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.
stream_get_contents
(PHP 5, PHP 7, PHP 8)
stream_get_contents — Reads remainder of a stream into a string
Description
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
length bytes and starting at the specified
offset.
Parameters
-
stream(resource) -
A stream resource (e.g. returned from fopen())
-
length(int) -
The maximum bytes to read. Defaults to
null(read all the remaining buffer). -
offset(int) -
Seek to the specified offset before reading. If this number is negative, no seeking will occur and reading will start from the current position.
Return Values
Returns a string or false on failure.
Changelog
| Version | Description |
|---|---|
| 8.0.0 |
length is now nullable.
|
Examples
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);
}
?>Notes
Note: This function is binary-safe.
Note:
When specifying a
lengthvalue other thannull, this function will immediately allocate an internal buffer of that size even if the actual contents are significantly shorter.
See Also
- fgets() - Gets line from file pointer
- fread() - Binary-safe file read
- fpassthru() - Output all remaining data on a file pointer
add a note
User Contributed Notes 4 notes
vasiliy at hotger dot com ¶
12 years ago
clarck dot smith at gmail dot com ¶
13 years ago
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
m rahman ¶
13 years ago
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.
fearpro13 at gmail dot com ¶
1 year ago
It states that $length parameter which value is null is intended to read all remaining contents from $stream
However, example listed under docs uses -1 as $length parameter to achieve such behavior
Recently i had to start few commands from php7.4 and read content from them, proc_open was used to create processes.
Both output[1] and error[2] pipes were set to non-blocking mode. For some unknown reason sometimes process error[2] channel was available, sometimes not(it was empty string).
After some investigation it was found that stream_get_contents works just great with -1 as a $length value instead of null if you are trying to get all remaining buffer.
