AWS Lambda function - accessing Path and request parameter value - amazon-web-services

Question

For my POC, created simple lambda function , which will give emp information through rest api.
Created lambda function and access all the emp data using API gateway.
Facing some challenges while accessing particular data.
i am looking for
emp/1 - to retrieve emp id
emp/_search?name="apple" - search name contains apple.
Question is how to retrieve path and request parameters in java code.
public class TestAwsLambdaFunction implements RequestHandler<Map<String, Object>, String> {
#Override
public String handleRequest(Map<String, Object> input, Context context) {
String empID= null;
try {
#SuppressWarnings("unchecked")
Map<String, String> pathParameters = (Map<String, String>) input.get("querystring");
empID= pathParameters.get("id");
System.out.println(empID);
// TO-Do Business logic -
} catch (Exception e) {
// TODO: handle exception
}
return "Hello from Lambda!" + empID;
}
}
What is the best way to expose my data in Rest api call. Bit confused with Lambda or serverless .
have any option to show the data via page wise. Since i am new to AWS. Please guide me

Answer 1

Question is how to retrieve path and request parameters in java code.
You can use mapping template to send $input.params('name') property in the request body to your Lambda function.
What is the best way to expose my data in Rest api call
Use the proxy integration with these guidelines:
Avoid greedy path variables, except perhaps for a catch-all 404.
Avoid using the ANY method.
Define request models and enable request validation (remember it’s off by default).
In your Lambda, check that the content-type header matches one of your request models, and return a 415 Unsupported Media Type status code if it doesn’t (the proxy integration uses the WHEN_NO_MATCH passthrough behavior). After this check, your Lambda can assume the request validation is fully enforced.
By Ben Kehoe
https://read.acloud.guru/how-you-should-and-should-not-use-the-api-gateway-proxy-integration-f9e35479b993
https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-create-api-as-simple-proxy-for-lambda.html#api-gateway-proxy-integration-lambda-function-java
https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-call-api.html
https://github.com/vaquarkhan/Serverless-AWS-Lambda-guide/blob/master/01-aws-lambda-serverless-framework/02-building-rest-api-in-nodejs-with-lambda-gateway.md
https://www.puresec.io/blog/aws-security-best-practices-for-api-gateway
https://www.stackery.io/blog/serverless-function-architecture-principles/
https://technology.finra.org/code/enjoying-auto-scaling-integrated-authentication-low-host-cost.html

Answer 2

You need to choose Lambda Proxy Integrations when you set up your API Gateway. Here's official document Set up Lambda Proxy Integrations in API Gateway.
In this case, API Gateway will pass the whole request data to Lambda, including the request headers, query string parameters, URL path variables and so on. Then you can parse the data using your Java code.