How to return HTML code from Lambda function in NodeJS?

Question

I have the following Lambda function. I need to return some custom html when the function is called.

I tried:

    exports.handler = async (event, context, callback) => {   
        const response = {
            statusCode: 200,
            headers: {
                'Content-Type': 'text/html',
            },
            body: String("Hi there !"),
        };
        return response;
    }

But when invoking the function, I'm getting the following error : The Lambda function returned an invalid entry in the headers object: Each header entry in the headers object must be an array. We can't connect to the server for this app or website at this time.

I took the code from AWS blueprint :

Original code from AWS :

What am I doing wrong?

Using your code I deployed one https://v7jcebje7mvvl6qfjnddimlk5q0tfrez.lambda-url.us-east-1.on.aws/ (I will remove this soon), and all seems to work fine. I dont see any error log in the log group either — Woohaik, Jan 08 '23 at 16:28
Thanks for your comment @Woohaik. Does yours work behind a cloudfront distribution? In a client request for example? — Thomas Carlton, Jan 08 '23 at 18:04
As error message saying can you please try like this if it works : `headers: { 'Content-Type': ['text/html'], }` — Himanshu Teotia, Jan 08 '23 at 21:58

score 3 · Accepted Answer · answered Jan 08 '23 at 22:31

You appear to have used the regular AWS Lambda blueprint. Edge Lambda functions are different e.g. the status code is returned in status, not in statusCode.

Based on the documented example:

exports.handler = (event, context, callback) => {
    const response = {
        status: '200',
        statusDescription: 'OK',
        headers: {
            'cache-control': [{
                key: 'Cache-Control',
                value: 'max-age=100'
            }],
            'content-type': [{
                key: 'Content-Type',
                value: 'text/html'
            }]
        },
        body: "some HTML content here",
    };
    callback(null, response);
};

How to return HTML code from Lambda function in NodeJS?

1 Answers1