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I am having a problem with accessing my response headers under CORS scenario. I am doing a CORS call. So, I configured my API configuration in API Manager to accept CORS requests (that is, CORS is enabled for my REST endpoint).

But when my app (Angular2 app) does a post request it (http.post) does not see the response headers. I checked in Chrome Devtools what the browser is receiving by the remote server and it turned out that all expected response headers are received in the browser. Apparently, Angular does not pass it to my code and I am not able to access the headers. Gunter, suggested me to check for the CORS header

Access-Control-Expose-Headers

My question: Where can I tell WSO2 API Manager to pass pass or set this header when CORS is enabled? I tried in api-manager.xml but I did not see the expected header (in my case the header 'Location') after a restart.

Angular2 's Http.post is not returning headers in the response of a POST method invocation

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user2120188
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1 Answers1

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APIM out-of-the-box supports Access-Control-Allow-Headers but not Access-Control-Expose-Headers.

But you can configure APIM to send that header as well. For that, you create a sequence like below and attach it to your API.

<sequence xmlns="http://ws.apache.org/ns/synapse" name="_cors_request_handler_">
     <property name="Access-Control-Expose-Headers" value="Location"  scope="transport" type="STRING"/>
</sequence>

This doc explains how to engage such a sequence file to a particular API or globally to all APIs.

[Update - 2019]

Now APIM by default has a CORS sequence in sequence directory. You can update that accordingly.

And APIM 3.0 supports Access-Control-Expose-Headers out of the box.

Bee
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  • Bhathiya, Thanks a lot! Your feedback helped me alot! I have created a sequence (in the same analogy of your post), tested it and it worked! Apparently, Angular2's Http client is checking actively on this CORS header. Since, I have many Angular2 apps which connects through Http client (@angular2/http) to my API Gateway, I will need to configure APIM to handle the setting of this header (whether by default, manually and globally. I will dig into the docs to read more about customization through mediation. Thanks! – user2120188 Nov 10 '16 at 11:10