ᛃ epos

Appearance

Fetch ​

epos.fetch() gives you a way to make cross-origin requests.

When normal fetch() fails due to CORS restrictions, epos.fetch() will work.

Why It Exists ​

If your extension runs on a page like example.com and tries to fetch another origin like google.com, the request will fail because of CORS restrictions. This is normal web security behavior.

Extensions can bypass that restriction. If your extension has permission to access google.com, it can make the request. Use epos.fetch() instead of fetch(), and Epos will route the request through the extension.

Which URLs It Can Fetch ​

epos.fetch() can fetch URLs that your project has permission to access.

That access can come from these epos.json fields:

  • matches
  • hostPermissions
  • optionalHostPermissions

If your project does not have permission for a URL, epos.fetch() will fail.

Usage ​

epos.fetch() uses the same API as fetch():

ts
const res = await epos.fetch('https://api.example.com/data')
const data = await res.json()

Limitations ​

epos.fetch() is similar to normal fetch(), but it is not identical.

  • Streaming responses are not supported.
  • Some request parameters are missing.
  • Some response fields and methods are missing.

All supported fields and methods are typed in TypeScript, so your editor can help you avoid unsupported features.