PHP 5.4.33 Released

socket_read

(PHP 4 >= 4.1.0, PHP 5)

socket_readLiest höchstens die angegebene Anzahl Bytes von einem Socket

Beschreibung

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

Die Funktion socket_read() liest von dem Socket socket, der entweder mit socket_create() oder mit socket_accept() erzeugt wurde.

Parameter-Liste

socket

Ein gültiger Socket-Deskriptor, der von socket_create() oder socket_accept() erzeugt wurde.

length

Die Anzahl Bytes, die höchstens gelesen wird, wird in dem Parameter length angegeben. Anderenfalls können Sie mit \r, \n, oder \0 den Lesevorgang beenden (dies ist abhängig von dem Parameter type, siehe weiter unten).

type

Der optionale Parameter type ist eine vordefinierte Konstante:

  • PHP_BINARY_READ (Standardwert) - benutzt die Systemfunktion recv(). Das ist sicher zum Lesen von Binärdaten.
  • PHP_NORMAL_READ - Lesevorgänge werden bei \n oder \r beendet.

Rückgabewerte

socket_read() gibt bei Erfolg die Daten als String zurück oder FALSE, falls ein Fehler aufgetreten ist (oder auch, wenn der entfernte Host die Verbindung abgebrochen hat). Der Fehlercode kann mit socket_last_error() abgefragt werden. Dieser Fehlercode kann an die Funktion socket_strerror() übergeben werden, um eine textuelle Beschreibung des Fehlers zu erhalten.

Hinweis:

socket_read() gibt einen leeren String ("") zurück, wenn es keine Daten mehr zu lesen gibt.

Changelog

Version Beschreibung
4.1.0 Der Vorgabewert für type wurde von PHP_NORMAL_READ auf PHP_BINARY_READ gesetzt.

Siehe auch

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User Contributed Notes 15 notes

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2
t33th4n at gmail dot com
5 years ago
I don't know if is it stated anywhere with this clearance, but here is the source code for detecting the connection abort/closure for sockets testing with socket_read function:

<?php
$buf
= @socket_read($routes[$i][$connectionid]['tunnelsrc'], $buffer_size);
if (
$buf === '')
{
   
$routes[$i][$connectionid]['disconnected']='Conenction abort at source side';
}
?>

($buf === '') is the key :)

I was making an ecrypted tunnel script with mcrypt and was annoying that i could not detect the connection abort from any side.
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1
eng.mrkto.com
3 years ago
It seems like in socket_* functions in BLOCKING mode where is no way to check if more than $length bytes are still available in socket (like stream_get_meta_data()['unread_bytes']).
So you need to choose your prefered maximum $length (like 133693415:) or use non-blocking mode (for realy big data reciving).
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1
Anonymous
6 years ago
On non-blocking connections it may not return full length requested.
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1
nuitari-php at nuitari dot net
7 years ago
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.
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2
michi at tr51 dot org
10 years ago
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
?>
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1
nad0r1 at hush dot ai
6 years ago
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);
?>
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1
Niels laukens
8 years ago
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.
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1
Bill Kuker
9 years ago
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 ;)
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1
magicking89 at hotmail dot com
11 years ago
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
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1
schst at php-tools dot de
11 years ago
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.
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1
Anonymous
11 years ago
Windows telnet sends/recieves one character at a time. Try adding PHP_NORMAL_READ to the end of socket_read, that might help.
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0
tech [{at}] swatcash [{dot}] com
6 years ago
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);
    }
}
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0
dotpointer
7 years ago
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...
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-2
jgbustos at gmail dot com
7 years ago
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.
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-2
ein at anti-logic dot com
7 years ago
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";
}
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