Lambda Simple Event (LSE)

LSE is a tool for easily parsing events sent to Lambda from API Gateway using the proxy integration setting. LSE also formulates syntactically correct responses.

Installation

Use the package manager npm to install LSE.

npm i @mattnick/lambda-simple-event

Usage

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
        return resolve(lse.success(200,{message: "OK"}));
    })
};

//Set Access-Control-Allow-Origin Header, defaults to "*"
const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
        lse.setAllowOriginHeaders('example.com');
        return resolve(lse.success(200,{message: "OK"}));
    })
};

Example: Parsing post requests

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
  
        var body = lse.getAllPostBody();
        /* 
        {
            key1: "value1",
            key2: "value2"
        }
        */

        var key1 = lse.getPostBody('key1');
        // value1

        var key3 = lse.getPostBody('key3');
        // null

        return resolve(lse.success(200,{message: "OK"}));
    })
};

Example: Parsing query string variables

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
  
        var queryString = lse.getAllQueryString();
        /* 
        {
            key1: "value1",
            key2: "value2"
        }
        */

        var key1 = lse.getQueryString('key1');
        // value1

        var key3 = lse.getQueryString('key3');
        // null

        return resolve(lse.success(200,{message: "OK"}));
    })
};

Example: Parsing path parameters

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
  
        var params = lse.getAllPathParameters();
        /* 
        {
            key1: "value1",
            key2: "value2"
        }
        */

        var key1 = lse.getPathParameters('key1');
        // value1

        var key3 = lse.getPathParameters('key3');
        // null

        return resolve(lse.success(200,{message: "OK"}));
    })
};

Example: Parsing Authorizer Context

Returns auth information from custom authorizers

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
  
        var auth = lse.getAuthorizerContext();
        /* 
        {
            userID: 9599,
            clientID: "3E2A9E6684218",
            ...
        }
        */

        return resolve(lse.success(200,{message: "OK"}));
    })
};

Example: Other details

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
		
		//Retrieves API Keys Used by API Gateway 
        var apiKey = lse.getApiKey();
        // Returns: string or null
		
		//Returns the http path for the endpoint, does not include the stage
		var apiPath = lse.getApiPath();
		// /test/hello
		
		//Returns the current stage endpoint has been deployed using.
		var apiStage = lse.getApiStage();
		// /beta
		
		//Returns the http method used to call the endpoint
		var apiMethod = lse.getApiMethod();
		// post
		
		//Returns the ID of the API used
		var apiID = lse.getApiID();
		// a3fc4e

        return resolve(lse.success(200,{message: "OK"}));
    })
};

Example: Generating responses

const LambdaSimpleEvent = require('@mattnick/lambda-simple-event');

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
        var statusCode = 200,
        var body = {
	        message: "Hello World"
        };
        return resolve(lse.success(statusCode, body))
    })
};

exports.handler = async (event) => {
    return new Promise((resolve) => {
        const lse = new LambdaSimpleEvent(event);
        var statusCode = 500,
        var body = {
	        message: "Something went wrong"
        };
        return resolve(lse.error(statusCode, body))
    })
};

License

MIT