Header manipulation

There are a few different policies that offer manipulation of HTTP requests and responses.

The requestHeaderModifier and responseHeaderModifier modify request and response headers respectively. These allow you to add, set, or remove headers. add and set differ in the case the header already exists; set will replace it while add will append.

requestHeaderModifier:
  add:
    x-req-added: value
  remove:
    - x-remove-me

More advanced operations are available with the transformation policy. Like the HeaderModifier policies, this can also add, set, or remove headers, but can also manipulate HTTP bodies. Additionally, each modification is based on a CEL expression rather than static strings.

Examples:

transformations:
  request:
    add:
      x-request-id: 'random()'
  response:
    add:
      x-sub: "jwt.sub"
      x-claim: "jwt.nested.key"
    body: |
      has(jwt.sub) ?
      {"success": "user is authenticated as " + jwt.sub} :
      {"error": "unauthenticated"}      

To modify the request authority (also known as “hostname”) or path, the urlRewrite policy be used:

urlRewrite:
  authority:
    full: example.com
  path:
    full: "/v1/chat/completions"