PHP
downloads | documentation | faq | getting help | mailing lists | reporting bugs | php.net sites | links | conferences | my php.net

search for in the

socket_recv> <socket_listen
Last updated: Fri, 10 Oct 2008

view this page in

socket_read

(PHP 4 >= 4.0.7, PHP 5)

socket_readReads a maximum of length bytes from a socket

Opis

string socket_read ( resource $socket , int $length [, int $type ] )

The function socket_read() reads from the socket resource socket created by the socket_create() or socket_accept() functions.

Parametry

socket

A valid socket resource created with socket_create() or socket_accept().

length

The maximum number of bytes read is specified by the length parameter. Otherwise you can use \r, \n, or \0 to end reading (depending on the type parameter, see below).

type

Optional type parameter is a named constant:

  • PHP_BINARY_READ (Default) - use the system recv() function. Safe for reading binary data.
  • PHP_NORMAL_READ - reading stops at \n or \r.

Zwracane wartości

socket_read() returns the data as a string on success, or FALSE on error (including if the remote host has closed the connection). The error code can be retrieved with socket_last_error(). This code may be passed to socket_strerror() to get a textual representation of the error.

Informacja: socket_read() returns a zero length string ("") when there is no more data to read.

Rejestr zmian

Wersja Opis
4.1.0 The default value for type was changed from PHP_NORMAL_READ to PHP_BINARY_READ



socket_recv> <socket_listen
Last updated: Fri, 10 Oct 2008
 
add a note add a note User Contributed Notes
socket_read
tech [{at}] swatcash [{dot}] com
02-Jul-2008 01:23
Messed up the end of my previous one. Corrected version here:

a simple work around to non-blocking working with normal read is like so:

$read = array($socket);
$write  = NULL;
$except = NULL;
while(1) {
    $num_changed_sockets = socket_select($read, $write, $except, 0, 1);
    if ( $num_changed_sockets > '0' ) {
        socket_read($socket,10000,PHP_NORMAL_READ);
    }
}
Anonymous
15-Dec-2007 08:11
On non-blocking connections it may not return full length requested.
nad0r1 at hush dot ai
20-Nov-2007 04:59
Another way to bypass the annoying thing with telnet, that send each character as a string ,is to check if the response is "\r\n", that is the string that telnet sends when the user presses enter.

Here is an example:
<?php
error_reporting
(E_ALL);

/* Allow the script to hang around waiting for connections. */
set_time_limit(0);

/* Turn on implicit output flushing so we see what we're getting
 * as it comes in. */
ob_implicit_flush();

$address = '127.0.0.1';
$port = 100;

if ((
$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false) {
    echo
"socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
}

if (
socket_bind($sock, $address, $port) === false) {
    echo
"socket_bind() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
}
else
  echo
'Socket ' . $address . ':' . $port . " has been opened\n";

if (
socket_listen($sock, 5) === false) {
    echo
"socket_listen() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
}
else
   echo
"Listening for new clients..\n";

  
$client_id = 0;
do {
    if ((
$msgsock = socket_accept($sock)) === false) {
        echo
"socket_accept() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
        break;
    }
    else {
       
$client_id += 1;
      echo
"Client #" .$client_id .": Connect\n";
    }
     
   
/* Send instructions. */
   
$msg = "\nWelcome to the PHP Test Server. \n" .
       
"To quit, type 'quit'. To shut down the server type 'shutdown'.\n";
   
socket_write($msgsock, $msg, strlen($msg));
$cur_buf = '';
    do {
        if (
false === ($buf = socket_read($msgsock, 2048))) {
            echo
"socket_read() failed: reason: " . socket_strerror(socket_last_error($msgsock)) . "\n";
            break
2;
        }
        if (
$buf == "\r\n") {
        if (
$cur_buf == 'quit') {
            echo
'Client #' .$client_id .': Disconnect' . "\n";
            break;
        }
        if (
$cur_buf == 'shutdown') {
           
socket_close($msgsock);
            break
2;
        }
       
//else {
      
$talkback = "Unknown command: " . str_replace("\r\n", '\r\n', $cur_buf) ."\n";
      
socket_write($msgsock, $talkback, strlen($talkback));
      
// }
       
echo 'Client #' .$client_id .': ' . $cur_buf . "\n";
       
$cur_buf = '';
        }
        else
$cur_buf .= $buf;
    } while (
true);
   
socket_close($msgsock);
} while (
true);

socket_close($sock);
?>
jgbustos at gmail dot com
17-Jul-2007 02:47
PHP on win32 developers, please look at this bug report before using the PHP_NORMAL_READ option:

http://bugs.php.net/bug.php?id=21197

In a nutshell, using PHP_NORMAL_READ will make your calls to socket_read() return an empty buffer every time.
ein at anti-logic dot com
28-Jun-2007 08:32
the proper way to detect a closed connection is to check socket_last_error.

