How to parse data in page and return to var using Nginx + Lua

Question

can someone help resolve my issue, i'm using (openresty) nginx + lua, and I need using Lua parse html data between <p> and put parsed value to var

example: <p>Total Cost 100</p> >> $var

Answer 1

You might body_filter_by_lua_block directive, so there should be something like this (didn't test):

location / {
     proxy_pass http://backend;

     body_filter_by_lua_block {
         ngx.arg[1] = ngx.arg[1]:gsub("<p.->(.-)</p>", "%1").
     }
}