URL Part Signature
This type of signature could be used in case of some set of files in one folder, e.g.:
/1/2/31.mp4
/1/2/32.mp4
/1/2/33.mp4
Therefore you could generate signed URL for this part
/1/2/
and concatenate different file name without changing signature. Another case of using URL part signature : file names in one subfolder differ with some suffix , e.g.:
/1/2/3_240p.mp4
/1/2/3_360p.mp4
/1/2/3_480p.mp4
This part
/1/2/3_
could be used for generating signature.
Example of the script for signed URL generation
<?php
# link end of life , 3600 - lifetime in seconds
$expire = time() + 3600;
# file in CDN 1/2/3_720p.mp4
$file_part1 = "1/2/3_";
$file_part2 = "720p.mp4";
$file_part1_len = length($file_part1);
$url = ",end=$expire,len=$file_part1_len/$file_part1";
# You can change speed and buffer setting in the URL, by default settings are taken from account`s settings,
# or from domain`s settings
# http://wiki.ahcdn.com/doku.php?id=ru:feature_default_settings
#$url = ",end=$expire,len=$file_part1_len/speed=300K/buffer=5.0/$file_part1";
$domain = 'cdn.domain.com';
$secret = 'qwerty'; # ask CDN support about it
$key = substr(base64_encode(md5("$secret$url", true)), 0, 22);
$key = str_replace('/', '-', $key);
$fullurl = 'http://' . $domain . '/key=' . $key . $url$file_part2;
# You will get link like
# $fullurl == "http://cdn.domain.com/key=9CVHszhqqsA,end=1374068216,len=6/1/2/3_720p.mp4"
?>
You can specify a list of IPs which will not be checked for URL sign ( ‘keycheck_whitelist’ setting ). Can be set via CDN support.
You can read here about regular URL signatures: URL signature