Connection reset by peer is 104 (either use socket_strerror or don't suppress errors for the time being to find these out), sooo.

while($buffer=@socket_read($sock,512,PHP_NORMAL_READ)){
    echo $buffer;
}
if(socket_last_error($sock) == 104) {
    echo "Connection closed";
}
nuitari-php at nuitari dot net
14-Jun-2007 08:08
PHP_NORMAL_READ - reading stops at \n or \r.

This seems to be meant literally.
If there is a \r, then it will stop reading, even if there is a \n right after it. You have to call the read again just to get rid of the \n.
florin[at nospam]flachi[nospam dot]net
27-Feb-2007 01:22
Hello,

Here is a working solution for using socket_read in nonblocking mode for PHP_NORMAL_MODE read type, as it has some problems in standard PHP.

The function socket_normal_read will read from an unlimited number of sockets in PHP_NORMAL_MODE read type.

If you plan to use this function for an application that uses a lot of sockets that are always opening and closing, you might want to improve it to delete the respective records from $sockets and $queues static variables when you close a socket that you will not use anymore.

<?php

    define
("LINE_END", "\n");

    function
socket_normal_read ($socket, $length) {

        static
$sockets = array ();
        static
$queues = array ();
        static
$sock_num = 0;

        for (
$i = 0;  isset ($sockets[$i]) && $socket != $sockets[$i]; $i++);

        if (!isset (
$sockets[$i])) {
           
$sockets [$sock_num] = $socket;
           
$queues [$sock_num++] = "";
        }

       
$recv = socket_read ($socket, $length, PHP_BINARY_READ);
        if (
$recv === "") {
            if (
strpos ($queues[$i], LINE_END) === false)
                return
false;
        }
        else if (
$recv !== false) {
           
$queues[$i] .= $recv;
        }

       
$pos = strpos ($queues[$i], LINE_END);
        if (
$pos === false)
            return
"";
       
$ret = substr ($queues[$i], 0, $pos);
       
$queues[$i] = substr ($queues[$i], $pos+2);

        return
$ret;
    }

   
$sock1 = socket_create (AF_INET, SOCK_STREAM, SOL_TCP);
   
$sock2 = socket_create (AF_INET, SOCK_STREAM, SOL_TCP);
   
$sock3 = socket_create (AF_INET, SOCK_STREAM, SOL_TCP);
   
$sock4 = socket_create (AF_INET, SOCK_STREAM, SOL_TCP);
   
socket_connect ($sock1, "127.0.0.1", 4551);
   
socket_connect ($sock2, "127.0.0.1", 4552);
   
socket_connect ($sock3, "127.0.0.1", 4553);
   
socket_connect ($sock4, "127.0.0.1", 4554);
   
socket_set_nonblock ($sock1);
   
socket_set_nonblock ($sock2);
   
socket_set_nonblock ($sock3);
   
socket_set_nonblock ($sock4);
    while (
1) {
       
usleep (1000000);
       
$x = socket_normal_read ($sock1, 4096);
        if (
$x !== false && strlen ($x))
            echo
"1: $x\n";
       
$x = socket_normal_read ($sock2, 4096);
        if (
$x !== false && strlen ($x))
            echo
"2: $x\n";
       
$x = socket_normal_read ($sock3, 4096);
        if (
$x !== false && strlen ($x))
            echo
"3: $x\n";
       
$x = socket_normal_read ($sock4, 4096);
        if (
$x !== false && strlen ($x))
            echo
"4: $x\n";
    }

?>

To test this simple application, just use netcat (nc -vv -l 127.0.0.1 455x) to open 4 listening sockets. After you run this script, write some lines in each of those netcat sessions.

I hope this will help people that tried to use test-based socket connections in PHP using the sockets library.

I wait for feedback at the address specified.

Thank you.
dotpointer
05-Feb-2007 12:27
PHP 5.2.0 / Win32 / Apache 1.3 - It seems like...

PHP_BINARY_READ - works, but returns '', not FALSE...
- is blocking, until data received or connection closed
- does pass-through \r\n etc.
- returns data on data, '' on connection closed
- you can detect closed connection by checking for '' (not FALSE as stated i manual)

PHP_NORMAL_READ - not working so good...
- is non-blocking
- does not pass-through \r\n etc.
- returns false on no-data, false on connection closed :(
- (no way here to detect a closed connection...?)
- (is this a bug? http://bugs.php.net/bug.php?id=21880 )
- (is this a bug? http://bugs.php.net/bug.php?id=21197 )
- (could not get data from this option at all in fact...)

