Overview

Use the Response Transformer policy to transform response headers before the response is sent to the client. You can add, remove, or modify response headers in your Proxy Endpoint responses.

Prerequisites

You can only apply this policy to your Proxy endpoints and Proxies.

Policy Execution Order

Transformation of response headers runs after the Proxy API is called. This policy runs with the Response Mapper.

Expression Enabled Fields in API Policies

All expression enabled fields take expressions from the SnapLogic Expression Language and the API Policy Manager functions.

Starting in the October 2023 release, the Response Mapper and Response Transformer policies support the request and response functions in the APIM Expression Language. These functions enable you to modify the headers for your Proxy endpoints quickly. When you click to enable the expression dropdown, you can access these functions.

Settings

Parameter Name	Description	Default Value	Example

Parameter Name	Description	Default Value	Example
Label	Required. The name for the API policy.	Response Transformer	ReqTrans-TestShared
When this policy should be applied	An expression enabled field that determines the condition to be fulfilled for the API policy to execute.	True	response.method == “POST”
Headers to Add/Replace	The list of headers to add or replace into the response. If the name or value of an entry in the table is blank, no changes are made.	N/A	N/A
Name	The name for the header to add or replace.	N/A	X-content-type-options
Value	The value for the header. If this field is an expression, it can return a list to simulate the header being repeated multiple times in the original response. If the header in the original response was repeated multiple times, this new value replaces all of the original values. If the original values need to be preserved, this field should be an expression that gets the original value and returns a modified version.	N/A	nosniff
Headers to Remove	The list of headers to remove from the response. The subfield Name functions the same way it does for Headers to Add/Replace.	N/A	x-content-age
Status	Indicates whether the API policy is enabled or disabled.	Enabled	Disabled

Use '-' (dash) instead of '_' (underscore) in header name as '_' is ignored and the header is not captured. '-' is internally transformed to '_' for you to map to the Pipeline parameter. For example, HTTP-ACCEPT instead of HTTP_ACCEPT.

Example

In the following example, multiple headers are replaced with new headers in the response.

Video: Add a Response Transformer Policy to a Proxy

Watch the following video to learn how to add a Response Transformer Policy to a Proxy.