getting error on AWS Cloudformation for Content-Type

Question

I getting error below error in AWS Cloudformation:

Validation Result: warnings : [], errors : [Invalid content type specified: method.response.header.Content-Type] (Service: AmazonApiGateway; Status Code: 400; Error Code: BadRequestException;

rootProxy:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      ResourceId: !Ref rootResource
      RestApiId: !Ref apigatewayRestApi
      AuthorizationType: NONE
      HttpMethod: ANY
      
      RequestParameters:
        method.request.header.Content-Type: false
        method.request.path.proxy: false
        
      Integration:
        PassthroughBehavior: WHEN_NO_MATCH
        RequestParameters:
          integration.request.path.proxy: method.request.path.proxy
          integration.request.header.Content-Type: method.request.header.Content-Type
        IntegrationResponses:
          - 
              StatusCode: 200
              ResponseTemplates: 
                method.response.header.Content-Type: "integration.response.header.Content-Type"
              
            
        Type: AWS
        Credentials: "arn:aws:iam::xxx:user/ali@xxx.com"
        IntegrationHttpMethod: ANY
        Uri: !Sub 
          - arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${SSRlambdaArn}/invocations
          - SSRlambdaArn: !GetAtt SSR.Arn

      MethodResponses:
        -
          StatusCode: 200
          ResponseModels:
            application/json: Empty
            text/plain: Empty
          ResponseParameters:
            method.response.header.Content-Type: true

Any Idea on this error?

Answer 1

For ResponseTemplates you should specify Velocity Template Language code and correct Content-Type for which the template belongs to.

So instead of:

        IntegrationResponses:
          - 
              StatusCode: 200
              ResponseTemplates: 
                method.response.header.Content-Type: "integration.response.header.Content-Type"
              

You should have something like this (just an example; need to modify to your API):

            ResponseTemplates: 
              application/json: |
                  #set($inputRoot = $input.path('$'))
                  [
                  #foreach($elem in $inputRoot)
                    {
                      "number": $elem.id,
                      "class": "$elem.type",
                      "salesPrice": $elem.price 
                    }#if($foreach.hasNext),#end

                  #end
                  ]    

Or maybe you don't need it at all. Its application specific how, and if, to use the ResponseTemplates.