fsockopen
Open Internet or Unix domain socket connection
Description
resourcefalse fsockopen(
string $hostname
,
int $port
= -1,
int &$error_code
= null
,
string &$error_message
= null
,
floatnull $timeout
= null
)
PHP supports targets in the Internet and Unix domains as described in
List of Supported Socket Transports. A list of supported transports can also be
retrieved using stream_get_transports.
The socket will by default be opened in blocking mode. You can
switch it to non-blocking mode by using
stream_set_blocking.
The function stream_socket_client is similar but
provides a richer set of options, including non-blocking connection and the
ability to provide a stream context.
Parameters
-
hostname
-
If OpenSSL support is
installed, 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.
-
port
-
The port number. This can be omitted and skipped with
-1
for transports that do not use ports, such as
unix://
.
-
error_code
-
If provided, holds the system level error number that occurred in the
system-level connect()
call.
If the value returned in error_code
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.
-
error_message
-
The error message as a string.
-
timeout
-
The connection timeout, in seconds. When null
, the
default_socket_timeout php.ini setting is used.
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.
Return Values
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
Errors/Exceptions
Throws E_WARNING
if hostname
is
not a valid domain.
Examples
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);
}
?>
Example #2 Using UDP connection
The example below shows how to retrieve the day and time from the UDP
service "daytime" (port 13) in your own machine.
<?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);
}
?>
Notes
Note:
Depending on the environment, the Unix domain or the optional
connect timeout may not be available.
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
.
See Also
- pfsockopen
- stream_socket_client
- stream_set_blocking
- stream_set_timeout
- fgets
- fgetss
- fwrite
- fclose
- feof
- socket_connect
- The Curl extension