Protocol::HTTP2::Client (original) (raw)

NAME

Protocol::HTTP2::Client - HTTP/2 client

SYNOPSIS

use Protocol::HTTP2::Client;

# Create client object
my $client = Protocol::HTTP2::Client->new;

# Prepare first request
$client->request(

    # HTTP/2 headers
    ':scheme'    => 'http',
    ':authority' => 'localhost:8000',
    ':path'      => '/',
    ':method'    => 'GET',

    # HTTP/1.1 headers
    headers      => [
        'accept'     => '*/*',
        'user-agent' => 'perl-Protocol-HTTP2/0.13',
    ],

    # Callback when receive server's response
    on_done => sub {
        my ( <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>e</mi><mi>a</mi><mi>d</mi><mi>e</mi><mi>r</mi><mi>s</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">headers, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span><span class="mord mathnormal">a</span><span class="mord mathnormal">d</span><span class="mord mathnormal">ers</span><span class="mpunct">,</span></span></span></span>data ) = @_;
        ...
    },
);

# Protocol::HTTP2 is just HTTP/2 protocol decoder/encoder
# so you must create connection yourself

use AnyEvent;
use AnyEvent::Socket;
use AnyEvent::Handle;
my $w = AnyEvent->condvar;

# Plain-text HTTP/2 connection
tcp_connect 'localhost', 8000, sub {
    my ($fh) = @_ or die "connection failed: $!\n";
    
    my $handle;
    $handle = AnyEvent::Handle->new(
        fh       => $fh,
        autocork => 1,
        on_error => sub {
            $_[0]->destroy;
            print "connection error\n";
            $w->send;
        },
        on_eof => sub {
            $handle->destroy;
            $w->send;
        }
    );

    # First write preface to peer
    while ( my <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>r</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">frame = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">am</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>client->next_frame ) {
        <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>−</mo><mo>&gt;</mo><mi>p</mi><mi>u</mi><mi>s</mi><msub><mi>h</mi><mi>w</mi></msub><mi>r</mi><mi>i</mi><mi>t</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">handle-&gt;push_write(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">p</span><span class="mord mathnormal">u</span><span class="mord mathnormal">s</span><span class="mord"><span class="mord mathnormal">h</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.1514em;"><span style="top:-2.55em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.02691em;">w</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mopen">(</span></span></span></span>frame);
    }

    # Receive servers frames
    # Reply to server
    $handle->on_read(
        sub {
            my $handle = shift;

            <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>l</mi><mi>i</mi><mi>e</mi><mi>n</mi><mi>t</mi><mo>−</mo><mo>&gt;</mo><mi>f</mi><mi>e</mi><mi>e</mi><mi>d</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">client-&gt;feed( </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">i</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">ee</span><span class="mord mathnormal">d</span><span class="mopen">(</span></span></span></span>handle->{rbuf} );

            $handle->{rbuf} = undef;
            while ( my <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>r</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">frame = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">am</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>client->next_frame ) {
                <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>−</mo><mo>&gt;</mo><mi>p</mi><mi>u</mi><mi>s</mi><msub><mi>h</mi><mi>w</mi></msub><mi>r</mi><mi>i</mi><mi>t</mi><mi>e</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">handle-&gt;push_write(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">p</span><span class="mord mathnormal">u</span><span class="mord mathnormal">s</span><span class="mord"><span class="mord mathnormal">h</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.1514em;"><span style="top:-2.55em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.02691em;">w</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">i</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mopen">(</span></span></span></span>frame);
            }

            # Terminate connection if all done
            <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>a</mi><mi>n</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo>−</mo><mo>&gt;</mo><mi>p</mi><mi>u</mi><mi>s</mi><msub><mi>h</mi><mi>s</mi></msub><mi>h</mi><mi>u</mi><mi>t</mi><mi>d</mi><mi>o</mi><mi>w</mi><mi>n</mi><mi>i</mi><mi>f</mi></mrow><annotation encoding="application/x-tex">handle-&gt;push_shutdown if </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">han</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">p</span><span class="mord mathnormal">u</span><span class="mord mathnormal">s</span><span class="mord"><span class="mord mathnormal">h</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.1514em;"><span style="top:-2.55em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight">s</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal">h</span><span class="mord mathnormal">u</span><span class="mord mathnormal">t</span><span class="mord mathnormal">d</span><span class="mord mathnormal">o</span><span class="mord mathnormal" style="margin-right:0.02691em;">w</span><span class="mord mathnormal">ni</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span></span></span></span>client->shutdown;
        }
    );
};

$w->recv;

DESCRIPTION

Protocol::HTTP2::Client is HTTP/2 client library. It's intended to make http2-client implementations on top of your favorite event-loop.

METHODS

new

Initialize new client object

my $client = Protocol::HTTP2::Client->new( %options );

Available options:

on_push => sub {...}

If server send push promise this callback will be invoked

on_push => sub {
    # received PUSH PROMISE headers
    my $pp_header = shift;
    ...

    # if we want reject this push
    # return undef

    # if we want to accept pushed resource
    # return callback to receive data
    return sub {
        my ( <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>e</mi><mi>a</mi><mi>d</mi><mi>e</mi><mi>r</mi><mi>s</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">headers, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span><span class="mord mathnormal">a</span><span class="mord mathnormal">d</span><span class="mord mathnormal">ers</span><span class="mpunct">,</span></span></span></span>data ) = @_;
        ...
    }
},

upgrade => 0|1

Use HTTP/1.1 Upgrade to upgrade protocol from HTTP/1.1 to HTTP/2. Upgrade possible only on plain (non-tls) connection. Default value is 0.

