[AWS] API Gateway -> Lambda

Writed: 27 JAN 2020

 

Index

1. Make Lambda Function

2. Create API Gateway

3. Test an API's invoke url

 

1. Make Lambda Function

'use strict';
console.log('Loading hello world function');
 
exports.handler = async (event) => {
    let name = "you";
    let city = 'World';
    let time = 'day';
    let day = '';
    let responseCode = 200;
    console.log("request: " + JSON.stringify(event));
    
    if (event.queryStringParameters && event.queryStringParameters.name) {
        console.log("Received name: " + event.queryStringParameters.name);
        name = event.queryStringParameters.name;
    }
    
    if (event.queryStringParameters && event.queryStringParameters.city) {
        console.log("Received city: " + event.queryStringParameters.city);
        city = event.queryStringParameters.city;
    }
    
    if (event.headers && event.headers['day']) {
        console.log("Received day: " + event.headers.day);
        day = event.headers.day;
    }
    
    if (event.body) {
        let body = JSON.parse(event.body)
        if (body.time) 
            time = body.time;
    }
 
    let greeting = `Good ${time}, ${name} of ${city}.`;
    if (day) greeting += ` Happy ${day}!`;
 
    let responseBody = {
        message: greeting,
        input: event
    };
    
    // The output from a Lambda proxy integration must be 
    // in the following JSON object. The 'headers' property 
    // is for custom response headers in addition to standard 
    // ones. The 'body' property  must be a JSON string. For 
    // base64-encoded payload, you must also set the 'isBase64Encoded'
    // property to 'true'.
    let response = {
        statusCode: responseCode,
        headers: {
            "x-custom-header" : "my custom header value"
        },
        body: JSON.stringify(responseBody)
    };
    console.log("response: " + JSON.stringify(response))
    return response;
};

2. Create API Gateway

1) Create an empty API 

2) Create Resource

3) Create method

 

4) Deploy API

 

5) Note API's invoke API

 

3. Test an API with cURL

1) Download cURL from http://curl.haxx.se/windows 

curl

2) Execute curl.exe with Options(Below URL is exmaple)

 

.\curl.exe -v -X POST "https://r275xc9bmd.execute-api.us-east-1.amazonaws.com/test/helloworld?name=John&city=Seattle" -H "content-type: application/json" -H "day: Thursday"

 

Reference:

https://docs.aws.amazon.com/ko_kr/apigateway/latest/developerguide/api-gateway-create-api-as-simple-proxy-for-lambda.html

https://docs.aws.amazon.com/ko_kr/apigateway/latest/developerguide/api-gateway-create-api-as-simple-proxy-for-lambda.html