Fast and Ultra Slim Connection Oriented HTTP Client
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Fast and Ultra Slim Connection Oriented HTTP Client

Fusco is an Erlang HTTP client for high performance applications. For all those who need a generic HTTP client, check lhttpc in which development is based Fusco. Not all the functionalities of lhttpc are present here.

Fusco is still in a very early stage of development, be aware of that!


Assume that you have a web server at, and you want to perform GET /example. For that you need to:

  1. Spawn client (client is just a pid)
1> {ok, Client} = fusco:start("", []).
  1. Use request function - we perform GET /example so:
2> {ok, Result} = fusco:request(Client, <<"/example">>, <<"GET">>, [], [], 5000).
  1. After all request to server - close the connection:
3> fusco:disconnect(Client).


To perform request you need only to know 3 functions from fusco module:

  • start/2 - spawns a new Client (a gen_server) which is associated to server on Host
start(Host :: string(), Options :: []) -> {ok, Client :: pid()}
  • request/6 - makes a request on a Path of Host of web server which is Client associated for. Every Path must be preceeded by /. Methods must be written in uppercase e.g. <<"GET">>
request(Client, Path, Method, Headers, Body, Timeout) -> Result

Client = pid()
Host = binary()
Method = binary()
Hdrs = [{Header, Value}]
Header = string() | binary() | atom()
Value = string() | binary()
RequestBody = iodata()
RetryCount = integer()
Timeout = integer() | infinity
Result = {ok, {{StatusCode, ReasonPhrase}, Hdrs, ResponseBody}}
         | {error, Reason}
StatusCode = integer()
ReasonPhrase = string()
ResponseBody = binary() | pid() | undefined
Reason = connection_closed | connect_timeout | timeout

Possible Options for start function:

{connect_timeout, Milliseconds} specifies how many milliseconds the client can spend trying to establish a connection to the server. This doesn't affect the overall request timeout. However, if it's longer than the overall timeout it will be ignored. Also note that the TCP layer may choose to give up earlier than the connect timeout, in which case the client will also give up. The default value is infinity, which means that it will either give up when the TCP stack gives up, or when the overall request timeout is reached.

{connect_options, Options} specifies options to pass to the socket at connect time. This makes it possible to specify both SSL options and regular socket options, such as which IP/Port to connect from etc. Some options must not be included here, namely the mode, binary or list, {active, boolean()}, {active, once} or {packet, Packet}. These options would confuse the client if they are included. Please note that these options will only have an effect on new connections, and it isn't possible for different requests to the same host uses different options unless the connection is closed between the requests. Using HTTP/1.0 or including the "Connection: close" header would make the client close the connection after the first response is received.

{send_retry, N} specifies how many times the client should retry sending a request if the connection is closed after the data has been sent. The default value is 1.

{proxy, ProxyUrl} if this option is specified, a proxy server is used as an intermediary for all communication with the destination server. The link to the proxy server is established with the HTTP CONNECT method (RFC2817). Example value: {proxy, ""}

{proxy_ssl_options, SslOptions} this is a list of SSL options to use for the SSL session created after the proxy connection is established. For a list of all available options, please check OTP's ssl module manpage.

  • disconnect/1 - disconnects the Client from server. After that it kills the Client process
disconnect(Client :: pid())

Running Tests

You can execute all test with

> make test

And you can check this repo and run the Erlang QuickCheck tests