    {no_return, Hdrs}.

read_partial_infinite_body(State = #client_state{requester = To}, Hdrs, 0) ->
    receive
        {ack, To} ->
            read_partial_infinite_body(State, Hdrs, 1);
        {'DOWN', _, process, To, _} ->
            exit(normal)
    end;
read_partial_infinite_body(State = #client_state{requester = To}, Hdrs, Window)
        when Window >= 0 ->
    case read_infinite_body_part(State) of
        http_eob -> reply_end_of_body(State, [], Hdrs);
        Bin ->
            State#client_state.requester ! {body_part, self(), Bin},
            receive
                {ack, To} ->
                    read_partial_infinite_body(State, Hdrs, Window);
                {'DOWN', _, process, To, _} ->
                    exit(normal)
            after 0 ->
                read_partial_infinite_body(State, Hdrs, lhttpc_lib:dec(Window))
            end
    end.

read_infinite_body_part(#client_state{socket = Socket, ssl = Ssl}) ->
    case lhttpc_sock:recv(Socket, Ssl) of
        {ok, Data} ->
            Data;
        {error, closed} ->
            http_eob;
        {error, Reason} ->
            erlang:error(Reason)
    end.

check_infinite_response({1, Minor}, Hdrs) when Minor >= 1 ->
    HdrValue = lhttpc_lib:header_value("connection", Hdrs, "keep-alive"),
    case string:to_lower(HdrValue) of
        "close" -> ok;
        _ -> erlang:error(no_content_length)
    end;
check_infinite_response(_, Hdrs) ->
    HdrValue = lhttpc_lib:header_value("connection", Hdrs, "close"),
    case string:to_lower(HdrValue) of
        "keep-alive" -> erlang:error(no_content_length);
        _ -> ok
    end.

read_infinite_body(Socket, Hdrs, Ssl) ->
    read_until_closed(Socket, <<>>, Hdrs, Ssl).

read_until_closed(Socket, Acc, Hdrs, Ssl) ->
    case lhttpc_sock:recv(Socket, Ssl) of
        {ok, Body} ->
            NewAcc = <<Acc/binary, Body/binary>>,
            read_until_closed(Socket, NewAcc, Hdrs, Ssl);
        {error, closed} ->
            {Acc, Hdrs};
        {error, Reason} ->
            erlang:error(Reason)
    end.

maybe_close_socket(Lb, Socket, {1, Minor}, ReqHdrs, RespHdrs) when Minor >= 1->
    ClientConnection = ?CONNECTION_HDR(ReqHdrs, "keep-alive"),
    ServerConnection = ?CONNECTION_HDR(RespHdrs, "keep-alive"),
    if
        ClientConnection =:= "close"; ServerConnection =:= "close" ->
            gen_server:cast(Lb, {remove, Socket}),
            undefined;
        ClientConnection =/= "close", ServerConnection =/= "close" ->
            Socket
    end;
maybe_close_socket(Lb, Socket, _, ReqHdrs, RespHdrs) ->
    ClientConnection = ?CONNECTION_HDR(ReqHdrs, "keep-alive"),
    ServerConnection = ?CONNECTION_HDR(RespHdrs, "close"),
    if
        ClientConnection =:= "close"; ServerConnection =/= "keep-alive" ->
            gen_server:cast(Lb, {remove, Socket}),
            undefined;
        ClientConnection =/= "close", ServerConnection =:= "keep-alive" ->
            Socket
    end.
Something went wrong with that request. Please try again.