ethers doesn't work in a Worker

[samczsun]

Ethers Version

5.7.2

Search Terms

No response

Describe the Problem

In a Worker, it seems like fetch behaves differently:

const provider = new ethers.providers.JsonRpcProvider('https://rpc.ankr.com/eth');
provider.on('debug', console.log);
provider.on('error', console.log);
await provider.getNetwork();

Uncaught Error: could not detect network (event="noNetwork", code=NETWORK_ERROR, version=providers/5.7.2)
    at Logger.makeError (ethers-5.7.2.umd.min.js:1:62180)
    at Logger.throwError (ethers-5.7.2.umd.min.js:1:62385)
    at JsonRpcProvider.<anonymous> (ethers-5.7.2.umd.min.js:1:655650)
    at step (ethers-5.7.2.umd.min.js:1:642267)
    at Object.throw (ethers-5.7.2.umd.min.js:1:641527)
    at rejected (ethers-5.7.2.umd.min.js:1:640986)

The cause is the following error: Failed to execute 'fetch' on 'WorkerGlobalScope': Referrer 'client' is not a valid URL., which is set here:

ethers.js/packages/web/src.ts/browser-geturl.ts

Line 23 in c80fcdd

request.referrer = "client"; // no-referrer, *client

It seems this was discussed in #1886 but I'm not sure how to turn it on. Given that this affects vanilla JS and not an esoteric platform, maybe the behavior can be changed to be more flexible?

Code Snippet

No response

Contract ABI

No response

Errors

No response

Environment

Browser (Chrome, Safari, etc)

Environment (Other)

No response

[ricmoo]

Instead of passing in the URL directly, try passing in an object that looks like: { skipFetchSetup: true, url }.

That should skip the fetch setup that the affects JavaScriptCore-based systems with a custom/non-standard fetch implementation like Cloudflare Workers… :)

[ricmoo]

(in v6, the fetch class is much more flexible ;))

[samczsun]

I'll give the object a shot! But just to make sure we're on the same page here, I'm referring to a Worker, not a Cloudflare Worker

[ricmoo]

@samczsun Oh, that issue was mainly regarding Cloudflare workers. I’m not sure why a normal Worker would complain about that value for the fetch.

But the object should skip populating it anyways, so may still help you.

[ricmoo]

(also, random question; what browser are you using?)

[samczsun]

Latest Chrome. I think maybe it's because my worker is built from a blob url?

[ricmoo]

Oh. Possibly. I know Safari used to have weird behaviours (especially with things CORS-ish) for BLOB urls.

Did skipFetchSetup work?

[doigensan]

@ricmoo ran into a similar issue this week, provider.getBlockNumber() was returning
missing response (requestBody="{\"method\":\"eth_blockNumber\",\"params\":[],\"id\":42,\"jsonrpc\":\"2.0\"}", requestMethod="POST", serverError={}, url="https://evm-xxx", code=SERVER_ERROR, version=web/5.7.1)

Setting the skipFetchSetup fixed it.
Thank you!

[ricmoo]

Awesome!

I'm going to close this now as fixed. If you have any further issues though, please let me know.

Thanks! :)

[makkarpov]

Global options would be useful. There are libraries that don't allow you to customize everything. I.e. https://github.com/synapsecns/sdk which uses fetchJson and passes just URL there. And while technically it's their fault, I'm afraid that it would be a whack-a-mole game to hunt for every library in the world.