stream_socket_recvfrom

(PHP 5, PHP 7, PHP 8)

stream_socket_recvfrom — Lit des données depuis un socket, connecté ou pas

Description

stream_socket_recvfrom(
    resource $socket,
    int $length,
    int $flags = 0,
    ?string &$address = null
): string|false

stream_socket_recvfrom() accepte les données depuis un socket distant, jusqu'à un total de length octets.

Liste de paramètres

socket

Le socket distant.

length

Le nombre d'octets à recevoir de socket.

flags

La valeur de flags peut être la combinaison des constantes suivantes :

**Valeurs possibles pour `flags`**
`STREAM_OOB`	Traite les données en mode OOB (`out-of-band`).
`STREAM_PEEK`	Lit des données depuis le socket, mais n'utilise pas le buffer. Les prochains appels à fread() ou stream_socket_recvfrom() liront les mêmes données.

address

Si le paramètre address est fourni, il recevra l'adresse du socket distant.

Valeurs de retour

Retourne les données lues, sous forme de chaîne de caractères, ou false si une erreur survient.

Exemples

Exemple #1 Exemple avec stream_socket_recvfrom()

<?php
/* Ouvre un socket sur le port 1234 de localhost */
$server = stream_socket_server('tcp://127.0.0.1:1234');

/* Accepte une connexion */
$socket = stream_socket_accept($server);

/* Lit un paquet (1500 est la taille classique MTU) de données OOB */
echo "Received Out-Of-Band: '" . stream_socket_recvfrom($socket, 1500, STREAM_OOB) . "'\n";

/* Lit les données normales in-band, mais ne modifie rien */
echo "Data: '" . stream_socket_recvfrom($socket, 1500, STREAM_PEEK) . "'\n";

/* Relit le même paquet, mais vide le buffer. */
echo "Data: '" . stream_socket_recvfrom($socket, 1500) . "'\n";

/* Terminaison */
fclose($socket);
fclose($server);
?>

Notes

Note:
Si le message reçu est plus grand que length, les données supplémentaires peuvent être détruites, suivant le type de socket utilisé (par exemple UDP).

Note:
L'appel de stream_socket_recvfrom() sur les flux basés sur le socket, après l'appel de fonctions de flux basé sur un tampon (comme fread() ou stream_get_line()) lit directement les données à partir du socket et évite l'utilisation du tampon avec le flux.

Voir aussi

stream_socket_sendto() - Envoie un message au socket, connecté ou pas
stream_socket_client() - Ouvre une connexion socket Internet ou Unix
stream_socket_server() - Crée un socket serveur Unix ou Internet

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User Contributed Notes 3 notes

down

cweiske at php dot net ¶

14 years ago


Note that stream_socket_recvfrom() bypasses stream wrappers including TLS/SSL. While reading from an encrypted stream with fread() will return decrypted data, using stream_socket_recvfrom() will give you the original encrypted bytes.

down

MagicalTux at php dot net ¶

13 years ago


This method may return a peer address not compatible with stream_socket_sendto() if in ipv6.

The ip returned by recvfrom is not within brackets ([]), and has the port appended, which makes it look like ::1:1234. To cut it properly, use strrpos()

down

raat1979 at gmail dot com ¶

9 years ago


Basically there is currently no real way to determine what the position of the Out of band data is in the tcp/ip stream.

However, it seems that In my current environment (winsock: Windows / PHP 5.3.0) you do not peek beyond the OOB byte unless the buffer is empty
reads do read beyond the OOB data. (I'll check my linux box later)

You should be able to figure out the position of the OOB data by peeking and reading from the regular stream
although it would not be 100% reliable as we do read beyond the OOB data when nothing is in front of it.
depending on the high level protocol it might be possible
to handle the specific "no data in front of out-of-band data" case

<?php
echo "<pre>";
$sockets = stream_socket_pair(STREAM_PF_INET, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);
$reader=$sockets[0];
$writer=$sockets[1];

stream_socket_sendto($writer,"abc");
stream_socket_sendto($writer,"xyZ",STREAM_OOB); // ONLY THE LAST BYTE IS MARKED AS OOB DATA
stream_socket_sendto($writer,"def");

echo "\r\n";
echo "Test 1, Peeking beyond oob when the read buffer becomes empty\r\n";
echo "The data order is 'abcxyZdef'\r\n";
stream_select($r=array($reader), $w=array(), $x=array($reader),5);
echo "has regular:";var_dump(count($r)!==0);
echo "has oobData:";var_dump(count($x)!==0);
echo "<span style='color:blue' >Peek (9) regular:".stream_socket_recvfrom($reader,9,STREAM_PEEK)."</span>\r\n"; 
echo "<span style='color:green'>Peek (1) OobData:".stream_socket_recvfrom($reader,9,STREAM_OOB|STREAM_PEEK)."</span>\r\n"; 
echo "<span style='color:black'>READ (4) regular:".stream_socket_recvfrom($reader,4)."</span>\r\n"; 
echo "<span style='color:blue' >Peek (9) regular:".stream_socket_recvfrom($reader,9,STREAM_PEEK)."</span>\r\n"; 
echo "<span style='color:black'>READ (1) regular:".stream_socket_recvfrom($reader,1)."</span>\r\n"; 
echo "<span style='color:blue' >Peek (9) regular:".stream_socket_recvfrom($reader,9,STREAM_PEEK)."</span>\r\n"; 
// read the OOB data
echo "<span style='color:red'  >READ (9) OobData:".stream_socket_recvfrom($reader,9,STREAM_OOB)."</span>\r\n"; 

echo "<span style='color:blue' >Peek (9) regular:".stream_socket_recvfrom($reader,9,STREAM_PEEK)."</span>\r\n"; 

fclose($sockets[0]);
fclose($sockets[1]);
echo "</pre>";
?>
outputs:
Test 1, Peeking beyond oob when the read buffer becomes empty
The data order is 'abcxyZdef'
has regular:bool(true)
has oobData:bool(true)
Peek (9) regular:abcxy
Peek (1) OobData:Z
READ (4) regular:abcx
Peek (9) regular:y
READ (1) regular:y
Peek (9) regular:def
READ (9) OobData:Z
Peek (9) regular:def

<?php
echo "<pre>";
$sockets = stream_socket_pair(STREAM_PF_INET, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);
$reader=$sockets[0];
$writer=$sockets[1];

stream_socket_sendto($writer,"Z",STREAM_OOB); // ONLY THE LAST BYTE IS MARKED AS OOB DATA
stream_socket_sendto($writer,"abcxydef");

echo "<hr/>";
echo "\r\n";
echo "Test 2, peek if there is nothing in front of the OOB data\r\n";
echo "The data order is 'Zabcxydef'\r\n";
stream_select($r=array($reader), $w=array(), $x=array($reader),5);
echo "has regular:";var_dump(count($r)!==0);
echo "has oobData:";var_dump(count($x)!==0);
echo "<span style='color:blue'>peek (9) regular:".stream_socket_recvfrom($reader,9,STREAM_PEEK)."</span>\r\n"; 
echo "<span style='color:red' >Peek (9) OobData:".stream_socket_recvfrom($reader,9,STREAM_OOB)."</span>\r\n"; 
echo "<span style='color:blue'>peek (9) regular:".stream_socket_recvfrom($reader,9,STREAM_PEEK)."</span>\r\n"; 
echo "</pre>";
?>
Outputs: 
Test 2, peek if there is nothing in front of the OOB data
The data order is 'Zabcxydef'
has regular:bool(true)
has oobData:bool(true)
peek (9) regular:abcxydef
Peek (9) OobData:Z
peek (9) regular:abcxydef

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