Upload File problem - Uncaught Object - PUT http://localhost:8000/undefined

I’m trying to upload a photo taken from the smartphone’s but it does not work in any way…
This is the code that I’m using:

 var byteArray = new Blob([params.photo]);
 var photoName = 'test.jpg';
 var savedFile = Backendless.Files.saveFile("/comment/photo", photoName, byteArray, true);

Where params.photo is the the photo taken from the camera

Error Log:

backendless.js:3477 Uncaught Object {message: "", statusCode: 0}sendEncoded @ backendless.js:3477
backendless.js:3468 PUT http://localhost:8000/undefined 404 (Not Found)sendEncoded @ backendless.js:3468

Any idea how to fix?
I tried even the Backendless.Files.upload but with the same result.
Thanks in advance

Hi Michele,

Where does “localhost:8000” come from? We do not have it anywhere in our code.


Thanks for your reply. I was trying in the browser emulator

Now I tried on an Android smartphone and this is the LOG:

backendless.js:3477 Uncaught Object {message: "", statusCode: 0}sendEncoded @ backendless.js:3477
backendless.js:3468 PUT file:///android_asset/www/undefined net::ERR_FILE_NOT_FOUNDsendEncoded @ backendless.js:3468

is your backend in the Backendless Cloud?


Why? I thinks is a local error and not remote

When you use the api to save a file (that is “Backendless.Files.saveFile”), our library communicates with api.backendless.com. There is something in your code that overrides that and forces the code to send requests locally. Got any ideas?

No. I don’t have any part of code that override the HTTP request…

I just checked your code and the problem is that “this.uploadPath” on #3387 is undefined

Here’s the latest code:

What line of code is it there?

If you check this line xhr.open(“PUT”, this.uploadPath, true); on line #3446 you can see that “this.uploadPath” is undefined

this is the direct link https://github.com/Backendless/JS-SDK/blob/master/libs/backendless.js#L3446

the “uploadPath” variable is assigned here:


I confirm you that the problem come from the variabile “this.uploadPath” that got undefined during the upload.

I tried to override manually: "https://api.backendless.com/v1/files/binary/folder/test.jpg?overwrite=true"; and It works.

Or better. It upload without any problem the file on backendless but I was’n able to remove this error:

backendless.js:3486 Uncaught Objectmessage: ""statusCode: 0__proto__: ObjectsendEncoded @ backendless.js:3486

Therefore I don’t know if the operation goes well or not.

I know, infact I put a console.log after that line and the variable is full assigned, but when called from the sendEncoded function it is undefined

I fixed in this way.

First I use a closure on line 3576 to maintain both event from onloadend and from the reader:

 reader.onloadend =  (function(f) {
            return function(e){

Then I adapted the sendEncoded method on line 3432 whit this code:

function sendEncoded(e1, e2) {
        var xhr         = new XMLHttpRequest(),
            boundary    = '-backendless-multipart-form-boundary-' + getNow(),
            badResponse = function(xhr) {
                var result = {};
                try {
                    result = JSON.parse(xhr.responseText);
                } catch (e) {
                    result.message = xhr.responseText;
                result.statusCode = xhr.status;
                return result;
        xhr.open("PUT", e2.uploadPath, true);
        xhr.setRequestHeader('Content-Type', 'text/plain');
        xhr.setRequestHeader('application-id', Backendless.applicationId);
        xhr.setRequestHeader("secret-key", Backendless.secretKey);
        xhr.setRequestHeader("application-type", "JS");

        if ((currentUser != null && currentUser["user-token"])) {
            xhr.setRequestHeader("user-token", currentUser["user-token"]);
        } else if (Backendless.LocalCache.exists("user-token")) {
            xhr.setRequestHeader("user-token", Backendless.LocalCache.get("user-token"));

        if (UIState !== null) {
            xhr.setRequestHeader("uiState", UIState);

        var asyncHandler = e2.asyncHandler;

        if (asyncHandler) {
            xhr.onreadystatechange = function() {
                if (xhr.readyState == 4) {
                    if (xhr.status >= 200 && xhr.status < 300) {
                    } else {


        if (asyncHandler) {
            return xhr;

        if (xhr.status >= 200 && xhr.status < 300) {
            return xhr.responseText ? JSON.parse(xhr.responseText) : true;
        } else {
            throw badResponse(xhr);

I think that there is the same problem on the send method, but I don’t need it so I didn’t changed it
Please check my changes and, if you agree, pull on github

Michele Riso

Our JS devs will review the code. Could you please submit a pull request for the changes?

Yes. I’ll do tomorrow.


Thanks! Were you running the code in a mobile browser or in a Ionic/Cordova app?

Both mobile browser and Cordova App with AngularJs.

Hi Michele,
I can’t reproduce your problem. I’ve used the version of JS-SDK from GitHub (because the fix of this problem is not released yet).
I put the console.log(this) in the 3447 line as you had advised. Then I run next code in the console of my browser (see attached screenshot).
As you can see everything works.
Please, provide us full example to reproduce this issue.

Regards, Ilya

I don’t know what to say… I tried another time with the version on github, but the same error…
the THIS object does not have the correct variables…

I don’t figure out why it does not work in my case… Maybe id because I use Cordova or maybe is because I’m using AngularJS?