ajax request 'Access Control Allow Origin' - ajax

I am facing a issue of cross origins. I have googled and found some solutions but they are not working in this case. I wonder why.
I am hosting my application in apache tomcat server. And On the application side I am using XMLHttpRequest for request but I am getting "XMLHttpRequest cannot load http://localhost:8888/systeminfo. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' is therefore not allowed access."
Here is the Application js file
function testget()
{
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
alert(xhr.responseText);
}
}
alert('Getting data');
xhr.open('GET', 'http://localhost:8888/systeminfo', true);
xhr.setRequestHeader('Access-Control-Allow-Origin','*');
xhr.setRequestHeader('Access-Control-Allow-Methods','GET');
xhr.send();
}
I am running node js server on local_host:8888 and sending json response when accessed url like 'http://localhost:8888/systeminfo' .
And here is the json response that I am forming and sending from server
function GetSystemInfo(express)
{
express.namespace('/systeminfo', function(){
express.get('/', function(req, res){
var SYSTEM_INFO = 1;
var jsonres = '{\"event\" : [{ \"apiID\" : \"{0}\" }],\"data\":[{ \"manufacturerName\" : \"MNAME\",\"serialNo\" : \"123456\",}] }'.format(SYSTEM_INFO);
res.setHeader('Access-Control-Allow-Origin','*');
res.send(jsonres);
res.end();
});
});
}
Please Help.
Regards,
Techtotie.

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CORS Issue with AWS Lambda and Ajax

So I have been working on this serverless configuration that calls a Lambda function through ajax. The I enable CORs through the API Gateway, and I have made sure of the domain I specified. This domain works when calling other lambda functions within the same API.
Now for the weird stuff.
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Failed to load https://m562ogkc1l.execute-api.us-east-1.amazonaws.com/test/upload: Response to preflight request doesn't pass access control check: The 'Access-Control-Allow-Origin' header has a value 'example.com' that is not equal to the supplied origin. Origin 'http://example.com' is therefore not allowed access.
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Further code is here:
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$('#submitButton').on('click', function(){
//console.log(document.getElementById('fileUpload').value.substring(12));//C:\fakepath\ in front of filename (size = 12)
$.ajax({
type: 'POST',
url: 'https://m562ogkc1l.execute-api.us-east-1.amazonaws.com/test/upload',
data: JSON.stringify({"id": id,"name": document.getElementById('fileUpload').value.substring(12),"body": document.getElementById('fileUpload').files[0]}),
contentType: "application/json",
success: function(data){
console.log(data);
//location.reload();
}
});
return false;
});
Lambda:
const AWS = require('aws-sdk');
var s3 = new AWS.S3();
exports.handler = async (event) => {
let encodedImage = JSON.parse(event.body);
let decodedImage = Buffer.from(encodedImage, 'base64');
var filePath = event.id + '/' + event.name
var params = {
"Body": decodedImage,
"Bucket": "repository.example.com",
"Key": filePath
};
return await new Promise((resolve, reject) => {
s3.upload(params, function(err, data){
if(err) {
let response = {
"statusCode": 200,
"headers": {
"Access-Control-Allow-Origin": "http://example.com"
},
"body": JSON.stringify(err),
"isBase64Encoded": false
};
resolve(response);
} else {
let response = {
"statusCode": 200,
"headers": {
"Access-Control-Allow-Origin": "http://example.com"
},
"body": JSON.stringify(data),
"isBase64Encoded": false
};
resolve(response);
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The following code:
$scope.login = function() {
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$scope.loggingIn = false;
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This is what the OPTIONS request looks like: http://i.stack.imgur.com/FAj96.png
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You might also want to send some params.
var formdata = new FormData();
formdata.append("param_name", "value");
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You just need to change 2 lines from the first code snippet. One would be
xhr.open('POST', '/path_to_page', true); // set to post to send the params
xhr.send(formdata); // send the params
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Which framework are you using??
You can declare base path of your project directory in ajax and the followed by your file.
jQuery.ajax({
type: "GET",
url: "/files/download.mp4",
});
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var io = require('socket.io').listen(80),
fs = require('fs');
io.sockets.on('connection', function (socket) {
socket.on('download', function(req) {
fs.readFile(req.path, function (err, data) {
if (err) throw err;
socket.emit('video', { video: data });
});
});
});
Client:
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
...
// request a download
socket.emit('download', { path: '/files/download.mp4' });
// receive a download
socket.on('video', function (data) {
// do sth with data.video;
});
...
</script>
Edit: didnt notice you didnt want to use sockets. Still it is a viable solution.

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var https = require('https');
var fs = require('fs');
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console.log(req.method);
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req.on('data', function (data) {
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req.on('end', function () {
console.log(body);
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console.log(POST);
});
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res.end("hello, world\n");
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function form_save()
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console.log("submitted!");
var data_obj = {
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$.ajax({
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submitted!
OPTIONS https://adam.testserver.com:9001/ Resource failed to load
jQuery.extend.ajaxjquery.js:3633
$.ajaxjquery.validate.js:1087
form_savew_worksheet.php:64
confirm_deletew_worksheet.php:95
jQuery.event.handlejquery.js:2693
jQuery.event.add.handlejquery.js:2468
w_worksheet.php:73
complete!
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GET". From this point on if I click the button to trigger my AJAX call I get a new error.
submitted!
XMLHttpRequest cannot load https://adam.testserver.com:9001/. Origin
https://adam.testserver.com is not allowed by Access-Control-Allow-Origin.
w_worksheet.php:73
complete!
I don't understand why I get this message as both my form and node server reside on the same server. Thanks for taking the time to read, I appreciate any help I can get on this. I've been stuck for a while now!
You've run into the Cross-Origin Resource Sharing (CORS) specification.
Note the OPTIONS in your output. The OPTIONS HTTP Verb is used by the browser to query the web server about the URL, not to GET its contents or POST data to it.
Your server doesn't respond with the correct header data on a CORS request, so your browser assumes it has no rights to access the data, and refuses to GET or POST to the URL.
If you truly want to let any website in the world run that AJAX request, you can do something similar to the following:
function handleOptions(request, response) {
response.writeHead(200, {
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Method": "POST, GET, OPTIONS",
"Access-Control-Allow-Headers": request.headers["access-control-request-headers"]
});
response.end();
}
function server(request, response) {
if(request.method == "POST") {
handlePost(request, response);
} else if(request.method == "OPTIONS") {
handleOptions(request, response);
} else {
handleOther(response);
}
}
https.createServer(sslObj, server).listen(9001);
You can fill in the details and whether you should handle GET separately, and so on (handleOther should return an appropriate error code for each request method you don't support).

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