Feature Request: Allow Uint8 or ObjectURL blobs in deserialize filtered query

[disarticulate]

Was hoping to be able to place flatgeobuf into a webworker and provide range requests/filtered requests from arbitrary serialized geojson features.

However, the range request feature with spatial filter seems directly tied to the HTTP/request system.

Reviewing the code, it looks tightly coupled.

It seems like it should just be given an interface that returns various slices of data from . Is it possible to make a cheap object interface that can be substituted for the <url> input.

[bjornharrtell]

Yeah I agree it would make sense to decouple it.

[disarticulate]

So, I just monkey patched the javascript library's fetch as follows:

//interceptFetch.js
const { fetch: origFetch } = globalThis

globalThis.fetch = async (...args) => {
    const [url, fetchOpts] = args

    for (const [route, handler] of handlers) {
      if (route({ url, fetchOpts })) {
        const response = handler({ url, fetchOpts })
        return response
      }
    }

    return origFetch(...args)

import rangeParser from 'range-parser' // npm package
//handler...
    function appendToUint8Array(arr, data) {
      const newArray = new Uint8Array(arr.length + data.length)
      newArray.set(arr) // copy old data
      newArray.set(data, arr.length) // copy new data after end of old data
      return newArray
    }
   const fcFgb = ...data
    if (fetchOpts?.headers) {
      let chunks
      for (const header of Object.keys(fetchOpts.headers)) {
        if (header.toLowerCase() === 'range') {
          const parser = rangeParser(fcFgb.length, fetchOpts.headers[header])
          chunks = new Uint8Array()
          for (const { start, end } of parser) {
            const chunk = fcFgb.slice(start, end)
            chunks = appendToUint8Array(chunks, chunk)
            console.log('range', { start, end })
          }
        }
      }
      if (chunks) {
        fcFgb = chunks
      }
    }
    return new Response(fcFgb, {
      status: 200,
      headers: {
        'content-type': 'application/vnd.flatgeobuf',
      },
    })