Variables give you more control over your configuration. They provide more flexibility when using existing advanced metadata through the use of input/output variables. Create complex properties without the need to implement advanced metadata.

Variables allow you to:

• Make a complex forward path modification

• Select origin based on a pattern

• Read, add, and modify HTTP headers and cookies

• Input to advanced metadata

• Output from advanced metadata to drive further behaviors

Prerequisites

Variable support is available for certain products. If you don't see variable support listed as an available module for a product, contact your account representative to learn more.

You can use built-in variables right away, but to add a user-defined variable to a behavior, first you need to create one.

Notes and restrictions

• A value has a maximum size limit of 8k per variable. Using advanced metadata, the size limit is 16k. Contact your account support representative for help configuring advanced metadata.

• Variable support includes request-stage built-in variables only. For information or assistance with variables form any other stage, contact your account support representative.

• Variable support does not currently distinguish our parent edge servers from our child edge servers. If you need to distinguish between these types of servers, for instance to implement a different functionality, contact your support representative.

Variable types

There are two types of variables. Built-in variables that are read-only variables that address common information about each request, and user-defined variables that you can create, edit, or otherwise modify.

Behaviors that support variables

Many Property Manager behaviors have fields that support the use of variables – they show the "(variable support)" note under the text field. The following behaviors accept variables:

• Construct Response

• Modify Incoming Request Header

• Modify Incoming Response Header

• Modify Outgoing Request Header

• Modify Outgoing Response Header

• Modify Outgoing Request Path

• Origin Base Path

• Origin Server

• Redirect

• Redirect Plus

• Set Response Cookie

• Set Variable

• Site Failover

Syntax

Use the following syntax in any of the behaviors that allow variable support.

{{variableType.variableName}}

Where variable type is either "built-in" or "user".

The built-in variables correspond to underlying metadata variables, typically prefixed with AK_. For instance,{{builtin.AK_PATH}}corresponds to the %(AK_PATH)metadata variable.

The global user variables are prefixed with PMUSER_ in the underlying metadata, for instance, {{user.PMUSER_FOO}}corresponds to %(PMUSER_FOO)in metadata syntax.

The local user variables you create on an include level are prefixed with PMINC_<includeId> in the underlying metadata, for instance {{user.PMINC_inc_12345}}corresponds to %(user.PMINC_inc_12345) in metadata syntax.

Here is an example variable expression syntax that includes a builtin variable, a fixed string, and a user defined variable:

{{builtin.AK_PATH}}fixedstring{{user.PMUSER_FOO}}