fsockopen
(PHP 3, PHP 4 )
fsockopen -- Open Internet or Unix domain socket connection
Description
resource fsockopen ( string target, int port [, int errno
[, string errstr [, float timeout]]])
Initiates a socket connection to the resource specified
by target. PHP supports targets in the Internet and Unix
domains as described in Appendix L. A list of supported
transports can also be retrieved using stream_get_transports().
Note: If you need to set a timeout for reading/writing
data over the socket, use stream_set_timeout(), as the timeout
parameter to fsockopen() only applies while connecting the
socket.
As of PHP 4.3.0, if you have compiled in OpenSSL support,
you may prefix the hostname with either 'ssl://' or 'tls://'
to use an SSL or TLS client connection over TCP/IP to connect
to the remote host.
fsockopen() returns a file pointer which may be used together
with the other file functions (such as fgets(), fgetss(),
fwrite(), fclose(), and feof()).
If the call fails, it will return FALSE and if the optional
errno and errstr arguments are present they will be set
to indicate the actual system level error that occurred
in the system-level connect() call. If the value returned
in errno is 0 and the function returned FALSE, it is an
indication that the error occurred before the connect()
call. This is most likely due to a problem initializing
the socket. Note that the errno and errstr arguments will
always be passed by reference.
Depending on the environment, the Unix domain or the optional
connect timeout may not be available.
The socket will by default be opened in blocking mode.
You can switch it to non-blocking mode by using stream_set_blocking().
Example 1. fsockopen() Example
<?php
$fp = fsockopen("www.example.com", 80, $errno,
$errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br />\n";
} else {
$out = "GET / HTTP/1.1\r\n";
$out .= "Host: www.example.com\r\n";
$out .= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
echo fgets($fp, 128);
}
fclose($fp);
}
?>
The example below shows how to retrieve the day and time
from the UDP service "daytime" (port 13) in your
own machine. Example 2. Using UDP connection
<?php
$fp = fsockopen("udp://127.0.0.1", 13, $errno,
$errstr);
if (!$fp) {
echo "ERROR: $errno - $errstr<br />\n";
} else {
fwrite($fp, "\n");
echo fread($fp, 26);
fclose($fp);
}
?>
Warning
UDP sockets will sometimes appear to have opened without
an error, even if the remote host is unreachable. The error
will only become apparent when you read or write data to/from
the socket. The reason for this is because UDP is a "connectionless"
protocol, which means that the operating system does not
try to establish a link for the socket until it actually
needs to send or receive data.
Note: When specifying a numerical IPv6 address (e.g. fe80::1)
you must enclose the IP in square brackets. For example,
tcp://[fe80::1]:80.
Note: The timeout parameter was introduced in PHP 3.0.9
and UDP support was added in PHP 4.
See also pfsockopen(), stream_set_blocking(), stream_set_timeout(),
fgets(), fgetss(), fwrite(), fclose(), feof(), and the Curl
extension.