See Starting HTTP/2 for "http" URIs

keepalive => 0|1

Keep connection alive after requests. Default value is 0. Don't forget to explicitly call close method if set this to true.

on_error => sub {...}

Callback invoked on protocol errors

on_error => sub {
    my $error = shift;
    ...
},

on_change_state => sub {...}

Callback invoked every time when http/2 streams change their state. See Stream States

on_change_state => sub {
    my ( <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>t</mi><mi>r</mi><mi>e</mi><mi>a</mi><msub><mi>m</mi><mi>i</mi></msub><mi>d</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">stream_id, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">s</span><span class="mord mathnormal">t</span><span class="mord mathnormal">re</span><span class="mord mathnormal">a</span><span class="mord"><span class="mord mathnormal">m</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3117em;"><span style="top:-2.55em;margin-left:0em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight">i</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal">d</span><span class="mpunct">,</span></span></span></span>previous_state, $current_state ) = @_;
    ...
},

request

Prepare HTTP/2 request.

$client->request(

    # HTTP/2 headers
    ':scheme'    => 'http',
    ':authority' => 'localhost:8000',
    ':path'      => '/items',
    ':method'    => 'POST',

    # HTTP/1.1 headers
    headers      => [
        'content-type' => 'application/x-www-form-urlencoded',
        'user-agent' => 'perl-Protocol-HTTP2/0.06',
    ],

    # Callback when receive server's response
    on_done => sub {
        my ( <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>e</mi><mi>a</mi><mi>d</mi><mi>e</mi><mi>r</mi><mi>s</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">headers, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span><span class="mord mathnormal">a</span><span class="mord mathnormal">d</span><span class="mord mathnormal">ers</span><span class="mpunct">,</span></span></span></span>data ) = @_;
        ...
    },

    # Callback when receive stream reset
    on_error => sub {
        my $error_code = shift;
    },

    # Body of POST request
    data => "hello=world&test=done",
);

You can chaining request one by one:

$client->request( 1-st request )->request( 2-nd request );

Available callbacks:

on_done => sub {...}

Invoked when full servers response is available

on_done => sub {
    my ( <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>h</mi><mi>e</mi><mi>a</mi><mi>d</mi><mi>e</mi><mi>r</mi><mi>s</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">headers, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">h</span><span class="mord mathnormal">e</span><span class="mord mathnormal">a</span><span class="mord mathnormal">d</span><span class="mord mathnormal">ers</span><span class="mpunct">,</span></span></span></span>data ) = @_;
    ...
},

Invoked as soon as headers have been successfully received from the server

on_headers => sub {
    my $headers = shift;
    ...

    # if we want reject any data
    # return undef

    # continue
    return 1
}

on_data => sub {...}

If specified all data will be passed to this callback instead if on_done. on_done will receive empty string.

on_data => sub {
    my ( <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>p</mi><mi>a</mi><mi>r</mi><mi>t</mi><mi>i</mi><mi>a</mi><msub><mi>l</mi><mi>d</mi></msub><mi>a</mi><mi>t</mi><mi>a</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">partial_data, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">p</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">t</span><span class="mord mathnormal">ia</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3361em;"><span style="top:-2.55em;margin-left:-0.0197em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight">d</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal">a</span><span class="mord mathnormal">t</span><span class="mord mathnormal">a</span><span class="mpunct">,</span></span></span></span>headers ) = @_;
    ...

    # if we want cancel download
    # return undef

    # continue downloading
    return 1
}

on_error => sub {...}

Callback invoked on stream errors

on_error => sub {
    my $error = shift;
    ...
}

keepalive

Keep connection alive after requests

my <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>b</mi><mi>o</mi><mi>o</mi><mi>l</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">bool = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">b</span><span class="mord mathnormal">oo</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>client->keepalive; <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>l</mi><mi>i</mi><mi>e</mi><mi>n</mi><mi>t</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">client = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">i</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>client->keepalive($bool);

shutdown

Get connection status:

0 - active

1 - closed (you can terminate connection)

close

Explicitly close connection (send GOAWAY frame). This is required if client has keepalive option enabled.

next_frame

get next frame to send over connection to server. Returns:

undef - on error

0 - nothing to send

binary string - encoded frame

# Example
while ( my <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>r</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">frame = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord mathnormal">am</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>client->next_frame ) {
    syswrite <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>h</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">fh, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">h</span><span class="mpunct">,</span></span></span></span>frame;
}

feed

Feed decoder with chunks of server's response

sysread <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>h</mi><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">fh, </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">h</span><span class="mpunct">,</span></span></span></span>binary_data, 4096; <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>l</mi><mi>i</mi><mi>e</mi><mi>n</mi><mi>t</mi><mo>−</mo><mo>&gt;</mo><mi>f</mi><mi>e</mi><mi>e</mi><mi>d</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">client-&gt;feed(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">c</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">i</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">ee</span><span class="mord mathnormal">d</span><span class="mopen">(</span></span></span></span>binary_data);

ping

Send ping frame to server (to keep connection alive)

$client->ping

Payload can be arbitrary binary string and must contain 8 octets. If payload argument is omitted client will send random data.