Request Header Regex

This capability requires Rules Engine - Advanced Rules which must be purchased separately. Contact your CDN account manager to activate it.

Category: Request

Purpose: Identifies requests by whether they contain a request header whose value matches the pattern defined by a Perl-compatible regular expressionThis type of value is interpreted as a regular expression that defines a pattern of characters..

Key information:

• Header name:
  • Header name comparisons are case-insensitive.
  • Replace spaces in the header name with %20.
  • Only request headers whose name is an exact match to the specified value may satisfy this condition.
• Header value:

  • A value may be defined using any combination of numbers, letters, and/or symbols. This value will be interpreted as a regular expression. Regular expressions are useful for defining a pattern of characters.

    Although regular expressions are quite powerful and can generate flexible solutions, it is strongly recommended that a regular expression statement be constructed, or at the very least proofed, by a developer on your team. This will ensure that the desired behavior will take place.
    
    For example, specifying a ".*" regular expression will match all requests, since the specified pattern matches 0 or more characters. A clearer way to match all requests is through the use of the Always match condition.

  • The case-sensitivity of header value comparisons is determined by the Ignore Case option.
  • Only request headers whose value is an exact match for the specified regular expression may satisfy this condition.
  • Replace spaces in the header value with %20.

• The Result option determines the conditions under which this match condition will be satisfied.

  • Match: Requires the request to contain the specified header and its value must match the regular expression defined in this match condition.

  • Does Not Match: Requires that the request satisfy either of the following criteria:

    • It does not contain the specified header.
    • It contains the specified header, but its value does not match the regular expression defined in this match condition.

• Due to the manner in which cache settings are tracked, this match condition is incompatible with the following features:

  • Default Internal Max-Age
  • Force Internal Max-Age
  • Ignore Origin No-Cache
  • Internal Max-Stale

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