Way to measure request time?

[morley92]

Description

I'm looking to use middleware to measure the request time of openapi-fetch client requests - what's a good way to achieve this? The objects available in openapi-fetch middleware don't appear to include request time.

One approach I've considered is attaching the request start time to the Request object when onRequest is triggered, and then calculating the request time in the onResponse hook e.g.

const myMiddleware: Middleware = {
  async onRequest({ request }) {
    // @ts-ignore
    request.startTime = performance.now();
  },
  async onResponse({ request }) {
    const endTime = performance.now();
    // @ts-ignore
    const latency = endTime - request.startTime;
    console.log(latency);
  },
};

This requires working around the types somewhat though.

Are there any other approaches I could consider?

Proposal

N/A

Extra

• I’m willing to open a PR (see CONTRIBUTING.md)

[duncanbeevers]

You can track flight times outside of the middleware.

I haven't tried this at run-time, but I think a simple Map may do the trick, without affecting any of the middleware signatures.

const requestStartTimes: Map<Request, number> = new Map();
const myMiddleware: Middleware = {
  async onRequest({ request }) {
    requestStartTimes.set(request, performance.now());
  },
  async onResponse({ request }) {
    const startTime = requestStartTimes.get(request);
    requestStartTimes.delete(request);
    const endTime = performance.now();
    const latency = endTime - startTime;
    console.log(latency);
  },
};