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Add simple http client
Add simple http client that can be used in different situations, such as when performing updates, inspired to Mint Elixir http client. Signed-off-by: Davide Bettio <[email protected]>
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‎CHANGELOG.md

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@@ -10,6 +10,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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- Fix bug in `erlang:ref_to_list/1`, the unique integer was truncated on some 32-bit architectures
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### Added
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- Simple http client, that can be used for different use case such as downloading OTA updates
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## [0.6.0] - 2024-03-05
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### Fixed

‎examples/erlang/CMakeLists.txt

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@@ -40,3 +40,4 @@ pack_runnable(code_lock code_lock estdlib eavmlib)
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pack_runnable(mqtt_client mqtt_client estdlib eavmlib)
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pack_runnable(network_console network_console estdlib eavmlib alisp)
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pack_runnable(logging_example logging_example estdlib eavmlib)
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pack_runnable(http_client http_client estdlib eavmlib)

‎examples/erlang/http_client.erl

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%
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% This file is part of AtomVM.
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%
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% Copyright 2024 Davide Bettio <[email protected]>
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%
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% Licensed under the Apache License, Version 2.0 (the "License");
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% you may not use this file except in compliance with the License.
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% You may obtain a copy of the License at
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%
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% http://www.apache.org/licenses/LICENSE-2.0
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%
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% Unless required by applicable law or agreed to in writing, software
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% distributed under the License is distributed on an "AS IS" BASIS,
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% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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% See the License for the specific language governing permissions and
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% limitations under the License.
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%
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% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
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%
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-module(http_client).
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-export([start/0]).
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start() ->
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{ok, Conn} = ahttp_client:connect(http, "localhost", 8000, []),
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{ok, Conn2, _Ref} = ahttp_client:request(Conn, <<"GET">>, <<"/">>, [], undefined),
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loop(Conn2).
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loop(Conn) ->
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receive
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Message ->
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case ahttp_client:stream(Conn, Message) of
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{ok, _Conn, closed} ->
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io:format("Connection closed.~n");
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{ok, UpdatedConn, Responses} ->
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io:format("Got: ~p~n", [Responses]),
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loop(UpdatedConn);
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unknown ->
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io:format("Unexpected message: ~p~n", [Message])
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end
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end.

‎libs/eavmlib/src/CMakeLists.txt

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@@ -23,6 +23,7 @@ project(eavmlib)
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include(BuildErlang)
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set(ERLANG_MODULES
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ahttp_client
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atomvm
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avm_pubsub
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console

