PHP Manual: Binary-safe file read

Description

stringfalse fread(resource $stream, int $length)

fread reads up to length bytes from the file pointer referenced by stream. Reading stops as soon as one of the following conditions is met:

length bytes have been read
EOF (end of file) is reached
a packet becomes available or the socket timeout occurs (for network streams)
if the stream is read buffered and it does not represent a plain file, at most one read of up to a number of bytes equal to the chunk size (usually 8192) is made; depending on the previously buffered data, the size of the returned data may be larger than the chunk size.

Parameters

stream: A file system pointer resource that is typically created using fopen.
length: Up to length number of bytes read.

Return Values

Returns the read string or false on failure.

Examples

Example #1 A simple fread example

<?php
// get contents of a file into a string
$filename = "/usr/local/something.txt";
$handle = fopen($filename, "r");
$contents = fread($handle, filesize($filename));
fclose($handle);
?>

Example #2 Binary fread example

Warning

On systems which differentiate between binary and text files (i.e. Windows) the file must be opened with 'b' included in fopen mode parameter.

<?php
$filename = "c:\\files\\somepic.gif";
$handle = fopen($filename, "rb");
$contents = fread($handle, filesize($filename));
fclose($handle);
?>

Example #3 Remote fread examples

Warning

When reading from anything that is not a regular local file, such as streams returned when reading remote files or from popen and fsockopen, reading will stop after a packet is available. This means that you should collect the data together in chunks as shown in the examples below.

<?php
$handle = fopen("http://www.example.com/", "rb");
$contents = stream_get_contents($handle);
fclose($handle);
?>

<?php
$handle = fopen("http://www.example.com/", "rb");
if (FALSE === $handle) {
    exit("Failed to open stream to URL");
}

$contents = '';

while (!feof($handle)) {
    $contents .= fread($handle, 8192);
}
fclose($handle);
?>

Notes

Note:
If you just want to get the contents of a file into a string, use file_get_contents as it has much better performance than the code above.

Note:
Note that fread reads from the current position of the file pointer. Use ftell to find the current position of the pointer and rewind to rewind the pointer position.

fread

Description

Parameters

Return Values

Examples

Notes

See Also