API Gateway - Return XML or JSON - amazon-web-services

Question

I have a node API Gateway stack and a Node Lambda. I've been trying to get API gateway to return content-type: application/xml OR application/json depending on the request (returnType=xml or returnType=json).
I have tried adding response models and that didn't work. BinaryTypes didn't work either. I have gotten it to do either application/json OR application/xml but I can't get it to do both. Is what I'm trying to do even possible? or should I create two separate endpoints?
This example always returns application/json.
Here is my lambda:
exports.handler = async function (event, context, callback) {
var format = event.format;
if (!format) {
callback(Error("[BadRequest] missing parameters"));
}
const promise = new Promise(function (resolve, reject) {
https
.get("exampleendpoint.com", (res) => {
let body = "";
res.on("data", (chunk) => {
body += chunk;
});
res.on("end", () => {
var results = JSON.parse(body);
if (format && format.toUpperCase() === "XML") {
var response = {
statusCode: 200,
headers: { "content-type": "application/xml" },
body:
'<?xml version="1.0" encoding="UTF-8"?><result>' +
OBJtoXML(results) +
"</result>",
};
resolve(response);
} else {
var response = {
statusCode: 200,
headers: { "content-type": "application/json" },
body: JSON.stringify(results),
};
resolve(response);
}
});
})
.on("error", (e) => {
var response = {
statusCode: 500,
body: "",
errorMessage: "Error from example.com",
};
resolve(response);
});
});
return promise;
};
Here is my api gateway code:
const epqApi = new gateway.RestApi(this, "restApi", {
restApiName: "resultsApi",
cloudWatchRole: true,
description: "Calls the service for the app",
endpointTypes: [gateway.EndpointType.REGIONAL],
deployOptions: {
stageName: "prod",
loggingLevel: gateway.MethodLoggingLevel.OFF,
dataTraceEnabled: false,
},
});
const epqResource = epqApi.root.addResource("v1");
const epqIntegration: gateway.LambdaIntegration =
new gateway.LambdaIntegration(generatePqsResultFunction, {
proxy: false,
allowTestInvoke: true,
passthroughBehavior: gateway.PassthroughBehavior.NEVER,
contentHandling: gateway.ContentHandling.CONVERT_TO_TEXT,
requestTemplates: {
"application/json": `{
"format":"$input.params(\'format\')"
}`,
},
integrationResponses: [
{
statusCode: "200",
responseParameters: {
"method.response.header.Access-Control-Allow-Origin": "'*'",
},
responseTemplates: {
"application/json": "$input.path('$.body')",
"application/xml": "$input.path('$.body')",
},
},
{
statusCode: "400",
selectionPattern: "^\\[BadRequest\\].*",
responseParameters: {
"method.response.header.Access-Control-Allow-Origin": "'*'",
},
responseTemplates: {
"application/javascript":
"#set($inputRoot = $input.path('$')) {\"errorMessage\" : \"$input.path('$.errorMessage')\"}",
},
},
],
});
epqResource.addMethod("GET", epqIntegration, {
requestParameters: {
//all params need to be in here, even if they are not required
"method.request.querystring.x": false,
"method.request.querystring.y": false,
"method.request.querystring.units": false,
"method.request.querystring.format": false,
"method.request.querystring.wkid": false,
"method.request.querystring.includeDate": false,
},
methodResponses: [
// Successful response from the integration
{
statusCode: "200",
responseParameters: {
"method.response.header.Access-Control-Allow-Origin": true,
},
},
{
statusCode: "400",
responseParameters: {
"method.response.header.Access-Control-Allow-Origin": true,
},
},
],
});
}