output plain text content from Amazon API gateway endpoint

Question

Using Amazon's API Gateway I can create an endpoint that will call a lambda function that outputs plain text. However, when I make a request on the endpoint, the output comes back with the default content type of "application/json". This outputs the plain text response wrapped in quotes. I'd like to change the response header to "text/plain" so it just outputs the text unwrapped with quotes. Does anyone know how to do this?

Answer 1

So I managed to get this working.

In the Integration Response, you need to add a new Mapping Template of type "text/plain"

In the box to enter the template type:

$input.path('$')

Or the path to the value you want to return and save the new Mapping Template (do not select a model!)

You will then need to re-deploy your API for the change to take effect.

One thing I had in place already, was the Method Response also set to "text/plain" using the Empty model. I'm not sure if this has an effect, but if the above doesn't work, just add that in.

Answer 2

Anthony's way still left quotes on the output string. So to recap, on the integration response, create a new Mapping Template for type text/plain. It should have the value:

$input.path('$')

Now, if you run context.succeed("somestring"), the output would be "somestring", wrapped in quotes. This is because, it is stringified as a json term. As a nasty workaround, you may do something like:

var base = JSON.stringify;
JSON.stringify = function(given) {
  JSON.stringify = base;
  return given;
}
context.succeed("somestring");

As a side note, you can get more hints by reading through console.log(context.succeed).