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stream_get_contents

(PHP 5)

stream_get_contents -- Reads remainder of a stream into a string

Description

string stream_get_contents ( resource handle [, int maxlength [, int offset]] )

Identical to file_get_contents(), except that stream_get_contents() operates on an already open stream resource and returns the remaining contents in a string, up to maxlength bytes and starting at the specified offset.

参数

handle (resource)

A stream resource (e.g. returned from fopen())

maxlength (integer)

The maximum bytes to read. Defaults to -1 (read all the remaining buffer).

offset (integer)

Seek to the specified offset before reading. Added in PHP 5.1.0.

返回值

Returns a string, or FALSE on failure.

范例

例子 1. stream_get_contents() example

<?php

if ($stream = fopen('http://www.example.com', 'r')) {
    // print all the page starting at the offset 10
    echo stream_get_contents($stream, -1, 10);

    fclose($stream);
}


if ($stream = fopen('http://www.example.net', 'r')) {
    // print the first 5 bytes
    echo stream_get_contents($stream, 5);

    fclose($stream);
}

?>

参见

fgets()
fread()
fpassthru()

注: 本函数可安全用于二进制对象。


add a note add a note User Contributed Notes
Jim Keller
28-Aug-2006 04:04
Per wez (at php.net), "the trick is to tell the recipient how big the packet is, so that it can read the correct length."

In my own experience, when using PHP streams to send data bursts, the "max length" parameter seems to act more as an exact length parameter, as the stream will block indefinitely until max length is reached or until the other side fcloses() the stream. The latter is ok unless you need to keep the stream open to continue communication, in which case you have to let the receiving end know how much data to expect, or it will block indefinitely if the max length of data is not sent. You need to pack() and prepend the length of the outgoing data stream in the first 4 bytes of the packet, as follows:

function send_pkt($stream, $my_data)
{

   $len = strlen($my_data);

   $send_data = pack('N', $len) . $my_data; //Pack the length in a network-friendly way, then prepend it to the data.

   $final_len = strlen($send_data);

   if ( fwrite($stream, $send_data) < $final_len ) {
                   //something went wrong, trigger error
   }
}

function recv_pkt($stream)
{

   $packed_len = stream_get_contents($stream, 4); //The first 4 bytes contain our N-packed length
   $hdr = unpack('Nlen', $packed_len);
   $len = $hdr['len'];
   $recvd_data = stream_get_contents($stream, $len);

   return $recvd_data;

}
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