mobiledetect2vcl is a tiny Python script to transform the Mobile Detect JSON database into an UA-based mobile detection VCL subroutine easily integrable in any Varnish Cache configuration.

Usage

1. Execute the script, optionally specifying the location of the JSON database, the name of the VCL subroutine, etc. (use the --help option for additional options):

   $ python mobiledetect2vcl.py > /etc/varnish/mobile_detect.vcl
   

2. Include the generated VCL in your Varnish Cache configuration, calling the mobile detection subroutine during the vcl_recv phase:

   include "mobile_detect.vcl";
   
   ...
   
   sub vcl_recv {
       call mobile_detect;
   
       if (req.http.X-Mobile-Category) {
           std.log("Mobile category: " + req.http.X-Mobile-Category);
           std.log("Mobile type: " + req.http.X-Mobile-Type);
       }
   }
   

3. Use the X-Mobile-Category (e.g. 'phones', 'browsers', 'tablets', 'os' or 'utilities') and X-Mobile-Type (e.g. 'iPhone', 'BlackBerry', 'iPad', etc.) HTTP headers in the req object as you wish. Some ideas:

   • Redirect mobile users to a different location.
   • Normalize the UA header using the device category / type.
   • Forward mobile requests to a specific backend.
   • Cache different versions (i.e. Vary header) of the same URL based on the normalized UAs.

• ...

4. Optionally, you may also consider:
   • Set up periodical updates of the device detection VCL using a simple cron job.
   • Cache the result of the mobile detection subroutine in an user cookie.
   • Include some logic to bypass the mobile detection using some query string parameter.
   • ...

Thanks

A huge thank you to Serban Ghita and all the contributors for maintaining the Mobile Detect database.

Also thanks to other similar projects you may want to consider:

• https://github.com/varnish/varnish-devicedetect
• https://github.com/willemk/varnish-mobiletranslate