Understanding Nginx proxy_pass and url path translations

Ref: https://tarunlalwani.com/post/nginx-proxypass-server-paths/

Proxy Pass and Paths

Case #	Nginx location	proxy_pass URL	Test URL	Path received
01	/test01	http://127.0.0.1:8080	/test01/abc/test	/test01/abc/test
02	/test02	http://127.0.0.1:8080/	/test02/abc/test	//abc/test
03	/test03/	http://127.0.0.1:8080	/test03/abc/test	/test03/abc/test
04	/test04/	http://127.0.0.1:8080/	/test04/abc/test	/abc/test
05	/test05	http://127.0.0.1:8080/app1	/test05/abc/test	/app1/abc/test
06	/test06	http://127.0.0.1:8080/app1/	/test06/abc/test	/app1//abc/test
07	/test07/	http://127.0.0.1:8080/app1	/test07/abc/test	/app1abc/test
08	/test08/	http://127.0.0.1:8080/app1/	/test08/abc/test	/app1/abc/test
09	/	http://127.0.0.1:8080	/test09/abc/test	/test09/abc/test
10	/	http://127.0.0.1:8080/	/test10/abc/test	/test10/abc/test
11	/	http://127.0.0.1:8080/app1	/test11/abc/test	/app1test11/abc/test
12	/	http://127.0.0.1:8080/app2/	/test12/abc/test	/app2/test12/abc/test

Run

docker-compose up --build

Output

nginx_1  | Case #   Test URL             $host    $request_uri           $uri
   nx_1  |   01     /test01/abc/test     1.com    /test01/abc/test       /test01/abc/test
             02     /test02/abc/test     2.com    //abc/test             /abc/test
   nx_1  |   03     /test03/abc/test     3.com    /test03/abc/test       /test03/abc/test
             04     /test04/abc/test     4.com    /abc/test              /abc/test
     _1  |   05     /test05/abc/test     5.com    /app1/abc/test         /app1/abc/test
     _1  |   06     /test06/abc/test     6.com    /app1//abc/test        /app1/abc/test
      1  |   07     /test07/abc/test     7.com    /app1abc/test          /app1abc/test
     _1  |   08     /test08/abc/test     8.com    /app1/abc/test         /app1/abc/test
   nx_1  |   09     /test09/abc/test     a.com    /test09/abc/test       /test09/abc/test
   nx_1  |   10     /test10/abc/test     b.com    /test10/abc/test       /test10/abc/test
nginx_1  |   11     /test11/abc/test     c.com    /app1test11/abc/test   /app1test11/abc/test
nginx_1  |   12     /test12/abc/test     d.com    /app2/test12/abc/test  /app2/test12/abc/test