Response Transformer

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.