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NAME
    AnyEvent::HTTP - simple but non-blocking HTTP/HTTPS client

SYNOPSIS
       use AnyEvent::HTTP;

       http_get "http://www.nethype.de/", sub { print $_[1] };

       # ... do something else here

DESCRIPTION
    This module is an AnyEvent user, you need to make sure that you use and
    run a supported event loop.

    This module implements a simple, stateless and non-blocking HTTP client.
    It supports GET, POST and other request methods, cookies and more, all
    on a very low level. It can follow redirects, supports proxies, and
    automatically limits the number of connections to the values specified
    in the RFC.

    It should generally be a "good client" that is enough for most HTTP
    tasks. Simple tasks should be simple, but complex tasks should still be
    possible as the user retains control over request and response headers.

    The caller is responsible for authentication management, cookies (if the
    simplistic implementation in this module doesn't suffice), referer and
    other high-level protocol details for which this module offers only
    limited support.

  METHODS
    http_get $url, key => value..., $cb->($data, $headers)
        Executes an HTTP-GET request. See the http_request function for
        details on additional parameters and the return value.

    http_head $url, key => value..., $cb->($data, $headers)
        Executes an HTTP-HEAD request. See the http_request function for
        details on additional parameters and the return value.

    http_post $url, $body, key => value..., $cb->($data, $headers)
        Executes an HTTP-POST request with a request body of $body. See the
        http_request function for details on additional parameters and the
        return value.

    http_request $method => $url, key => value..., $cb->($data, $headers)
        Executes a HTTP request of type $method (e.g. "GET", "POST"). The
        URL must be an absolute http or https URL.

        When called in void context, nothing is returned. In other contexts,
        "http_request" returns a "cancellation guard" - you have to keep the
        object at least alive until the callback get called. If the object
        gets destroyed before the callback is called, the request will be
        cancelled.

        The callback will be called with the response body data as first
        argument (or "undef" if an error occurred), and a hash-ref with
        response headers (and trailers) as second argument.

        All the headers in that hash are lowercased. In addition to the
        response headers, the "pseudo-headers" (uppercase to avoid clashing
        with possible response headers) "HTTPVersion", "Status" and "Reason"
        contain the three parts of the HTTP Status-Line of the same name. If
        an error occurs during the body phase of a request, then the
        original "Status" and "Reason" values from the header are available
        as "OrigStatus" and "OrigReason".

        The pseudo-header "URL" contains the actual URL (which can differ
        from the requested URL when following redirects - for example, you
        might get an error that your URL scheme is not supported even though
        your URL is a valid http URL because it redirected to an ftp URL, in
        which case you can look at the URL pseudo header).

        The pseudo-header "Redirect" only exists when the request was a
        result of an internal redirect. In that case it is an array
        reference with the "($data, $headers)" from the redirect response.
        Note that this response could in turn be the result of a redirect
        itself, and "$headers->{Redirect}[1]{Redirect}" will then contain
        the original response, and so on.

        If the server sends a header multiple times, then their contents
        will be joined together with a comma (","), as per the HTTP spec.

        If an internal error occurs, such as not being able to resolve a
        hostname, then $data will be "undef", "$headers->{Status}" will be
        590-599 and the "Reason" pseudo-header will contain an error
        message. Currently the following status codes are used:

        595 - errors during connection establishment, proxy handshake.
        596 - errors during TLS negotiation, request sending and header
        processing.
        597 - errors during body receiving or processing.
        598 - user aborted request via "on_header" or "on_body".
        599 - other, usually nonretryable, errors (garbled URL etc.).

        A typical callback might look like this:

           sub {
              my ($body, $hdr) = @_;

              if ($hdr->{Status} =~ /^2/) {
                 ... everything should be ok
              } else {
                 print "error, $hdr->{Status} $hdr->{Reason}\n";
              }
           }

        Additional parameters are key-value pairs, and are fully optional.
        They include:

        recurse => $count (default: $MAX_RECURSE)
            Whether to recurse requests or not, e.g. on redirects,

README  view on Meta::CPAN

            code of 598).

            The downside to cancelling the request is that it makes it
            impossible to re-use the connection.

