Request body not coming to app.js file from the aws-serverless-express module

Question

app.js file code :

    app.post('/update/name', function(req, res){
     console.log('Request came  : ', req)  // I printed the whole request no body came
    }

lambda.js (this is the handler function)

    'use strict'
    const awsServerlessExpress = require('aws-serverless-express')
    const app = require('./app')
    const binaryMimeTypes = [
    'application/javascript',
    'application/json',
    'application/octet-stream',
    'application/xml',
    'font/eot',
    'font/opentype',
    'font/otf',
    'image/jpeg',
    'image/png',
    'image/svg+xml',
    'text/comma-separated-values',
    'text/css',
    'text/html',
    'text/javascript',
    'text/plain',
    'text/text',
    'text/xml'
   ]
   const server = awsServerlessExpress.createServer(app, null, 
                    binaryMimeTypes)

   exports.handler = (event, context) => {
    console.log('body came from api gateway', event.body) // here we can see the body in cloudwatch logs
    awsServerlessExpress.proxy(server, event, context) // but when this method makes request to our app.js file where the request goes, no body comes there.
   }

aws-serverless-express (built in node module) code :

  consider this link for the code : 

https://github.com/awslabs/aws-serverless-express/blob/master/index.js

In the aws-serverless-code, I commented this line : https://github.com/awslabs/aws-serverless-express/blob/master/index.js#L36 then I was able to get the body in headers['x-apigateway-event'] that I was reading in app.js, but this is not the correct way as I am touching the modules and when I commit the code in github without node modules, then if another member of my team will pull the code, then he will again not get the body.

Answer 1

I had the same problem. I was trying to invoke my express app endpoint as a Lambda function using aws-serverless-express. All the code was fine, but when I invoked the function with sam local invoke MyFunction -e event.json , I would get an empty req.body . Eventually, thanks to https://github.com/awslabs/aws-serverless-express/issues/92 , I realized that the event file headers was missing Content-Type and did not accept application-json . Adding both to headers solved the problem.

"headers": {
  "Accept": "application/hal+json,text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
  "Content-Type": "application/json;charset=UTF-8"
}

I had used sam local generate-event api to generate the event file.

Answer 2

I tried out the AWS CodeStar template for Web Service with Express.js with Lambda and got the same problem. After some hours of googling and reading the above github thread. I just did the following:

Install body parser:

$ npm install body-parser --save

Then update app.js

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(awsServerlessExpressMiddleware.eventContext());

That should do it