Why can't I get the length of the iso file with `CURLINFO_CONTENT_LENGTH_DOWNLOAD` in php_curl?
I want to get the length of an iso file on the internet
http://cdimage.debian.org/debian-cd/8.0.0/i386/iso-cd/debian-8.0.0-i386-lxde-CD-1.iso
<?php
$szUrl = 'http://cdimage.debian.org/debian-cd/8.0.0/i386/iso-cd/debian-8.0.0-i386-lxde-CD-1.iso';
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $szUrl);
curl_setopt($curl, CURLOPT_HEADER, 1);
curl_setopt($curl, CURLOPT_NOBODY, 1);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
$size = curl_getinfo($curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD);
echo $size;
?>
The result is -1 with code. How to get iso file length correctly using php_curl?
With Leggendario's answer, the key to my problem is setting CURLOPT_FOLLOWLOCATION to get the correct answer.
This makes my question different from http://stackoverflow.com/questions/2602612/php-remote-file-size-without-downloading-file
.
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From the documentation
CURLINFO_CONTENT_LENGTH_DOWNLOAD
Pass pointer to double to get content length to download. This is the value read from the Content-Length: field. since 7.19.4, this returns -1 if the size is unknown.
You must first execute curl:
curl_exec($curl);
$size = curl_getinfo($curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD);
echo $size;
curl_close($curl);
But be careful because http://cdimage.debian.org/debian-cd/8.0.0/i386/iso-cd/debian-8.0.0-i386-lxde-CD-1.iso is just a redirect to http://gensho.acc.umu.se/debian-cd/8.0.0/i386/iso-cd/debian-8.0.0-i386-lxde-CD-1.iso. You can set the parameter CURLOPT_FOLLOWLOCATION
to true.
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
Otherwise, you will get the size of the redirect page.
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