Dynamic Variables

Complete reference for dynamic variables available in Edge Rule actions like redirects, header modifications, and origin changes.

Edge Rules support dynamic variables that automatically adapt based on request data. These variables allow you to create flexible rules for redirects, header modifications, and origin changes.

Supported actions

Variable expansion works in the following Edge Rule actions:

• Redirect to URL
• Change Origin URL
• Set Request Header
• Set Response Header

Variable syntax

There are two variable syntaxes available:

Syntax	Format	Example
Basic	{{variable}}	{{path}}
Advanced	%{Collection.Key}	%{User.CountryCode}

The {{ variable }} syntax automatically includes slashes where needed in URLs. When using %{Collection.Key} syntax, you need to manually include slashes in your URLs.

Basic variables

These simple variables are commonly used for general redirection and header logic:

Variable	Description	Example Output
{{path}}	Full request path including query string	/videos/test.mp4?user=1
{{hostname}}	The hostname from the request	test.b-cdn.net
{{country_code}}	Two-letter country code of the user’s IP	US
{{query_string}}	Query string only (without the ?)	user=1
{{request_method}}	HTTP method used	GET, POST
{{file_name}}	Filename from the URL (last part after /)	file.jpg, test.mp4

Example: Redirect preserving path

To redirect all requests from one domain to another while preserving the path:

Setting	Value
Action	Redirect to URL
Redirect URL	https://www.example.com{{path}}
Status Code	301

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Advanced variable collections

The advanced variable system provides detailed access to request data using the %{Collection.Key} syntax.

RequestHeaders

Access headers from the incoming HTTP request.

Example	Result
%{RequestHeaders.Host}	videos.example.com
%{RequestHeaders.User-Agent}	Browser or client info

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Query

Access specific query parameters from the URL.

For a URL like /video.mp4?user=123:

Variable	Result
%{Query.user}	123

Replace KeyName with your actual query parameter name. For example, if your query is ?Myhash=123, use %{Query.Myhash} to get 123.

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Path

Extract specific segments of the URL path. This is useful for complex routing or origin overrides.

For the example path /hello/world/bunny/eat/carrot.jpg:

Variable	Output	Description
%{Path.0}	hello	First segment
%{Path.1}	world	Second segment
%{Path.0-2}	hello/world/bunny	Range from index 0 to 2
%{Path.1-3}	world/bunny/eat	Range from index 1 to 3
%{Path.3-}	eat/carrot.jpg	From index 3 to end
%{Path.1-}	world/bunny/eat/carrot.jpg	From index 1 to end
%{Path.-1}	hello/world	From start up to (but not including) index 1

If the URL includes a query string and the path you extract doesn’t alter the filename, the query string remains intact. For example, with /hello/world/bunny/eat/carrot.jpg?query=something, using %{Path.1-} returns world/bunny/eat/carrot.jpg?query=something.

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Url

Access parsed components of the full URL.

Variable	Description	Example
%{Url.Filename}	Last part of URL (empty for folders)	video.mp4
%{Url.Extension}	File extension	mp4
%{Url.Directory}	Folder path only	/videos/2024/
%{Url.Hostname}	Hostname from request	cdn.mysite.com
%{Url.Path}	Full path and query	/videos/video.mp4?x=1

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User

Information about the user making the request.

Variable	Description	Example
%{User.IP}	End-user IP address	203.0.113.10
%{User.CountryCode}	Country of the request	DE

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Server

Internal information about the server processing the request.

Variable	Description	Example
%{Server.ZoneCode}	Code of the serving zone	NY
%{Server.ID}	Server ID	9482

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Request

Information about the HTTP request.

Variable	Description	Example
%{Request.Method}	HTTP method	GET, POST
%{Request.Path}	Full URL path and query	/videos/video.mp4?x=1
%{Request.QueryString}	Query string only	x=1

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Practical examples

Redirect non-www to www

Redirect all requests from domain.com to www.domain.com while preserving the path:

Setting	Value
Action	Redirect to URL
Redirect URL	https://www.domain.com{{path}}
Status Code	301
Condition	Request URL
Condition Value	*

This rule must be added to the pull zone where domain.com is declared, not where www.domain.com is declared.

If both hostnames are in the same pull zone, narrow the condition to *://domain.com* to only match the non-www version.

Route requests based on path segment

Route requests to different origins based on the first path segment:

Setting	Value
Action	Change Origin URL
Origin URL	https://%{Path.0}.example-backend.com/%{Path.1-}
Condition	Request URL
Condition Value	*/api/*

This would route /api/users/123 to https://api.example-backend.com/users/123.

Add country code to request header

Pass the user’s country to your origin for geo-based logic:

Setting	Value
Action	Set Request Header
Header Name	X-User-Country
Header Value	%{User.CountryCode}
Condition	Request URL
Condition Value	*

Related

• Variable Expansion - Detailed syntax reference for variable collections
• Trigger Path Setup - Configure trigger conditions correctly
• Middleware Scripts - For complex transformations beyond Edge Rules