Net::Async::HTTP - use HTTP with IO::Async


 use IO::Async::Loop;
 use Net::Async::HTTP;
 use URI;

 my $loop = IO::Async::Loop->new();

 my $http = Net::Async::HTTP->new();

 $loop->add( $http );

    uri => URI->new( "" ),

    on_response => sub {
       my ( $response ) = @_;
       print "Front page of is:\n";
       print $response->as_string;

    on_error => sub {
       my ( $message ) = @_;
       print "Cannot fetch - $message\n";



This object class implements an asynchronous HTTP user agent. It sends requests to servers, and invokes continuation callbacks when responses are received. The object supports multiple concurrent connections to servers, and allows multiple outstanding requests in pipeline to any one connection. Normally, only one such object will be needed per program to support any number of requests.

This module optionally supports SSL connections, if IO::Async::SSL is installed. If so, SSL can be requested either by passing a URI with the https scheme, or by passing the a true value as the SSL parameter.


The following named parameters may be passed to new or configure:

user_agent => STRING

A string to set in the User-Agent HTTP header. If not supplied, one will be constructed that declares Net::Async::HTTP and the version number.

max_redirects => INT

Optional. How many levels of redirection to follow. If not supplied, will default to 3. Give 0 to disable redirection entirely.

proxy_host => STRING
proxy_port => INT

Optional. Default values to apply to each request method.

Optional. A reference to a HTTP::Cookies object. Will be used to set cookies in requests and store them from responses.


$http->do_request( %args )

Send an HTTP request to a server, and set up the callbacks to receive a reply. The request may be represented by an HTTP::Request object, or a URI object, depending on the arguments passed.

The following named arguments are used for HTTP::Requests:

request => HTTP::Request

A reference to an HTTP::Request object

host => STRING
port => INT

Hostname and port number of the server to connect to


Optional. If true, an SSL connection will be used.

The following named arguments are used for URI requests:

uri => URI

A reference to a URI object. If the scheme is https then an SSL connection will be used.

method => STRING

Optional. The HTTP method. If missing, GET is used.

content => STRING or ARRAY ref

Optional. The body content to use for POST requests. If this is a plain scalar instead of an ARRAY ref, it will not be form encoded. In this case, a content_type field must also be supplied to describe it.

request_body => CODE or STRING

Optional. Allows request body content to be generated by a callback, rather than being provided as part of the request object. This can either be a CODE reference to a generator function, or a plain string.

As this is passed to the underlying IO::Async::Stream write method, the usual semantics apply here. If passed a CODE reference, it will be called repeatedly whenever it's safe to write. The code should should return undef to indicate completion.

As with the content parameter, the content_type field should be specified explicitly in the request header, as should the content length (typically via the HTTP::Request content_length method). See also examples/

content_type => STRING

The type of non-form data content.

user => STRING
pass => STRING

Optional. If both are given, the HTTP Basic Authorization header will be sent with these details.

proxy_host => STRING
proxy_port => INT

Optional. Override the hostname or port number implied by the URI.

For either request type, it takes the following continuation callbacks:

on_response => CODE

A callback that is invoked when a response to this request has been received. It will be passed an HTTP::Response object containing the response the server sent.

 $on_response->( $response )
on_header => CODE

Alternative to on_response. A callback that is invoked when the header of a response has been received. It is expected to return a CODE reference for handling chunks of body content. This CODE reference will be invoked with no arguments once the end of the request has been reached.

 $on_body_chunk = $on_header->( $header )

    $on_body_chunk->( $data )
on_error => CODE

A callback that is invoked if an error occurs while trying to send the request or obtain the response. It will be passed an error message.

 $on_error->( $message )
on_redirect => CODE

Optional. A callback that is invoked if a redirect response is received, before the new location is fetched. It will be passed the response and the new URL.

 $on_redirect->( $response, $location )
max_redirects => INT

Optional. How many levels of redirection to follow. If not supplied, will default to the value given in the constructor.


The following methods are intended as points for subclasses to override, to add extra functionallity.

$http->prepare_request( $request )

Called just before the HTTP::Request object is sent to the server.

$http->process_response( $response )

Called after a non-redirect HTTP::Response has been received from a server. The originating request will be set in the object.



Paul Evans <>