How to do a 301 redirect from an AWS lambda function

aws-lambda-redirect.js

exports.handler = (event, context, callback) => {
   const response = {
    statusCode: 301,
    headers: {
      Location: 'https://google.com',
    }
  };

  return callback(null, response);
}

Great for:

• Download URLS
• Link shortening tools
• Unauthorized calls
• Rick rolls

Hey David, any insight on how to do it with async/await and not callback

@fwahlqvist here's a simple way to do that:

exports.handler = async (event) => {
    const response = {
        statusCode: 301,
        headers: {
            Location: 'https://google.com'
        }
    };
    
    return response;
};

Thanks for this!

@DavidWells can I redirect to multiple locations?

Any tips for specific URL rules?

Useful! Thank you.

Agreed, very useful.

Thanks so much!

@DavidWells can I redirect to multiple locations?

That's now how HTTP redirects work.

I get the json as HTML in the response, that could be because of the method (GET vs. POST)? Is there any workaround for both methods (GET and POST)?

Right now, I'm just getting the JSON printed on the page instead of performing the redirect itself.

I see there can be many ways. From the official website, I found this: https://docs.aws.amazon.com/amplify/latest/userguide/redirects.html and https://github.com/aws-samples/aws-lambda-redirection-at-edge
For one of our client, I am using the solution mentioned here: https://aws.amazon.com/blogs/networking-and-content-delivery/handling-redirectsedge-part1/ which works pretty well for mass redirects.

@diegopamio, and the following

WARNING:

You have to check the choice of "Use lambda proxy integration" while binding the method to lambda in API gateway, or you will get only JSON.

Following are the snapshot.

When I use this example everything woks locally (Im using SAM CLI), but when I deploy to AWS I keep getting status code 502. Would you know what is the problem? inside cloud watch there is no error

exports.handler = async (event) => {
    const response = {
        statusCode: 301,
        headers: {
            Location: 'https://google.com'
        }
    };
    
    return response;
};

II found the reason, I was adding additional headers. It can't have other headers, only the Location.

How to fix the same issue for httpapi? i get the json printed on the page instead of redirect

Thanks David!!
This helped me a lot!

@diegopamio, and the following

WARNING:

You have to check the choice of "Use lambda proxy integration" while binding the method to lambda in API gateway, or you will get only JSON.

Following are the snapshot.

Further to this -

if you're looking for the docs on why a lambda like this "works", see https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html. Lambdas are not "HTTP enabled" by default, but a key way they can be is through a proxy integration with an API Gateway.

This gist is an example how a lambda can conform to an API Gateway's expectations around proxy integrations.

Those docs describe how the output of a lambda is mapped to an HTTP response
(and also describes how HTTP requests are mapped into the event).

To check if you understand: is the use of callback in the gist necessary?

thank you!

Great for:

• Download URLS
• Link shortening tools
• Unauthorized calls
• Rick rolls

Rick Rolls 😂

Tried out this piece of code, but receiving this error:

{
  "errorType": "Runtime.ImportModuleError",
  "errorMessage": "Error: Cannot find module 'index'\nRequire stack:\n- /var/runtime/index.mjs",
  "trace": [
    "Runtime.ImportModuleError: Error: Cannot find module 'index'",
    "Require stack:",
    "- /var/runtime/index.mjs",
    "    at _loadUserApp (file:///var/runtime/index.mjs:951:17)",
    "    at async Object.UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:976:21)",
    "    at async start (file:///var/runtime/index.mjs:1137:23)",
    "    at async file:///var/runtime/index.mjs:1143:1"
  ]

Anyone else come across this Runtime.ImportModuleError error?

Tried out this piece of code, but receiving this error:

{
  "errorType": "Runtime.ImportModuleError",
  "errorMessage": "Error: Cannot find module 'index'\nRequire stack:\n- /var/runtime/index.mjs",
  "trace": [
    "Runtime.ImportModuleError: Error: Cannot find module 'index'",
    "Require stack:",
    "- /var/runtime/index.mjs",
    "    at _loadUserApp (file:///var/runtime/index.mjs:951:17)",
    "    at async Object.UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:976:21)",
    "    at async start (file:///var/runtime/index.mjs:1137:23)",
    "    at async file:///var/runtime/index.mjs:1143:1"
  ]

Anyone else come across this Runtime.ImportModuleError error?

Can you show the code causing the problem?

Came across this recently. The proper Lambda Edge function should look like:

exports.handler = (event, context, callback) => {
   const response = {
    status: 301,
    headers: {
        location: [{
            key:   'Location', 
            value: 'https://google.com',
        }],
    },
  };
  return callback(null, response);
}

Furthermore, the Role Trust Relationship for your Lambda should include:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Service": [
                    "lambda.amazonaws.com",
                    "edgelambda.amazonaws.com"
                ]
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

Tried out this piece of code, but receiving this error:

{
  "errorType": "Runtime.ImportModuleError",
  "errorMessage": "Error: Cannot find module 'index'\nRequire stack:\n- /var/runtime/index.mjs",
  "trace": [
    "Runtime.ImportModuleError: Error: Cannot find module 'index'",
    "Require stack:",
    "- /var/runtime/index.mjs",
    "    at _loadUserApp (file:///var/runtime/index.mjs:951:17)",
    "    at async Object.UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:976:21)",
    "    at async start (file:///var/runtime/index.mjs:1137:23)",
    "    at async file:///var/runtime/index.mjs:1143:1"
  ]

Anyone else come across this Runtime.ImportModuleError error?

Have you tried naming the js file as 'index.js'?

For those using API Gateway + Lambda, I followed this: https://aws.amazon.com/premiumsupport/knowledge-center/malformed-502-api-gateway/

const response = {
    "statusCode": 200,
    "headers": {
        "my_header": "my_value"
    },
    "body": JSON.stringify(responseBody),
    "isBase64Encoded": false
};

The four fields of statusCode, headers, body, and isBase64Encoded were required