(PHP 5)
stream_get_contents — Reads remainder of a stream into a string
$handle
[, int $maxlength = -1
[, int $offset = -1
]] )
Identical to file_get_contents(), except that
stream_get_contents() operates on an already open
stream resource and returns the remaining contents in a string, up to
maxlength bytes and starting at the specified
offset.
handle (resource)
A stream resource (e.g. returned from fopen())
maxlength (integer)
The maximum bytes to read. Defaults to -1 (read all the remaining buffer).
offset (integer)
Seek to the specified offset before reading. If this number is negative, no seeking will occur and reading will start from the current position.
Returns a string 或者在失败时返回 FALSE.
| 版本 | 说明 |
|---|---|
| 5.1.0 |
The offset was added.
|
Example #1 stream_get_contents() example
<?php
if ($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);
}
?>
Note: 此函数可安全用于二进制对象。
Mathieu (2013-01-09 12:00:51)
When opening large sites/files you may encounter memory problems. I suggest you to use fopen() and fread() for those requests.
Be aware that fopen() in comparison with stream_get_contents() doesn't allow $resource to be null.
<?php
// $resourcemay be empty or a resource (@see stream_context_create()) in my case.
if(!isset($resource) || empty($resource)) {
if(!$handle = fopen($from, 'r', false)) {
exit;
}
}
if(is_resource($resource)) {
if(!$handle = fopen($from, 'r', false, $resource)) {
exit;
}
}
// ... Do something with $handle
?>
vasiliy at hotger dot com (2012-03-22 08:38:00)
It is important to know that stream_get_contents behaves differently with different versions of PHP. Consider the following
<?php
$handle = fopen('file', 'w+'); // truncate + attempt to create
fwrite($handle, '12345'); // file position > 0
rewind($handle); // position = 0
$content = stream_get_contents($handle); // file position = 0 in PHP 5.1.6, file position > 0 in PHP 5.2.17!
fwrite($handle, '6789');
fclose($handle);
/**
*
* 'file' content
*
* PHP 5.1.6:
* 67895
*
* PHP 5.2.17:
* 123456789
*
*/
?>
As a result, stream_get_contents() affects file position in 5.1, and do not affect file position in 5.2 or better.
clarck dot smith at gmail dot com (2011-12-17 19:12:00)
In that case when stream_get_contents/fread/fgets or other stream reading functions block indefinitely your script because they don't reached the limit of bytes to read use the socket_get_meta_data function to figure out the number of the bytes to read. It returns an array that contains a key named 'unread_bytes' and then pass that number to your favourite stream reading functions second parameter to read from the stream.
Maybe a good workaround to use the stream_select function, and set the socket to non-blocking mode with the use of stream_set_blocking($stream, 0). In this case the socket reading functions work properly.
Cheers, Ervin
Anonymous (2011-07-03 17:46:34)
It seems that using fiddler as a proxy in the stream context options causes this function to throw a warning:
Warning: stream_get_contents() [function.stream-get-contents]: SSL: An existing connection was forcibly closed by the remote host.
m rahman (2011-01-20 13:53:32)
When omitting the parameter $maxlength, any received bytes are stacked up until the underlying stream is not readable anymore, the the function returns that stack in one piece.
finalmau at gmail dot com (2008-04-29 16:28:55)
some times this functions cause an max execution time time error, Why?
Simple, if you use it the function wait for have the specified byte length into the resource or the end of file, but, several times this not happend, so we need implement an artificial flag like this:
$tmp = stream_get_contents($this->socket, 42);
while($tmp[42] != 'N'){
//Your code...
$tmp = stream_get_contents($this->socket, 42);
}
Jim Keller (2006-08-28 01:04:52)
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;
}