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Match Workers subrequests by upstream zone — cf.worker.upstream_zone now supported in Transform Rules

Rules

You can now use the cf.worker.upstream_zone field in Transform Rules to control rule execution based on whether a request originates from Workers, including subrequests issued by Workers in other zones.

Match Workers subrequests by upstream zone in Transform Rules

What's new:

  • cf.worker.upstream_zone is now supported in Transform Rules expressions.
  • Skip or apply logic conditionally when handling Workers subrequests.

For example, to add a header when the subrequest comes from another zone:

Text in Expression Editor (replace myappexample.com with your domain):

(cf.worker.upstream_zone != "" and cf.worker.upstream_zone != "myappexample.com")

Selected operation under Modify request header: Set static

Header name: X-External-Workers-Subrequest

Value: 1

This gives you more granular control in how you handle incoming requests for your zone.

Learn more in the Transform Rules documentation and Rules language fields reference.