Dynamic Speed Limiting

Question

Dynamic Speed Limiting

Environment

OnApp CDN

Answer

Note: This feature is not available on the UI, and therefore, kindly contact our support team if you would like to enable it. Dynamic Speed Limiting feature allows customers to restrict the maximum speed based on the specified parameter on the URL, e.g.:

• http://cdn.example.com/testvideo.mp4?speed=1000 - the maximum speed allowed to stream this video is up to 1000B/s

This feature also works along with the existing feature, URL signing, where the speed parameter is required to match with the hash key.

• http://cdn.example.com/testvideo.mp4?speed=1000&secure=SasZXasd - This is the same as above, however, if visitor changing the speed value manually themselves, the video will not able to be viewed.

For generating the harsh key, kindly refer to below for example script in Python:

import hashlib
import string
import base64
import time

# Fill in speed parameter and secret key
secret_key = ''
speed = '1000'
url="/index.html"

# Expiry time
expires_y = 2013
expires_m = 9
expires_d = 29
expires_H = 0
expires_M = 0
expires_S = 0

expires = str(int(time.mktime(time.strptime("%d-%d-%d %d:%d:%d" % (expires_y , expires_m , expires_d , expires_H , expires_M , expires_S) , '%Y-%m-%d %H:%M:%S'))))

def get_hashkey(url , secret_key , expires='', speed=''):
   keystr = "%s%s%s%s" % (expires , url , secret_key, speed)
   #hash_key = md5.new() # for python < 2.5
   hash_key = hashlib.md5()
   hash_key.update(keystr)
   base64_hash_key = base64.encodestring(hash_key.digest()).rstrip('\n').replace('+' , '-').replace('/' , '_')
   return base64_hash_key

# Print the results:
print "Details: '%s' '%s' '%s' '%s'" % (url, secret_key, expires, speed)
print "No Expires : %s " % (get_hashkey(url , secret_key))
print "With Expires :  %s " % (get_hashkey(url , secret_key , expires))
print "No Expires & Speed : %s " % (get_hashkey(url , secret_key, speed=speed))
print "With Expires & Speed :  %s " % (get_hashkey(url , secret_key , expires, speed=speed))