STREAM_SOCKET_CLIENT(3) 1 STREAM_SOCKET_CLIENT(3)
stream_socket_client - Open Internet or Unix domain socket connection
SYNOPSIS
resource stream_socket_client (string $remote_socket, [int &$errno], [string &$errstr], [float $timeout = ini_get("default_socket_time-
out")], [int $flags = STREAM_CLIENT_CONNECT], [resource $context])
DESCRIPTION
Initiates a stream or datagram connection to the destination specified by $remote_socket. The type of socket created is determined by the
transport specified using standard URL formatting: transport://target. For Internet Domain sockets (AF_INET) such as TCP and UDP, the tar-
get portion of the $remote_socket parameter should consist of a hostname or IP address followed by a colon and a port number. For Unix
domain sockets, the $target portion should point to the socket file on the filesystem.
Note
The stream will by default be opened in blocking mode. You can switch it to non-blocking mode by using stream_set_blocking(3).
PARAMETERS
o $remote_socket
- Address to the socket to connect to.
o $errno
- Will be set to the system level error number if connection fails.
o $errstr
- Will be set to the system level error message if the connection fails.
o $timeout
- Number of seconds until the connect() system call should timeout.
Note
This parameter only applies when not making asynchronous connection attempts.
Note
To set a timeout for reading/writing data over the socket, use the stream_set_timeout(3), as the $timeout only applies while
making connecting the socket.
o $flags
- Bitmask field which may be set to any combination of connection flags. Currently the select of connection flags is limited to
STREAM_CLIENT_CONNECT (default), STREAM_CLIENT_ASYNC_CONNECT and STREAM_CLIENT_PERSISTENT.
o $context
- A valid context resource created with stream_context_create(3).
RETURN VALUES
On success a stream resource is returned which may be used together with the other file functions (such as fgets(3), fgetss(3), fwrite(3),
fclose(3), and feof(3)), FALSE on failure.
ERRORS
/EXCEPTIONS
On failure the $errno and $errstr arguments will be populated with the actual system level error that occurred in the system-level con-
nect() 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.
EXAMPLES
Example #1
stream_socket_client(3) example
<?php
$fp = stream_socket_client("tcp://www.example.com:80", $errno, $errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br />
";
} else {
fwrite($fp, "GET / HTTP/1.0
Host: www.example.com
Accept: */*
");
while (!feof($fp)) {
echo fgets($fp, 1024);
}
fclose($fp);
}
?>
Example #2
Using UDP connection
Retrieving the day and time from the UDP service "daytime" (port 13) on localhost.
<?php
$fp = stream_socket_client("udp://127.0.0.1:13", $errno, $errstr);
if (!$fp) {
echo "ERROR: $errno - $errstr<br />
";
} else {
fwrite($fp, "
");
echo fread($fp, 26);
fclose($fp);
}
?>
NOTES
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
Depending on the environment, the Unix domain or the optional connect timeout may not be available. A list of available transports
can be retrieved using stream_get_transports(3). See "List of Supported Socket Transports" for a list of built in transports.
SEE ALSO
stream_socket_server(3), stream_set_blocking(3), stream_set_timeout(3), stream_select(3), fgets(3), fgetss(3), fwrite(3), fclose(3),
feof(3), "cURL Functions".
PHP Documentation Group STREAM_SOCKET_CLIENT(3)