Function schemeFetch

lib/web/fetch/index.js:813–1007

(fetchParams)

// https://fetch.spec.whatwg.org/#concept-scheme-fetch
// given a fetch params fetchParams
function schemeFetch (fetchParams) {
  // Note: since the connection is destroyed on redirect, which sets fetchParams to a
  // cancelled state, we do not want this condition to trigger *unless* there have been
  // no redirects. See https://github.com/nodejs/undici/issues/1776
  // 1. If fetchParams is canceled, then return the appropriate network error for fetchParams.
  if (isCancelled(fetchParams) && fetchParams.request.redirectCount === 0) {
    return Promise.resolve(makeAppropriateNetworkError(fetchParams))
  }

  // 2. Let request be fetchParams’s request.
  const { request } = fetchParams

  const { protocol: scheme } = requestCurrentURL(request)

  // 3. Switch on request’s current URL’s scheme and run the associated steps:
  switch (scheme) {
    case 'about:': {
      // If request’s current URL’s path is the string "blank", then return a new response
      // whose status message is `OK`, header list is « (`Content-Type`, `text/html;charset=utf-8`) »,
      // and body is the empty byte sequence as a body.

      // Otherwise, return a network error.
      return Promise.resolve(makeNetworkError('about scheme is not supported'))
    }
    case 'blob:': {
      if (!resolveObjectURL) {
        resolveObjectURL = require('node:buffer').resolveObjectURL
      }

      // 1. Let blobURLEntry be request’s current URL’s blob URL entry.
      const blobURLEntry = requestCurrentURL(request)

      // https://github.com/web-platform-tests/wpt/blob/7b0ebaccc62b566a1965396e5be7bb2bc06f841f/FileAPI/url/resources/fetch-tests.js#L52-L56
      // Buffer.resolveObjectURL does not ignore URL queries.
      if (blobURLEntry.search.length !== 0) {
        return Promise.resolve(makeNetworkError('NetworkError when attempting to fetch resource.'))
      }

      const blob = resolveObjectURL(blobURLEntry.toString())

      // 2. If request’s method is not `GET`, blobURLEntry is null, or blobURLEntry’s
      //    object is not a Blob object, then return a network error.
      if (request.method !== 'GET' || !webidl.is.Blob(blob)) {
        return Promise.resolve(makeNetworkError('invalid method'))
      }

      // 3. Let blob be blobURLEntry’s object.
      // Note: done above

      // 4. Let response be a new response.
      const response = makeResponse()

      // 5. Let fullLength be blob’s size.
      const fullLength = blob.size

      // 6. Let serializedFullLength be fullLength, serialized and isomorphic encoded.
      const serializedFullLength = isomorphicEncode(`${fullLength}`)