PHP_BINARY_READ seems to be the "right way to go"
for now. Both checking for '' and false to detect closed
connection is probably smart, as this "bug"(?) may
be fixed...
Niels laukens
21-Aug-2006 09:34
This paragraph is confusing:

socket_read() returns the data as a string on success, or FALSE on error (including if the remote host has closed the connection). The error code can be retrieved with socket_last_error(). This code may be passed to socket_strerror() to get a textual representation of the error.
Note: socket_read() returns a zero length string ("") when there is no more data to read.

My tests (on PHP 5.1.4) show that when you socket_read() on a shutdown-socket, it returns FALSE when using PHP_NORMAL_READ, but returns "" when reading in PHP_BINARY_READ.
sbasurto at yahoo dot com
11-Aug-2006 08:28
Interesting use of sockets:
<?php
//Use sockets and xml coool!!!
//Check this out
/*
//============================================================
//First you create a xsl template like the following called test.xsl:
<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" encoding="iso-8859-1"/>
<xsl:template match="/">
<table>
<tr><td><font color='red'><xsl:value-of select="test/one"/></font></td></tr>
<tr><td><font color='blue'><xsl:value-of select="test/two"/></font></td></tr>
</table>
</xsl:template>
</xsl:stylesheet>
//============================================================
*/
//============================================================
//Second: You create a php script called getResponse.php with the following content:

echo chr(60).chr(63)."xml version".chr(61)."\"1.0\" encoding".chr(61)."\"ISO".chr(45)."8859".chr(45)."1\" standalone".chr(61)."\"yes\" ".chr(63).chr(62)."\n";
...
connect to a database postgres...
$sql = "select first, second from my_table;";
...
execute the query and asign to $result array...

$xml_string = "<test>\n";
while(
$result){ 
 
$xml_string .= "<one>".$result[0]['first']."</one>\n";
 
$xml_string .= "<two>".$result[0]['second']."</two>\n";
}
$xml_string .= "</test>\n";

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");
header("Content-Type:text/xml");
echo
$xml_string;
//============================================================

//==================S O C K E T S===============================
//Finally: Create a php script called master.php with the following content.
$server = "192.168.0.1"; //my server
$sk = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_connect($sk, $server, 80);
$request = "GET /getResponse.php HTTP/1.0"."\r\n";
$request .= "Host:192.168.0.1 \r\n\r\n";
socket_write($sk, $request);

$doc = new DOMDocument();
$xsl = new XSLTProcessor();
$doc->load("./test.xsl");
$xsl->importStyleSheet($doc);
   
$doc->loadXML(strstr(socket_read($sk,12000),"<?xml"));
echo
$xsl->transformToXML($doc);
//==================S O C K E T S================================

"The output is the result of the query one line red and one blue".

//The most interesting thing here, is that you can create all the
//pages of your site with one xsl template and xml, but with
//the advantage of using the power of PHP.
//cool isn't it?

Regards bazz.
?>
Ronin-php at onabout dot net
02-May-2006 09:06
Just a helper for those trying to use sockets to transfer large ammounts of info.

I was pulling my hair out forever trying to figure out why different strings sent by different socket_writes were getting concatenated by socket_read.

If you have a problem with this, try a sleep(), the delay allows the server to see the difference (it is able to do one before the next arrives)
Bill Kuker
18-Mar-2005 04:31
Just a note that on my system the length seems to have an undocumented upper bound of 65536. I was being lazy and not read()ing in a while loop until I pointed it at real data ;)
michi at tr51 dot org
26-May-2004 09:48
if you'd like to make a "socket_read" on a linux-system connected with a flash-client (v. 6.0 r81) you have to send a string to the connected port:

<?php

  
...  //initialising communication

   
$string = "ready to get/send data\0";
   
socket_write($socket, $string);

   
//now you can read from...
   
$line = trim(socket_read($socket, MAXLINE));

    ... 
// do some stuff, finaly close connection
?>
magicking89 at hotmail dot com
31-Aug-2003 01:01
if you want to use a non block socket you must to use socket_last_error

if(!socket_last_error($sc)){
   if($buffer=socket_read($sc,512,PHP_NORMAL_READ)){
      echo $buffer;
   }
}

if you use it your script wont take all your memory
schst at php-tools dot de
05-Jul-2003 03:19
You may download a generic server class at http://www.php-tools.de
This class will accept the sockets read data from it and hands it to a callback function. Furthermore there are methods for connection handling included.
24-Sep-2002 08:48
Windows telnet sends/recieves one character at a time. Try adding PHP_NORMAL_READ to the end of socket_read, that might help.

socket_recv> <socket_listen
Last updated: Fri, 10 Oct 2008
 
 
show source | credits | sitemap | contact | advertising | mirror sites