Set Variable

Use the Set Variable policy to set the value of a runtime variable, or to clear a runtime variable, or to add a header variable.

Gateway support

Table 1. Table showing which gateways support this policy, and the corresponding policy version
Gateway	Policy version
DataPower® Gateway (v5 compatible)	1.0.0
DataPower API Gateway, policy available from V2018.4.1.0	2.0.0

This topic describes how to configure the policy in the assembly user interface; for details on how to configure the policy in your OpenAPI source, see set-variable.

About

You can attach this policy to the following API flows:

REST
SOAP

Properties

The following table lists the policy properties, indicates whether a property is required, specifies the valid and default values for input, and specifies the data type of the values.

Table 2. Set Variable policy properties
Property label	Required	Description	Data type
Title	No	The title of the policy. The default value is `set-variable`.	string
Description	No	A description of the policy.	string
Action	Yes	Defines what action to apply on a runtime variable. Choose one of the following values: Set: Indicates that you want to set a runtime variable to a string value. Can be used to set new headers or to override existing values. Add: Indicates that you want to add a header variable. Can be used only to set new headers or to append a new entry of the same header name. Clear: Indicates that you want to delete a runtime variable. Can be used to remove a header when the data is processed in the assembly flow. The default value is Set.	string
Set, Add, or Clear	Yes	Specifies the name of the variable that you want to set , add or clear, depending on the selected Action.	string
Type	Yes	Select the data type of the variable. Choose one of the following values: any string number boolean If you are using the DataPower API Gateway then, for all values other than any, the value is validated against the specified data type.	string
Value	Yes*	Allocates this value to the specified variable. Can be a literal value, or another variable. * Value is required only when `Set` or `Add` is specified as the action. For example, to set a named variable of `billing-hostname` to a literal value, you can specify the Value as `acme.com`. As another example, to set a named variable to the value of the Content-Type header in a request, you can specify the Value entry as `$(request.headers.content-type)`. If the selected value of the Type field is boolean, select the Value check box to indicated a value of `true`. Note: You can only set single string elements. Values are retrieved as strings and therefore you cannot clone a complete nodeset.	string

For examples, see set-variable.