Chapter 7[ 163 ]If your application reads request arguments to construct a page, then the $memcached_
key should include these as well:
location / {set $memcached_key "$uri?$args";memcached_pass 127.0.0.1:11211;}If the key is not present, NGINX will need a means of requesting the page from
the application. Hopefully, the application will then write the key/value pair into
memcached so that the next request can be directly served from memory. NGINX
will report a "Not Found" error if the key couldn't be found in memcached, so
the best way to then pass the request to the application is to use the error_page
directive and a location to handle the request. We should also include the error
codes for a "Bad Gateway" error and a "Gateway Timeout" error, in case memcached
does not respond to our key lookup:
server {location / {set $memcached_key "$uri?$args";memcached_pass 127.0.0.1:11211;error_page 404 502 504 = @app;}location @app {proxy_pass 127.0.0.1:8080;}}Remember that by using the equals sign (=) in the arguments to error_page, NGINX
will substitute in the return code from the last argument. This enables us to turn an
error condition into a normal response.