‎libs/eavmlib/src/ahttp_client.erl

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%
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% This file is part of AtomVM.
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%
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% Copyright 2024 Davide Bettio <[email protected]>
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%
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% Licensed under the Apache License, Version 2.0 (the "License");
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% you may not use this file except in compliance with the License.
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% You may obtain a copy of the License at
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%
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% http://www.apache.org/licenses/LICENSE-2.0
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%
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% Unless required by applicable law or agreed to in writing, software
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% distributed under the License is distributed on an "AS IS" BASIS,
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% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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% See the License for the specific language governing permissions and
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% limitations under the License.
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%
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% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
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%
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-module(ahttp_client).
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-export([connect/4, request/5, stream/2]).
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-define(DEFAULT_WANTED_HEADERS, [<<"Content-Length">>]).
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-record(http_client, {host, socket, parser, ref}).
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-record(parser_state, {state, acc, remaining_body_bytes, wanted_headers = ?DEFAULT_WANTED_HEADERS}).
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connect(Protocol, Host, Port, Options) when is_binary(Host) ->
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connect(Protocol, binary_to_list(Host), Port, Options);
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connect(http, Host, Port, _Options) ->
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{ok, Sock} = gen_tcp:connect(Host, Port, [binary, {active, true}]),
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{ok, #http_client{host = list_to_binary(Host), socket = {gen_tcp, Sock}}}.
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request(#http_client{host = Host, socket = TSocket} = Conn, Method, Path, Headers, Body) ->
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{BodyBin, MaybeBodyHeaders} = prepare_body(Body, Headers),
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HeadersBin = transform_headers(MaybeBodyHeaders),
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Data =
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<<Method/binary, " ", Path/binary,
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" HTTP/1.1\r\n"
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"Host: ", Host/binary, "\r\n", HeadersBin/binary, "\r\n", BodyBin/binary>>,
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{gen_tcp, TCPSocket} = TSocket,
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case gen_tcp:send(TCPSocket, Data) of
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ok ->
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Ref = make_ref(),
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{ok, Conn#http_client{ref = Ref}, Ref};
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_ ->
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error
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end.
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prepare_body(undefined, Headers) ->
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{<<"">>, Headers};
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prepare_body(nil, Headers) ->
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{<<"">>, Headers};
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prepare_body(Body, Headers) ->
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BodyLen = integer_to_binary(byte_size(Body)),
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{Body, [{<<"content-length">>, BodyLen} | Headers]}.
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transform_headers([]) ->
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<<"">>;
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transform_headers([{Name, Value} | Tail]) ->
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Bin = transform_headers(Tail),
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<<Name/binary, ": ", Value/binary, "\r\n", Bin/binary>>.
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stream(#http_client{socket = {gen_tcp, TSocket}, parser = Parser} = Conn, {tcp, TSocket, Chunk}) ->
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{ok, UpdatedParser, Parsed} = feed_parser(Parser, Chunk),
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Responses = make_responses(Parsed, Conn#http_client.ref, []),
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{ok, Conn#http_client{parser = UpdatedParser}, Responses};
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stream(#http_client{socket = {gen_tcp, TSocket}} = Conn, {tcp_closed, TSocket}) ->
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{ok, Conn, closed};
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stream(_Conn, _Other) ->
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unknown.
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make_responses([], _Ref, Acc) ->
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Acc;
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make_responses([Response | Tail], Ref, Acc) when is_atom(Response) ->
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make_responses(Tail, Ref, [{Response, Ref} | Acc]);
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make_responses([{Tag, Value} | Tail], Ref, Acc) ->
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make_responses(Tail, Ref, [{Tag, Ref, Value} | Acc]).
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feed_parser(undefined, Chunk) ->
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feed_parser(#parser_state{}, Chunk);
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feed_parser(#parser_state{state = body} = Parser, Chunk) ->
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consume_bytes(append_chunk(Parser, Chunk), []);
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feed_parser(Parser, Chunk) ->
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consume_lines(append_chunk(Parser, Chunk), []).
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consume_bytes(#parser_state{acc = undefined} = Parser, ParsedAcc) ->
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{ok, Parser, ParsedAcc};
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consume_bytes(#parser_state{acc = Chunk} = Parser, ParsedAcc) when is_binary(Chunk) ->
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ReplacedAccParser = replace_chunk(Parser, undefined),
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NewRemBodyBytes = maybe_decrement(
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ReplacedAccParser#parser_state.remaining_body_bytes, byte_size(Chunk)
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),
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{UpdatedParser, Parsed} = maybe_handle_end_of_response(
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ReplacedAccParser#parser_state{remaining_body_bytes = NewRemBodyBytes}, [
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{data, Chunk} | ParsedAcc
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]
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),
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{ok, UpdatedParser, Parsed}.
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consume_lines(Parser, ParsedAcc) ->
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case binary:split(Parser#parser_state.acc, <<"\r\n">>) of
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[_NotTerminatedLine] ->
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{ok, Parser, ParsedAcc};
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[Line, Rest] ->
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ReplacedAccParser = replace_chunk(Parser, Rest),
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case parse_line(ReplacedAccParser, Line) of
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{consume_bytes, UpdatedParser} ->
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consume_bytes(UpdatedParser, ParsedAcc);
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{ok, UpdatedParser} ->
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consume_lines(UpdatedParser, ParsedAcc);
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{ok, UpdatedParser, Found} ->
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consume_lines(UpdatedParser, [Found | ParsedAcc]);
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{error, UpdatedParser, NotParsed} ->
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{error, UpdatedParser, ParsedAcc, NotParsed}
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end
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end.
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append_chunk(#parser_state{acc = undefined} = Parser, Chunk) ->
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Parser#parser_state{acc = Chunk};
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append_chunk(#parser_state{acc = Acc} = Parser, Chunk) ->
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Parser#parser_state{acc = <<Acc/binary, Chunk/binary>>}.
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replace_chunk(Parser, <<>>) ->
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Parser#parser_state{acc = undefined};
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replace_chunk(Parser, Chunk) ->
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Parser#parser_state{acc = Chunk}.
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parse_line(
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#parser_state{state = undefined} = Parser, <<"HTTP/1.0 ", C:3/binary, " ", _Txt/binary>>
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) ->
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StatusCode = binary_to_integer(C),
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{ok, Parser#parser_state{state = headers}, {status, StatusCode}};
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parse_line(
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#parser_state{state = undefined} = Parser, <<"HTTP/1.1 ", C:3/binary, " ", _Txt/binary>>
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) ->
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StatusCode = binary_to_integer(C),
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{ok, Parser#parser_state{state = headers}, {status, StatusCode}};
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parse_line(#parser_state{state = headers} = Parser, <<>>) ->
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{consume_bytes, Parser#parser_state{state = body}};
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parse_line(#parser_state{state = headers, wanted_headers = WantedHeaders} = Parser, HeaderLine) ->
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case split_header(WantedHeaders, HeaderLine) of
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{ok, Name, Value} ->
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TrimmedValue = trim_left_spaces(Value, 0),
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UpdatedParser =
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case Name of
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<<"Content-Length">> ->
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RemainingLen = binary_to_integer(TrimmedValue),
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Parser#parser_state{remaining_body_bytes = RemainingLen};
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_ ->
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Parser
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end,
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{ok, UpdatedParser, {header, {Name, TrimmedValue}}};
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ignore ->
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{ok, Parser};
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error ->
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{error, Parser, HeaderLine}
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end;
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parse_line(Parser, Any) ->
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{error, Parser, Any}.
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trim_left_spaces(Bin, Count) ->
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case Bin of
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<<_Bin:Count/binary, $\s, _Rest/binary>> ->
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trim_left_spaces(Bin, Count + 1);
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<<_Bin:Count/binary, NoLeftSpaces/binary>> ->
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NoLeftSpaces
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end.
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maybe_decrement(undefined, _B) ->
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undefined;
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maybe_decrement(A, B) ->
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A - B.
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maybe_handle_end_of_response(#parser_state{remaining_body_bytes = 0} = ParserState, AlreadyParsed) ->
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{ParserState#parser_state{state = done}, [done | AlreadyParsed]};
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maybe_handle_end_of_response(ParserState, AlreadyParsed) ->
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{ParserState, AlreadyParsed}.
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split_header(all, HeaderLine) ->
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case binary:split(HeaderLine, <<":">>) of
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[_Invalid, <<>>] -> error;
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[Name, Value] -> {ok, Name, Value};
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_ -> error
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end;
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split_header([], _HeaderLine) ->
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ignore;
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split_header([Name | Tail], HeaderLine) ->
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NameLen = byte_size(Name),
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case HeaderLine of
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<<Name:NameLen/binary, $:, Value/binary>> -> {ok, Name, Value};
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_NotMatched -> split_header(Tail, HeaderLine)
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end.

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