vercel/fetch-cached-dns

A decorator on top of `fetch` that caches the DNS query

fetch-cached-dns

This repo has been archived and the source has been moved to vercel/fetch monorepo

A decorator on top of fetch that caches the DNS query of the hostname of the passed URL.

How to use

const fetch = require('@vercel/fetch-cached-dns')(require('node-fetch'))

Since this implementation is implementing redirects we are providing an onRedirect extra option to the fetch call that gets called with the response object and the options that will be used for the next request. This allows to access the request from outside and to modify the options.

NOTE: if the fetch implementation is not supplied, it will attempt to use peerDep node-fetch

fetch-cached-dns's Issues

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Module not fount dns, dgram, ,,,

I get this error when doing follow the guide
const fetch = require('@zeit/fetch-cached-dns')(require('node-fetch'))

Module not found: Can't resolve 'dns' in 'C:\Sony\work\saostar\saostar-fe-pc\node_modules\native-dns-cache'

Support localhost urls

When fetching urls with localhost, we receive errors like this:

Ms-MacBook-Pro:worker arunoda$ npm run testonly -- -t "create jobs"

> @zeit/[email protected] testonly /data/zeit/atlas/worker
> WARN_EXIT=1 jest --coverage -i --verbose --forceExit "-t" "create jobs"

 FAIL  test/worker.js (9.839s)
  ● create jobs

    queryA ENOTFOUND localhost

      at errnoException (dns.js:53:10)
      at QueryReqWrap.onresolve [as oncomplete] (dns.js:241:19)

  ● create jobs (http)

    queryA ENOTFOUND localhost

      at errnoException (dns.js:53:10)
      at QueryReqWrap.onresolve [as oncomplete] (dns.js:241:19)

  ✕ create jobs (5155ms)
  ✕ create jobs (http) (4075ms)
  ○ skipped 21 tests

Test Suites: 1 failed, 7 skipped, 1 of 8 total
Tests:       2 failed, 46 skipped, 48 total
Snapshots:   0 total
Time:        10.748s, estimated 48s

Implement it

1. Parse the URL
2. If the hostname is an IP, go to 4
3. Resolve the hostname to an IP using https://github.com/zeit/dns-cached-resolve
4. Extend the headers supplied (or initialize them if missing) with the hostname
5. Re-construct the URL using the IP instead of the hostname, pass it to the underlying fetch along with the options object from the extended headers from 4

bug: 304 is not redirect and do not include a "Location" header

https://github.com/vercel/fetch-cached-dns/blame/0e278d56fc01f65e83542a9609eadf4ac717bc04/index.js#L8