DropZonejs: Submit form without files - dropzone.js

Question

I've successfully integrated dropzone.js inside an existing form. This form posts the attachments and other inputs like checkboxes, etc.
When I submit the form with attachments, all the inputs post properly. However, I want to make it possible for the user to submit the form without any attachments. Dropzone doesn't allow the form submission unless there is an attachment.
Does anybody know how I can override this default behavior and submit the dropzone.js form without any attachments? Thank you!
$( document ).ready(function () {
Dropzone.options.fileUpload = { // The camelized version of the ID of the form element
// The configuration we've talked about above
autoProcessQueue: false,
uploadMultiple: true,
parallelUploads: 50,
maxFiles: 50,
addRemoveLinks: true,
clickable: "#clickable",
previewsContainer: ".dropzone-previews",
acceptedFiles: "image/*,application/pdf, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.openxmlformats-officedocument.spreadsheetml.template, application/vnd.openxmlformats-officedocument.presentationml.template, application/vnd.openxmlformats-officedocument.presentationml.slideshow, application/vnd.openxmlformats-officedocument.presentationml.presentation, application/vnd.openxmlformats-officedocument.presentationml.slide, application/vnd.openxmlformats-officedocument.wordprocessingml.document, application/vnd.openxmlformats-officedocument.wordprocessingml.template, application/vnd.ms-excel.addin.macroEnabled.12, application/vnd.ms-excel.sheet.binary.macroEnabled.12,text/rtf,text/plain,audio/*,video/*,.csv,.doc,.xls,.ppt,application/vnd.ms-powerpoint,.pptx",
// The setting up of the dropzone
init: function() {
var myDropzone = this;
// First change the button to actually tell Dropzone to process the queue.
this.element.querySelector("button[type=submit]").addEventListener("click", function(e) {
// Make sure that the form isn't actually being sent.
e.preventDefault();
e.stopPropagation();
myDropzone.processQueue();
});
// Listen to the sendingmultiple event. In this case, it's the sendingmultiple event instead
// of the sending event because uploadMultiple is set to true.
this.on("sendingmultiple", function() {
// Gets triggered when the form is actually being sent.
// Hide the success button or the complete form.
});
this.on("successmultiple", function(files, response) {
window.location.replace(response.redirect);
exit();
});
this.on("errormultiple", function(files, response) {
$("#notifications").before('<div class="alert alert-error" id="alert-error"><button type="button" class="close" data-dismiss="alert">×</button><i class="icon-exclamation-sign"></i> There is a problem with the files being uploaded. Please check the form below.</div>');
exit();
});
}
}
});

Answer 1

Use the following:
$('input[type="submit"]').on("click", function (e) {
e.preventDefault();
e.stopPropagation();
var form = $(this).closest('#dropzone-form');
if (form.valid() == true) {
if (myDropzone.getQueuedFiles().length > 0) {
myDropzone.processQueue();
} else {
myDropzone.uploadFiles([]); //send empty
}
}
});
Reference: https://github.com/enyo/dropzone/issues/418

Answer 2

You should check if there are files in the queue. If the queue is empty call directly dropzone.uploadFile(). This method requires you to pass in a file. As stated on [caniuse][1], the File constructor isn't supported on IE/Edge, so just use Blob API, as File API is based on that.
The formData.append() method used in dropzone.uploadFile() requires you to pass an object which implements the Blob interface. That's the reason why you cannot pass in a normal object.
dropzone version 5.2.0 requires the upload.chunked option
if (this.dropzone.getQueuedFiles().length === 0) {
var blob = new Blob();
blob.upload = { 'chunked': this.dropzone.defaultOptions.chunking };
this.dropzone.uploadFile(blob);
} else {
this.dropzone.processQueue();
}

Answer 3

Depending on your situation you could simply submit the form:
if (myDropzone.getQueuedFiles().length > 0) {
myDropzone.processQueue();
} else {
$("#my_form").submit();
}

Answer 4

The first approach is kind of too expensive for me, I would not like to dive into the source code and modify it,
If you happen to be like me , use this.
function submitMyFormWithData(url)
{
formData = new FormData();
//formData.append('nameOfInputField', $('input[name="nameOfInputField"]').val() );
$.ajax({
url: url,
data: formData,
processData: false,
contentType: false,
type: 'POST',
success: function(data){
alert(data);
}
});
}
And in your dropzone script
$("#submit").on("click", function(e) {
// Make sure that the form isn't actually being sent.
e.preventDefault();
e.stopPropagation();
if (myDropzone.getQueuedFiles().length > 0)
{
myDropzone.processQueue();
} else {
submitMyFormWithData(ajaxURL);
}
});

Answer 5

I tried Matija Grcic's answer and I got the following error:
Uncaught TypeError: Cannot read property 'name' of undefined
And I didn't want to modify the dropzone source code, so I did the following:
if (myDropzone.getQueuedFiles().length > 0) {
myDropzone.processQueue();
} else {
myDropzone.uploadFiles([{name:'nofiles'}]); //send empty
}
Note: I'm passing an object inside the array to the uploadFiles function.
Then I check server-side, if name != 'nofiles' do upload stuff.

Answer 6

Pretty simple, you stop the propagation ONLY if you have files to be submitted via Dropzone:
// First change the button to actually tell Dropzone to process the queue.
this.element.querySelector("button[type=submit]").addEventListener("click", function(e) {
// Stop the propagation ONLY if you have files to be submitted via Dropzone
if (myDropzone.getQueuedFiles().length > 0) {
e.preventDefault();
e.stopPropagation();
myDropzone.processQueue();
}
});

Answer 7

I have successfully used :
submitButton.addEventListener("click", function () {
if(wrapperThis.files.length){
error = `Please select a file`;
} else {
wrapperThis.processQueue();
}
});

Answer 8

My answer is based on the fact that the other answers don't allow for an Ajax based solution where an actual HTML form isn't actually being used. Additionally you may want the full form contents submitted when sending the Files for upload as well.
As you'll see, my form occurs in a modal outside of any form tag. On completion, the modal is triggered to close.
(FYI getForm returns the form as an object and not directly related to the answer. Also assumes use of jQuery)
init: function() {
var dzClosure = this;
// When saving what are we doing?
$('.saveBtn').off('click').on('click',function(e){
e.preventDefault();
e.stopPropagation();
if (dzClosure.getQueuedFiles().length > 0) {
dzClosure.processQueue();
dzClosure.on('queuecomplete',function(){
$('.modal:visible').modal('hide');
})
} else {
var params = getForm();
$.post(dzClosure.options.url,params,function(){
$('.modal:visible').modal('hide');
})
}
});
dzClosure.on('sending', function (data, xhr, formData) {
var extra = getForm();
for (key in extra){
formData.append(key,extra[key]);
}
});