5.8. Lab 7 - Complex redirects using njs file map.

1. Start an NGINX docker instance with the complex_redirects app by running the following commands: This places the complex_redirects.conf file and complex_redirects.js files into the running NGINX instance.

   EXAMPLE=complex_redirects
   docker run --rm --name njs_example  -v $(pwd)/conf/$EXAMPLE.conf:/etc/nginx/nginx.conf:ro  -v $(pwd)/njs/$EXAMPLE.js:/etc/nginx/example.js:ro -p 80:80 -p 8090:8090 -d nginx
   

   The nginx.conf will be as follows, when going to the / path it will run the resolv code script.:

   ...
   
   http {
      js_include example.js;
   
      upstream backend {
        server 127.0.0.1:8080;
      }
   
      server {
         listen 80;
   
         location = /version {
             js_content version;
         }
   
         # PROXY
   
         location / {
             auth_request /resolv;
             auth_request_set $route $sent_http_route;
   
             proxy_pass http://backend$route$is_args$args;
         }
   
         location = /resolv {
             internal;
   
             js_content resolv;
         }
      }
      }
   

   The njs code is as follows:

   ...
   
   function resolv(r) {
       try {
           var map = open_db();
           var uri = r.variables.request_uri.split("?")[0];
           var mapped_uri = map[uri];
   
           r.headersOut['Route'] = mapped_uri ? mapped_uri : uri;
           r.return(200);
   
       } catch (e) {
           r.return(500, "resolv: " + e);
       }
    }
   ...
   

2. To check the code is working run the following commands:

   curl http://localhost/CCC?a=1
   200 /CCC?a=1
   
   curl http://localhost:8090/map
   200 {}
   
   curl http://localhost:8090/add -X POST --data '{"from": "/CCC", "to": "/AA"}'
   200
   
   curl http://localhost:8090/add -X POST --data '{"from": "/BBB", "to": "/DD"}'
   200
   
   curl http://localhost/CCC?a=1
   200 /AA?a=1
   
   curl http://localhost/BB?a=1
   200 /BB?a=1
   
   curl http://localhost:8090/map
   200 {"/CCC":"/AA","/BBB":"/DD"}
   
   curl http://localhost:8090/remove -X POST --data '{"from": "/CCC"}'
   200
   
   curl http://localhost:8090/map
   200 {"/BBB":"/DD"}
   
   curl http://localhost/CCC?a=1
   200 /CCC?a=1
   
   docker stop njs_example