Override fetch function for SQL-over-HTTP

[TimoWilhelm]

Currently the only way to modify the fetch behavior is through the fetchOptions param.

It might also make sense to allow overriding of the fetch function itself. Some SSR frameworks provide alternative fetch functions with additional features or better performance and it could make it easier to extend the fetch behaviour (for example using fetch-retry).

Anyway, the new new SQL-over-HTTP driver looks really promising!

[jawj]

This is a nice idea. I already had vaguely in mind that we should provide something equivalent to the webSocketConstructor option, but for the http case. I'll see to it.

[jawj]

This is released in 0.5.3 and works like this:

import { neonConfig, neon } from '@neondatabase/serverless';

neonConfig.fetchFunction = (url: string, options: any) => {
  console.log('custom fetch:', url, options);
  return fetch(url, options);
};

const sql = neon(process.env.DATABASE_URL);

await sql`SELECT ${"customFetch"} AS str`;

Which logs:

custom fetch: https://ep-xyz.eu-central-1.aws.neon.tech/sql {
  method: 'POST',
  body: '{"query":"SELECT $1 AS str","params":["customFetch"]}',
  headers: {
    'Neon-Connection-String': 'postgres://user:pass@xyz.eu-central-1.aws.neon.tech/main',
    'Neon-Raw-Text-Output': 'true',
    'Neon-Array-Mode': 'true',
    'Neon-Pool-Opt-In': 'true'
  }
}