            This callback is useful when the data is too large to be held in
            memory (so the callback writes it to a file) or when only some
            information should be extracted, or when the body should be
            processed incrementally.

            It is usually preferred over doing your own body handling via
            "want_body_handle", but in case of streaming APIs, where HTTP is
            only used to create a connection, "want_body_handle" is the
            better alternative, as it allows you to install your own event
            handler, reducing resource usage.

        want_body_handle => $enable
            When enabled (default is disabled), the behaviour of
            AnyEvent::HTTP changes considerably: after parsing the headers,
            and instead of downloading the body (if any), the completion
            callback will be called. Instead of the $body argument
            containing the body data, the callback will receive the
            AnyEvent::Handle object associated with the connection. In error
            cases, "undef" will be passed. When there is no body (e.g.
            status 304), the empty string will be passed.

            The handle object might or might not be in TLS mode, might be
            connected to a proxy, be a persistent connection, use chunked
            transfer encoding etc., and configured in unspecified ways. The
            user is responsible for this handle (it will not be used by this
            module anymore).

            This is useful with some push-type services, where, after the
            initial headers, an interactive protocol is used (typical
            example would be the push-style twitter API which starts a
            JSON/XML stream).

            If you think you need this, first have a look at "on_body", to
            see if that doesn't solve your problem in a better way.

        persistent => $boolean
            Try to create/reuse a persistent connection. When this flag is
            set (default: true for idempotent requests, false for all
            others), then "http_request" tries to re-use an existing
            (previously-created) persistent connection to same host (i.e.
            identical URL scheme, hostname, port and sessionid) and, failing
            that, tries to create a new one.

            Requests failing in certain ways will be automatically retried
            once, which is dangerous for non-idempotent requests, which is
            why it defaults to off for them. The reason for this is because
            the bozos who designed HTTP/1.1 made it impossible to
            distinguish between a fatal error and a normal connection
            timeout, so you never know whether there was a problem with your
            request or not.

            When reusing an existent connection, many parameters (such as
            TLS context) will be ignored. See the "sessionid" parameter for
            a workaround.

        keepalive => $boolean
            Only used when "persistent" is also true. This parameter decides
            whether "http_request" tries to handshake a HTTP/1.0-style
            keep-alive connection (as opposed to only a HTTP/1.1 persistent
            connection).

            The default is true, except when using a proxy, in which case it
            defaults to false, as HTTP/1.0 proxies cannot support this in a
            meaningful way.

        handle_params => { key => value ... }
            The key-value pairs in this hash will be passed to any
            AnyEvent::Handle constructor that is called - not all requests
            will create a handle, and sometimes more than one is created, so
            this parameter is only good for setting hints.

            Example: set the maximum read size to 4096, to potentially
            conserve memory at the cost of speed.

               handle_params => {
                  max_read_size => 4096,
               },

        Example: do a simple HTTP GET request for http://www.nethype.de/ and
        print the response body.

           http_request GET => "http://www.nethype.de/", sub {
              my ($body, $hdr) = @_;
              print "$body\n";
           };

        Example: do a HTTP HEAD request on https://www.google.com/, use a
        timeout of 30 seconds.

           http_request
              HEAD    => "https://www.google.com",
              headers => { "user-agent" => "MySearchClient 1.0" },
              timeout => 30,
              sub {
                 my ($body, $hdr) = @_;
                 use Data::Dumper;
                 print Dumper $hdr;
              }
           ;

        Example: do another simple HTTP GET request, but immediately try to
        cancel it.

           my $request = http_request GET => "http://www.nethype.de/", sub {
              my ($body, $hdr) = @_;
              print "$body\n";
           };

           undef $request;

  DNS CACHING
    AnyEvent::HTTP uses the AnyEvent::Socket::tcp_connect function for the
    actual connection, which in turn uses AnyEvent::DNS to resolve
    hostnames. The latter is a simple stub resolver and does no caching on
    its own. If you want DNS caching, you currently have to provide your own
    default resolver (by storing a suitable resolver object in
    $AnyEvent::DNS::RESOLVER) or your own "tcp_connect" callback.

  GLOBAL FUNCTIONS AND VARIABLES