Use custom fetch(er) for the web client

[arfath-linklet]

Use case

By default the web client uses the global fetch. The idea is to configure the client with a custom fetch(er) that may decorate the fetch function with additional functionality. A use case for this could be -

Using mTLS: Cloudflare Workers can use mTLS with added bindings, the binding exposes a fetch(er) with mTLS pre-configured

Describe the solution you'd like

  const client = createClient({
    // A custom fetcher with decorated functionality, in this case a Cloudflare Worker binding with a fetcher preconfigured with mTLS
    fetcher: cloudflareEnv.MY_CERT.fetch
  })

Additional context

https://developers.cloudflare.com/workers/runtime-apis/bindings/mtls

[slvrtrn]

@arfath-linklet, would you like to contribute to the project and create a PR for it? The implementation is rather trivial:

Add fetch? to

export type WebClickHouseClientConfigOptions =
  BaseClickHouseClientConfigOptions & {
    fetch?: typeof fetch
  }

You'll only need to double-check if the signature is compatible with that cloudflareEnv.MY_CERT.fetch like that right away. Then it just needs to be passed to the WebConnection and used instead of the default one there, if it is defined (see WebImpl in the same config.ts file).

If you have more questions, you can always DM me in the community Slack or comment here.