I have tested proxy_cache_key with a single $scheme
proxy_cache_key $scheme; proxy_pass http://127.0.0.1:8081/;
Then I request one to cache.
Then I requested again to confirm the cache
Then I request other url
And hope that it hits cache because the key is $scheme
but it gave me the content of b.html
proxy_cache_key $scheme; does not work?