Allow DownstreamCachePurgeLocation to use Nginx script variables

[jaseclamp]

As defined in this stackoverflow question:

http://stackoverflow.com/questions/28355890/ngx-pagespeed-behind-varnish-how-specify-multiple-or-correct-downstreamcachep/28356567#28356567

Currently ProcessScriptVariables only applies to LoadFromFileXXX but expanding that to also include DownstreamCachePurgeLocation would allow Varnish to pass on to Nginx (via headers) the IP address of which downstream cache routed the traffic and consequently PageSpeed will be able to purge the correct Cache.

Thanks

[franklinwise]

+1

[jeffkaufman]

Could you try the allow-downstream-caching-scripting branch and check that it does what you want?

Installation instructions:

cd
NPS_VERSION=1.9.32.4
git clone git@github.com:pagespeed/ngx_pagespeed.git
cd ngx_pagespeed
git checkout allow-downstream-caching-scripting
wget https://dl.google.com/dl/page-speed/psol/${NPS_VERSION}.tar.gz
tar -xzvf ${NPS_VERSION}.tar.gz  # extracts to psol/

cd
NGINX_VERSION=1.8.0
wget http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz
tar -xvzf nginx-${NGINX_VERSION}.tar.gz
cd nginx-${NGINX_VERSION}/
./configure --add-module=$HOME/ngx_pagespeed
make
sudo make install

This is almost the same as https://developers.google.com/speed/pagespeed/module/build_ngx_pagespeed_from_source , but tweaked to use a git checkout instead of a downloaded release.