Cruorin is a lightweight extensible cache proxy server.

Cruorin provides an efficient proxy mechanism by throttling concurrent requests in one request window. Also Cruorin exposes necessary hooks to control the proxy flow and cache policy. All hooks only operate simplified object of request and response called IncomingMessage and OutgoingMessage.

Cruorin only proxy and cache GET requests. Cache will be persisted by writing to file and cache key is hash of incoming message URL with host.

npm install --save cruorin

const { Server } = require('cruorin');

class MyServer extends Server {
  reviseRequest(message) {
    // => localhost:9999/?ts=1
    // infer upstream
    message.headers.host = message.headers.host.replace('9999', '8080');
    // remove timestamp
    message.url = message.url.replace(/\??ts=[^&]+&?/, '');
    // <= localhost:8080/
    return message;
  }
}

const server = new MyServer();
server.listen(9999);

Required.
reviseRequest is invoked before transmitting message.
Cruorin will use revised incoming message to emit request and generate internal request hash as cache key.

Optional, default true.
willApplyCache is invoked before reading and writing cache.
true means that responses will be cached permanently.

Optional, default true.
false means that Cruorin will NOT wait for upstream and output a temporary message immediately before upstream responding.

The following table shows QPS of high concurrency simple request in 20 seconds.
The stress test tool is wrk.

(2020/05/29, MacBook Pro 2019)

brew install wrk
npm run play

# 3000 is a fast server
wrk -t 4 -c 300 -d 20 https://localhost:3000

# 3001 is a slow server with 1000ms latency
wrk -t 4 -c 300 -d 20 https://localhost:3001

# 3002 is a crourin server to 3001
wrk -t 4 -c 300 -d 20 https://localhost:3002