Cache API throws "Error: Unable to delete cached response."

[bulk88]

I’m getting an undocumented exception being thrown from Cache API, “Error: Unable to delete cached response.” from caches.default.delete(). Docs say Cache · Cloudflare Workers docs

returns a Promise for a Boolean response this is a promise rejection I believe, not a promise resolve with a true/false value. Actual code, only fails on real live runtime, not in Workers Preview Quick Edit. Are the docs wrong for delete() or this is a CF bug?

"use strict";

let v8start;
let routes;

addEventListener('fetch', event => {
  if (!v8start) {
    v8start = Date.now()
  };
  event.respondWith(handleRequest(event.request, event))
})

/**
 * Respond to the request
 * @param {Request} request
 */
async function handleRequest(request, event) {
  var url = new URL(request.url);
  var pathname_callback = url.pathname;
  //console.log(pathname_callback);
  if (pathname_callback === "/routes.json") {
    console.log('inr');
    try {
      return new Promise(async function (resolveCB) {
        updateRoutes(event, resolveCB);
      });
    } catch (e) {
      return new Response(e);
    }

  }
}

async function updateRoutes(event, resolveCB) {
  var resp = fetch('https://httpbin.org/get');
  resp = await resp;
  if (resp.status == 200) {
    resp = resp.text();
    resp = await resp;
    try {
      console.log('del prom ' + await caches.default.delete('http://1.1.1.1/routes.json', {
          ignoreMethod: true
        }));
    } catch (e) {
      resolveCB(new Response(e))
    }
    if (resolveCB) {
      resolveCB(new Response(resp, {
          headers: {
            'content-type': 'application/json',
            'cache-control': 'no-cache, no-store',
            "x-FRM-ORIGIN": 'true',
            'x-v8st': v8start
          }
        }))
    } else {
      resolveCB(new Response('impossible 1'))
    }
  } else {
    if (resolveCB)
      resolveCB(resp);
  }
  return;
}

[Cyb3r-Jak3]

The docs are not wrong.
The error you see is returns a Promise for a Boolean response

My guess is that the error is coming from

@bulk88

  if (pathname_callback === "/routes.json") {
    console.log('inr');
    try {
      return new Promise(async function (resolveCB) {
        updateRoutes(event, resolveCB);
      });
    } catch (e) {
      return new Response(e);
    }

  }

You don’t need to make a new Promise when using an async function.

[bulk88]

FetchEvent handler did not call respondWith() before returning, but initiated some asynchronous task. That task will be canceled and default handling will occur -- the request will be sent unmodified to your origin. Remember that you must call respondWith() *before* the event handler returns, if you don't want default handling. You cannot call it asynchronously later on. If you need to wait for I/O (e.g. a subrequest) before generating a Response, then call respondWith() with a Promise (for the eventual Response) as the argument.

The new Promise basically gets a handle to resolveCB native code from runtime, because I generate the Response() obj at many different places in my code, AND I do extra I/O or extra JS Statements (storing stuff in HS global vars) after delivering a HTTP response to the eyeball. I can’t write the code into a “return new Response(body, {headers: ‘X’:‘yz’});” since that stops execution. If I switch event.respondWith(handleRequest(event.request, event)) to handleRequest(event.request, event), I get the message fetch didn’t call respondWith message.

If I keep respondWith(handleRequest( but remove the generic promise you are talking about, I get

Uncaught (in response) TypeError: Incorrect type for Promise: the Promise did not resolve to 'Response'.

new Promise() seems to be a coding pattern for Workers

event.waitUntil fetch with R2

Hi I’m trying to run a fetch post and save to an R2 bucket AFTER returning a response… // this saves to R2 await doThing() return new Response() // this fires the fetch but does not save to R2 event.waitUntil(doThing()) return new Response() const doThing = () => new Promise((resolve) => { fetch('https://example.com', { method: 'POST', body: JSON.stringify({ foo: bar }), }) .then((res) => res.json()) …

and alot of other posts with Promise.all() etc

This cache API throw is a heavily modded version of my code here

Solution-using HTMLRewriter to extract/scrape, not rewrite

@bulk88: Every time you call .arrayBuffer() you are forcing the entire response body through the HTMLRewriter. Rather than trying to escape this by throwing exceptions, it would be better to stop consuming the body when you are done. Unfortunately, this is easier said than done, but something like the following works: import '@worker-tools/event-target-polyfill'; import 'yet-another-abortcontroller-polyfill'; /** * Consumes a `Response` body while discarding all chunks. * Useful for pulli…

but in the example above, I never had to call cache.delete() before.