stream_socket_client
Open Internet or Unix domain socket connection
Description
resourcefalse stream_socket_client(
string $address
,
int &$error_code
= null
,
string &$error_message
= null
,
floatnull $timeout
= null
,
int $flags
= STREAM_CLIENT_CONNECT
,
resourcenull $context
= null
)
Note:
The stream will by default be opened in blocking mode. You can
switch it to non-blocking mode by using
stream_set_blocking.
Parameters
-
address
-
Address to the socket to connect to.
-
error_code
-
Will be set to the system level error number if connection fails.
-
error_message
-
Will be set to the system level error message if the connection fails.
-
timeout
-
Number of seconds until the connect()
system call
should timeout. By default, default_socket_timeout
is used.
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, as the
timeout
only applies while making connecting
the socket.
-
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
.
-
context
-
A valid context resource created with stream_context_create.
Return Values
On success a stream resource is returned which may
be used together with the other file functions (such as
fgets, fgetss,
fwrite, fclose, and
feof), false
on failure.
Errors/Exceptions
On failure the error_code
and
error_message
arguments will be populated with the actual
system level error 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. Note that
the error_code
and
error_message
arguments will always be passed by
reference.
Examples
Example #1 stream_socket_client example
<?php
$fp = stream_socket_client("tcp://www.example.com:80", $errno, $errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br />\n";
} else {
fwrite($fp, "GET / HTTP/1.0\r\nHost: www.example.com\r\nAccept: */*\r\n\r\n");
while (!feof($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 - $errstr<br />\n";
} else {
fwrite($fp, "\n");
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.
See List of Supported Socket Transports for a list of built in transports.
See Also
- stream_socket_server
- stream_set_blocking
- stream_set_timeout
- stream_select
- fgets
- fgetss
- fwrite
- fclose
- feof
- cURL Functions