Why fread (PHP) don't read entire file? - php

Question

I have this code on PHP that load a local file:
$filename = "fille.txt";
$fp = fopen($filename, "rb");
$content = fread($fp, 25699);
fclose($fp);
print_r($content);
With this code I can see all the contents of the file. But when I change the $filename to a external link, like:
$filename = "https:/.../texts/fille.txt";
I can't see all the contents of the file, he appears cut to me. Whats the problem?

Answer 1

The fread() function can be used for network operations. But network connections work different than file system operations. A network cannot read a bigger file in a single attempt, that is not how typical networks work. Instead they work package based. So data arrives in chunks.
And if you take a look into the documentation of the function you use then you will see that:
Reading stops as soon as one of the following conditions is met:
[...]
a packet becomes available or the socket timeout occurs (for network streams)
[...]
So what you observe actually is documented behavior. You need to continue to read packages in a loop to get the whole file. Until you received an EOF.
Take a look yourself: https://www.php.net/manual/en/function.fread.php
And further down in that documentation you will see that example:
Example #3 Remote fread() examples
<?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);
?>