Unable to send xml response with serverless framework - twilio

Question

I'm working with twilio in which when call comes to my twilio number it invokes webhook, I'm using lambda function as webhook,
twilio expects xml(formerly called twiml) response from webhook and i'm unable to send xml response from lambda function
I'm using serverless framework
here is my code
function:
module.exports.voice = (event, context, callback) => {
console.log("event", JSON.stringify(event))
var twiml = new VoiceResponse();
twiml.say({ voice: 'alice' }, 'Hello, What type of podcast would you like to listen? ');
twiml.say({ voice: 'alice' }, 'Please record your response after the beep. Press any key to finish.');
twiml.record({
transcribe: true,
transcribeCallback: '/voice/transcribe',
maxLength: 10
});
console.log("xml: ", twiml.toString())
context.succeed({
body: twiml.toString()
});
};
yml:
service: aws-nodejs
provider:
name: aws
runtime: nodejs6.10
timeout: 10
iamRoleStatements:
- Effect: "Allow"
Action: "*"
Resource: "*"
functions:
voice:
handler: handler.voice
events:
- http:
path: voice
method: post
integration: lambda
response:
headers:
Content-Type: "'application/xml'"
template: $input.path("$")
statusCodes:
200:
pattern: '.*' # JSON response
template:
application/xml: $input.path("$.body") # XML return object
headers:
Content-Type: "'application/xml'"
Response:
please let me know if I'm making some mistake in code
also created an issue on github
Thanks,
Inzamam Malik

Answer 1

You don't need to mess with serverless.yml so much. Here is the simple way:
In serverless.yml...
functions:
voice:
handler: handler.voice
events:
- http:
path: voice
method: post
(response, headers, Content-Type, template, and statusCodes are not necessary)
Then you can just set the statusCode and Content-Type in your function.
So delete this part...
context.succeed({
body: twiml.toString()
});
... and replace it with:
const response = {
statusCode: 200,
headers: {
'Content-Type': 'text/xml',
},
body: twiml.toString(),
};
callback(null, response);
Lambda proxy integration (which is the default) assembles it into a proper response.
Personally I find this way simpler and more readable.

Answer 2

you need your lambda to be a "proxy" type, so you set the body property.
but just try to do
context.succeed(twiml.toString());
that will send the "string" as result directly
or use the callback param:
function(event, context, callback) {
callback(null, twiml.toString())
}

Answer 3

As mentioned by #UXDart, you'll not be able to do this using the standard integration. You should setup a proxy integration with Lambda like here -http://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-create-api-as-simple-proxy-for-lambda.html#api-gateway-proxy-integration-lambda-function-nodejs
This will work better with what you are trying to do, return xml through api gateway.

Answer 4

Change your serverless.yml to this:
service: aws-nodejs
provider:
name: aws
runtime: nodejs6.10
timeout: 10
iamRoleStatements:
- Effect: "Allow"
Action: "*"
Resource: "*"
functions:
voice:
handler: handler.voice
events:
- http:
path: voice
method: post
integration: lambda
response:
headers:
Content-Type: "'application/xml'"
template: $input.path("$")
statusCodes:
200:
pattern: '' # Default response method
template:
# Your script returns json, so match it here
application/json: $input.path("$.body")
headers:
Content-Type: "'application/xml'"

Answer 5

Got mine to work with this.
events:
- http:
path: call/receive
method: post
integration: lambda
response:
headers:
Content-Type: "'application/xml'"
template: $input.path("$")
statusCodes:
200:
pattern: ''
template:
application/json: $input.path("$")
headers:
Content-Type: "'application/xml'"
and
callback(null, twiml.toString());

Answer 6

It works for me.
webhook:
handler: webhook.webhook
events:
- http:
path: webhook
method: get
cors: true
integration: lambda
response:
headers:
Content-Type: "'application/xml'"
template: $input.path("$")
statusCodes:
200:
pattern: '' # Default response method
template:
# Your script returns json, so match it here
application/json: $input.path("$.body")
headers:
Content-Type: "'application/xml'"

Answer 7

Checkout the twilio serverless example here: https://github.com/serverless/examples/tree/master/aws-node-twilio-send-text-message