My Nginx Conf

nginx.conf

worker_processes 1;

events {
    worker_connections 1024;
}

http {
    # Lua package path and C modules directory
    lua_package_path "/usr/local/share/lua/5.1/?.lua;;";
    lua_package_cpath "/usr/local/lib/lua/5.1/?.so;;";

    proxy_cache_path /tmp/nginx-cache-infura levels=1:2 keys_zone=cache-infura:10m inactive=24h max_size=1g;

    server {
        listen 8080;

        location /mock-api {
            rewrite_by_lua_block {
                ngx.req.read_body()
                local json = require "cjson.safe"

                -- Extract request body data
                local body = ngx.req.get_body_data()
                if not body then
                    ngx.exit(ngx.HTTP_BAD_REQUEST)
                end

                -- Decode request body json
                local data = json.decode(body)
                if not data then
                    ngx.exit(ngx.HTTP_BAD_REQUEST)
                end

                -- Register methods that we want to cache
                local special_methods = {
                    ["eth_getBlockByNumber"] = true,
                }

                -- Register params that we want to cache differently for a method
                local special_params = {
                    ["eth_getBlockByNumber"] = {
                        ["safe"] = true,
                        ["latest"] = true,
                        ["pending"] = true,
                        ["earliest"] = true,
                        ["finalized"] = true,
                    }
                }

                -- Check if the RPC method is meant to be cached
                if data and data.method and data.params and special_methods[data.method] then
                    local method = data.method
                    local block_param = data.params[1]

                    -- Determine if we want to cache differently for methods with special parameters
                    -- Reference: https://docs.infura.io/api/networks/ethereum/json-rpc-methods/eth_getblockbynumber
                    if block_param and special_params[method] and special_params[method][block_param] then
                        ngx.exec("@cached-10s")
                    else
                        ngx.exec("@cached-1h")
                    end
                else
                    ngx.exec("@cached-default")
                end
            }
        }

        location @cached-1h {
            set $path "http://node_service:5000/mock-api/token";
            proxy_cache cache-infura;
            proxy_pass $path;
            proxy_cache_methods POST;
            proxy_cache_key "$scheme$proxy_host$request_uri|$request_body";
            proxy_cache_valid 200 1h;
            add_header X-Cache-Status $upstream_cache_status always;
        }
        
        location @cached-10s {
            set $path "http://node_service:5000/mock-api/token";
            proxy_cache cache-infura;
            proxy_pass $path;
            proxy_cache_methods POST;
            proxy_cache_key "$scheme$proxy_host$request_uri|$request_body";
            proxy_cache_valid 200 10s;
            add_header X-Cache-Status $upstream_cache_status always;
        }

        location @cached-default {
            proxy_pass http://node_service:5000;
        }
    }
}