Modify Client Request Header

Category: Headers

Purpose: Each request contains a set of request headersThis type of header describes a client's request for content. that describe it. This feature can either:

• Append or overwrite the value assigned to a request header. If the specified request header does not exist, then this feature will add it to the request.
• Delete a request header from the request.

Requests that are forwarded to an origin server will reflect the changes made by this feature.

One of the following actions can be performed on a request header:

Option	Description	Example
Overwrite	The request header value will be set to the specified value.	Request header value (Client): Value1 Request header value (Rules Engine): Value2 New request header value: Value2
Append	The specified value will be added to end of the existing request header value.	Request header value (Client): Value1 Request header value (Rules Engine): Value2 New request header value: Value1Value2
Delete	Deletes the specified request header.	Request header value (Client): Value1 Modify Client Request Header configuration: Delete the request header in question. Result: The specified request header will not be forwarded to the origin server.

Key information:

• Make sure that the value specified in the Name option is an exact match for the desired request header.

• Case is not taken into account for the purpose of identifying a header.

  For example, any of the following variations of the Cache-Control header name can be used to identify it:

  • cache-control
  • CACHE-CONTROL
  • cachE-Control
• Make sure to only use alphanumeric characters, dashes, or underscores when specifying a header name.
• Deleting a header will prevent it from being forwarded to an origin server by our edge servers.
• Use HTTP variables within the Value option to dynamically construct the request header value. However, you may not use response metadata (e.g., %{resp_ResponseHeader}).

• The following headers are reserved and cannot be modified by this feature:

  • forwarded-for
  • host
  • via
  • warning
  • x-forwarded-for
  • All header names that start with "x-ec" are reserved.

More Information

• Request Format (Request Headers)