Variables overview
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:
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Make a complex forward path modification
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Select origin based on a pattern
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Read, add, and modify HTTP headers and cookies
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Input to advanced metadata
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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
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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.
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Variable support includes request-stage built-in variables only. For information or assistance with variables form any other stage, contact your account support representative.
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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:
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Construct Response
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Modify Incoming Request Header
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Modify Incoming Response Header
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Modify Outgoing Request Header
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Modify Outgoing Response Header
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Modify Outgoing Request Path
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Origin Base Path
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Origin Server
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Redirect
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Redirect Plus
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Set Response Cookie
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Set Variable
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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}}
Updated over 1 year ago