APIGateway Proxy resource doesn't get path parameter into Lambda - amazon-web-services

Question

I need to create an API endpoint, which will trigger a Lambda function and return an image from an S3 bucket.
Example URL: https://abc.execute-api.eu-west-1.amazonaws.com/dev/xyz/00/01/23911414.jpeg
I created an APIGateway instance manually using the web console and it’s working fine.
And I created the same (I guess) using CloudFormation and it’s not working.
The Lambda gets triggered, but it doesn't get the path parameter in the event.
But I want the Lambda function to get /xyz/00/01/23911414.jpeg as the event['path'].
Here is a part of my CloudFormation Template:
RestApi:
Type: AWS::ApiGateway::RestApi
Properties:
Description: Example API Gateway
EndpointConfiguration:
Types:
- REGIONAL
Name: imaginary-api
ProxyResource:
Type: AWS::ApiGateway::Resource
Properties:
RestApiId: !Ref RestApi
ParentId: !GetAtt
- RestApi
- RootResourceId
PathPart: '{proxy+}'
ProxyResourceANY:
Type: AWS::ApiGateway::Method
Properties:
RestApiId: !Ref RestApi
ResourceId: !Ref ProxyResource
HttpMethod: ANY
AuthorizationType: NONE
MethodResponses:
- StatusCode: 200
Integration:
Type: AWS
IntegrationHttpMethod: POST
Uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${ImaginaryLambda.Arn}/invocations
Credentials: !GetAtt ApiGatewayIamRole.Arn
PassthroughBehavior: WHEN_NO_TEMPLATES
RequestTemplates:
"image/jpeg": ""
"image/jpg": ""
IntegrationResponses:
- StatusCode: 200
RestAPIDeployment:
Type: AWS::ApiGateway::Deployment
DependsOn:
- ProxyResource
Properties:
RestApiId: !Ref RestApi
StageName: dev
ImaginaryInvoke:
Type: AWS::Lambda::Permission
Properties:
Action: lambda:InvokeFunction
FunctionName: !GetAtt ImaginaryLambda.Arn
Principal: apigateway.amazonaws.com
SourceArn: !Sub arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:abc/dev
This is the first time I'm using APIGateway and I might have done something wrong here. Any help would be highly appreciated.
UPDATE:
Adding RequestParameters to the Method won't work either.
RequestParameters:
method.request.path.proxy: true

Answer 1

You have different possible integrations:
aws (requires data mapping)
aws_proxy
mock
http
http_proxy
The AWS integration type requires data mapping to get the required attributes (check https://docs.aws.amazon.com/apigateway/latest/developerguide/request-response-data-mappings.html).
You can use AWS_PROXY to get the complete event (check: https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-input-format) including the path attribute.
You can return binary file (be careful with content length) or return a s3 presigned url (thru a redirection for example).

Answer 2

Let me answer my own question.
I was able to fix this with the following values.
RestApi:
Type: AWS::ApiGateway::RestApi
Properties:
Description: Example API Gateway
BinaryMediaTypes:
- "*/*" # <-- Important
EndpointConfiguration:
Types:
- REGIONAL
Name: imaginary-api
ProxyResourceANY:
Type: AWS::ApiGateway::Method
DependsOn:
ProxyResource
Properties:
RestApiId: !Ref RestApi
ResourceId: !Ref ProxyResource
HttpMethod: ANY
AuthorizationType: NONE
RequestParameters:
method.request.path.proxy: true # <-- Important
MethodResponses:
- StatusCode: 200
Integration:
Type: AWS_PROXY # <-- Important
IntegrationHttpMethod: POST
ContentHandling: CONVERT_TO_TEXT # <-- Important, depends on your code
PassthroughBehavior: WHEN_NO_MATCH
Uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${ImaginaryLambda.Arn}/invocations
Credentials: !GetAtt ApiGatewayIamRole.Arn
Something strange I noticed is, even though the manually created one showed as AWS in the web console, it showed as AWS_PROXY when I exported the stage as a Swagger definition.
Comparing the two Swagger definitions helped me a lot comparing the YAMLs taken out from Export as Swagger + API Gateway Extensions option.