Content-Type header in the wrong place during the response

[mbayou]

• Framework version: 1.5
• Implementations: Spring Boot 2.1.8

Scenario

A Lambda with a GET resource that returns a list of object. Content-Type is application/json; charset=UTF-8.

The lambda is behind an API Gateway. /{proxy+}

Do a GET on the resource and get the list of the object as JSON.

Expected behaviour

Getting the objects with their content as expected.

Actual behaviour

Everything is working fine until we have strings with "special" characters in it, like this one:
"‘’’’"
we are retrieving this: "����"

After investigation and test with another lambda it appears that the header content-type is set in the multiValueHeaders when it should just be in headers

looking at the code of AwsProxyHttpServletResponseWriter it seems like there is no possibility to set the header at the right place.

Thank you for your help

[sapessi]

Hi @mbayou, this is unlikely to be related to the header field - API Gateway reads the multiValueHeaders field in the response just fine. I suspect it may be a bug in the content encoding not using the header value.

By default, we use ISO-8859-1 as the charset. Does it work if you change the default charset in the constructor method of your Lambda handler class:

LambdaContainerHandler.getContainerConfig().setDefaultContentCharset("UTF-8");

[mbayou]

Hi @sapessi ,

Thank you this solution is working perfectly!

However, I do think there is a problem here

I think we should be able from our code to set the normal headers and not only the multiValueHeaders. We have done multiple tests with a small lambda example and if the content-type is not in the normal header it is being ignored.

[sapessi]

It seems to be a bug, but I think the bug is deeper in the stack of this library. I'll leave this open as a bug and dig into it for the next release.

[sapessi]

Release 1.5.1 is making its way to maven central and should be available later today. 🚀