Amazon Silk Browser does not send a user agent when downloading assets specified in a cache manifest

Saturday, May 31, 2014 - 11:08 pm
By Colin

Here is some header info for a file downloaded by the part of the silk browser that is reading the cache manifest:

Date: May 31 21:41:56
HTTP Code: 200
HTTP Version: HTTP/1.1
Referer: -
Size (in bytes): 16057
User Agent:

This means that if you are trying using the user agent on the server to customize content delivery (say for mobile vs desktop), you will have a hard time doing so. You would have to default to:
No user agent == Silk

On the mobile versions of the chrome and safari browsers, the user agent for application cache downloads is the same as the user agent for normal downloads.

I can’t think of any benefit derived from having a blank user agent just for application cache downloads, so I’m calling this Silk characteristic a bug.

-Colin

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