Available fields and functions

Filter expressions

A URL rewrite rule filter expression (that is, the expression that defines which incoming requests match the rule) can include the following fields:

• cf.edge.server_ip
• cf.edge.server_port
• cf.edge.client_port
• cf.zone.name
• cf.metal.id
• cf.ray_id
• cf.tls_client_auth.*
• http.cookie
• http.host
• http.referer
• http.request.headers
• http.request.headers.*
• http.request.accepted_languages
• http.request.method
• http.request.timestamp.sec
• http.request.timestamp.msec
• http.request.full_uri
• http.request.uri
• http.request.uri.*
• http.request.version
• raw.http.request.full_uri
• raw.http.request.uri
• raw.http.request.uri.*
• http.user_agent
• http.x_forwarded_for
• ip.src
• ip.src.lat
• ip.src.lon
• ip.src.asnum
• ip.src.city
• ip.src.country
• ip.src.continent
• ip.src.is_in_european_union
• ip.src.subdivision_1_iso_code
• ip.src.subdivision_2_iso_code
• ssl

Refer to Fields for reference information on these fields.

Important

• To obtain the value of an HTTP request header using the http.request.headers field, specify the header name in lowercase. For example, to get the first value of the Accept-Encoding request header in an expression, use: http.request.headers["accept-encoding"][0].

• Use the to_string() function to get the string representation of a non-string value like an Integer value.

For information on the available functions, refer to Functions.

Rewrite expressions

A rewrite expression (that is, the expression that defines the dynamic URL rewrite to perform) can only include the following fields:

• http.request.uri.*
• http.request.headers.*
• http.request.accepted_languages

Refer to the Fields reference for more information on these fields.

The concat(), regex_replace(), and wildcard_replace() functions can appear only once in a rewrite expression.