A large e-commerce furniture company is using a Web application supported by Application Load Balancer. ALB invokes a Lambda function based upon query parameter key within HTTP headers in the client request. When clients search products on this application with size & color options, they get responses only on one of the options & not both. Marketing Team is looking for a quick resolution for this error.
Which of the following can be done to resolve this error?

Answer options:

A.Enable HTTP header condition for Target groups with Target as Lambda function.
B.Enable Path-based routing for Target groups with Target as Lambda function.
C.Enable Host-based routing for Target groups with Target as Lambda function.
D.Enable Multi-Value headers for Target groups with Target as Lambda function.

Correct Answer –D
By default, ALB considers the last value within query parameters while invoking Lambda Function. In the case of multiple query parameters, Multi-value headers need to be enabled to pass all query parameter values to the Lambda function.
Option A is incorrect as this will consider header parameters in the request & not query string parameters.
Option B is incorrect as Path-based routing will consider URL within the request for forwarding towards Target groups.
Option C is incorrect as Host-based routing will consider the host field with HTTP headers for forwarding requests towards Target groups.
For more information on Lambda Function as the target for ALB, refer to the following URL-
https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html#multi-value-headers