Returning XML in response from Loopback Remote Method

Question

I am using the Loopback Connector REST (1.9.0) and have a remote method that returns XML:

   Foo.remoteMethod
   (  
      \"getXml\",
      {
         accepts:          


        

Answer 1

I recently ran into this with trying to create a dynamic response for Twilio voice calling in Loopback 3.x. In the model.remoteMethod call, explicitly specify the return type and content type as follows:

model.remoteMethod(
    "voiceResponse", {
        accepts: [{
            arg: 'envelopeId',
            type: 'number',
            required: true
        }],
        http: {
            path: '/speak/:envelopeId',
            "verb": 'post'
        },
        returns: [{
            arg: 'body',
            type: 'file',
            root: true
        }, {
            arg: 'Content-Type',
            type: 'string',
            http: {
                target: 'header'
            }
        }],

    }
)

Have your method return both the xml and the content type via the callback function. Note that the first argument in the callback is to return an error if one exists:

model.voiceResponse = function(messageEnvelopeId, callback) {

    app.models.messageEnvelope.findById(messageEnvelopeId, {
        include: ['messages']
    }).then(function(res) {
        let voiceResponse = new VoiceResponse();
        voiceResponse.say({
                voice: 'woman',
                language: 'en'
            },
            "This is a notification alert from your grow system. " + res.toJSON().messages.message
        )

        callback(null,
            voiceResponse.toString(), // returns xml document as a string
            'text/xml'
        );
    });
}