php-doc-en/reference/sockets/functions/socket-recv.xml
Daniel Egeberg 96c9d88bad Converted to utf-8
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2010-03-28 22:10:10 +00:00

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<?xml version="1.0" encoding="utf-8"?>
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<refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.socket-recv">
<refnamediv>
<refname>socket_recv</refname>
<refpurpose>Receives data from a connected socket </refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>int</type><methodname>socket_recv</methodname>
<methodparam><type>resource</type><parameter>socket</parameter></methodparam>
<methodparam><type>string</type><parameter role="reference">buf</parameter></methodparam>
<methodparam><type>int</type><parameter>len</parameter></methodparam>
<methodparam><type>int</type><parameter>flags</parameter></methodparam>
</methodsynopsis>
<para>
The <function>socket_recv</function> function receives
<parameter>len</parameter> bytes of data in <parameter>buf</parameter> from
<parameter>socket</parameter>. <function>socket_recv</function> can
be used to gather data from connected sockets. Additionally, one or
more flags can be specified to modify the behaviour of the
function.
</para>
<para>
<parameter>buf</parameter> is passed by reference, so it must be
specified as a variable in the argument list. Data read from
<parameter>socket</parameter> by <function>socket_recv</function>
will be returned in <parameter>buf</parameter>.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>socket</parameter></term>
<listitem>
<para>
The <parameter>socket</parameter> must be a socket resource previously
created by socket_create().
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buf</parameter></term>
<listitem>
<para>
The data received will be fetched to the variable specified with
<parameter>buf</parameter>. If an error occurs, if the
connection is reset, or if no data is
available, <parameter>buf</parameter> will be set to &null;.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>len</parameter></term>
<listitem>
<para>
Up to <parameter>len</parameter> bytes will be fetched from remote host.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>flags</parameter></term>
<listitem>
<para>
The value of <parameter>flags</parameter> can be any combination of
the following flags, joined with the binary OR (<literal>|</literal>)
operator.
</para>
<table>
<title>Possible values for <parameter>flags</parameter></title>
<tgroup cols="2">
<thead>
<row>
<entry>Flag</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><constant>MSG_OOB</constant></entry>
<entry>
Process out-of-band data.
</entry>
</row>
<row>
<entry><constant>MSG_PEEK</constant></entry>
<entry>
Receive data from the beginning of the receive queue without
removing it from the queue.
</entry>
</row>
<row>
<entry><constant>MSG_WAITALL</constant></entry>
<entry>
Block until at least <parameter>len</parameter> are received.
However, if a signal is caught or the remote host disconnects, the
function may return less data.
</entry>
</row>
<row>
<entry><constant>MSG_DONTWAIT</constant></entry>
<entry>
With this flag set, the function returns even if it would normally
have blocked.
</entry>
</row>
</tbody>
</tgroup>
</table>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
<function>socket_recv</function> returns the number of bytes received,
or &false; if there was an error. The actual error code can be retrieved by
calling <function>socket_last_error</function>. This error code may be
passed to <function>socket_strerror</function> to get a textual explanation
of the error.
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>socket_recv</function> example</title>
<para>
This example is a simple rewrite of the first example from
<xref linkend="sockets.examples" /> to
use <function>socket_recv</function>.
</para>
<programlisting role="php">
<![CDATA[
<?php
error_reporting(E_ALL);
echo "<h2>TCP/IP Connection</h2>\n";
/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');
/* Get the IP address for the target host. */
$address = gethostbyname('www.example.com');
/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
echo "socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
} else {
echo "OK.\n";
}
echo "Attempting to connect to '$address' on port '$service_port'...";
$result = socket_connect($socket, $address, $service_port);
if ($result === false) {
echo "socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket)) . "\n";
} else {
echo "OK.\n";
}
$in = "HEAD / HTTP/1.1\r\n";
$in .= "Host: www.example.com\r\n";
$in .= "Connection: Close\r\n\r\n";
$out = '';
echo "Sending HTTP HEAD request...";
socket_write($socket, $in, strlen($in));
echo "OK.\n";
echo "Reading response:\n\n";
$buf = 'This is my buffer.';
if (false !== ($bytes = socket_recv($socket, $buf, 2048, MSG_WAITALL))) {
echo "Read $bytes bytes from socket_recv(). Closing socket...";
} else {
echo "socket_recv() failed; reason: " . socket_strerror(socket_last_error($socket)) . "\n";
}
socket_close($socket);
echo $buf . "\n";
echo "OK.\n\n";
?>
]]>
</programlisting>
<para>
The above example will produce something like:
</para>
<screen>
<![CDATA[
<h2>TCP/IP Connection</h2>
OK.
Attempting to connect to '208.77.188.166' on port '80'...OK.
Sending HTTP HEAD request...OK.
Reading response:
Closing socket...HTTP/1.1 200 OK
Date: Mon, 14 Sep 2009 08:56:36 GMT
Server: Apache/2.2.3 (Red Hat)
Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT
ETag: "b80f4-1b6-80bfd280"
Accept-Ranges: bytes
Content-Length: 438
Connection: close
Content-Type: text/html; charset=UTF-8
OK.
]]>
</screen>
</example>
</para>
</refsect1>
</refentry>
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