How to limit the number of dropzone.js files uploaded?

Question

Depending on the use case, how do I constrain the number of files that dropzone.js will allow?

For example, I might need to only allow 1, 2, or 4 files uploaded.

It's not uploadMultiple. Unfortunately, uploadMultiple only applies to the number of files handled per request.

Parian

Use maxFiles. That will help – Singlecross

Actually maxFiles is the answer for this question, there is no need to write more code. thanks. – Mammalogy

Answer 1

Nowell pointed it out that this has been addressed as of August 6th, 2013. A working example using this form might be:

<form class="dropzone" id="my-awesome-dropzone"></form>

You could use this JavaScript:

Dropzone.options.myAwesomeDropzone = {
  maxFiles: 1,
  accept: function(file, done) {
    console.log("uploaded");
    done();
  },
  init: function() {
    this.on("maxfilesexceeded", function(file){
        alert("No more files please!");
    });
  }
};

The dropzone element even gets a special style, so you can do things like:

<style>
  .dz-max-files-reached {background-color: red};
</style>

Parian

shouldn't it be <form class="dropzone" id="myAwesomeDropzone"></form> ? – Eyre

@MKYung I know this is almost a year after the fact, but the id is pulled by Dropzone and enyo makes the camel case for you. So calling it is much easier. (Can be kinda confusing at first obviously... but it works so I don't complain.) – Bugbane

That works fine when adding 1 file, then the next. Although, if you select multiple files on your machine and drag them all to the dropzone form, all of them get added. How to prevent that? – Indemnification

It only worked for me if and only if i put <script>Dropzone...</script> above <form> – Cleavland

Answer 2

I achieved this a slightly different way. I just remove the old dropped file any time a new file is added. It acts as overwriting the file which was the user experience I was going for here.

Dropzone.options.myAwesomeDropzone = {
  accept: function(file, done) {
    console.log("uploaded");
    done();
  },
  init: function() {
    this.on("addedfile", function() {
      if (this.files[1]!=null){
        this.removeFile(this.files[0]);
      }
    });
  }
};

Koblas

This works really well. The other answers don't. You can also do the same work right within the accept function. this.files exists there as well. This would shorten the code a bit. – Alfy

where to put this code inside dropzone.js or html codes where form placed – Vivyan

This is a great answer to a different question (How to overwrite a previously uploaded file). – Mucous

After trying the other answers, the is the only one that worked exactly how I wanted. Should be accepted answer, imho. – Frigidarium

PERFECT!! Works exactly like the way I want – Kristikristian

For me on current Chrome, files[1] is undefined when there is only one file, so the if condition always returns true. Perhaps just change to if (this.files[1])? – Jujube

Thank you Sir! I have been searching long for this. :) – Hirsch

Answer 3

I thought that the most intuitive single file upload process was to replace the previous file upon a new entry.

  $(".drop-image").dropzone({
    url: '/cart?upload-engraving=true',
    maxFiles: 1,
    maxfilesexceeded: function(file) {
        this.removeAllFiles();
        this.addFile(file);
    }
})

Headroom

This didn't work for me -- but the other answer by @Koblas does. – Riffe

Thank you for this hint, that's what I was searching for. Also don't forget to maintain the file server side if applicable (ie: previous file getting deleted). – Counterwork

This does not work when autoProcessQueue is false. However, it triggers when maxFiles is 0 and autoProcessQueue is false. This must be a bug. – Zenger

Worked perfectly fine for me, and agree with this is being most intuitive single file upload process :) – Publicist

+1 This answer is a much better solution for the end-user. Works well on my project using the init: function(){ this.on('maxfilesexceeded', function(file){ this.removeAllFiles(); this.addFile(file); }); } option, even with the added option autoProcessQueue: false. – Bronwen

@Bronwen good to hear this still is useful so many years later! – Democrat

For me it worked when I added true to removeAllFiles like this: this.removeAllFiles(true); – Driggers

Answer 4

maxFiles: 1 does the job but if you also want to remove the additional files you can use this sample code taken from the Wiki page:

How can I limit the number of files?

You're in luck! Starting with 3.7.0 Dropzone supports the maxFiles option. Simply set it to the desired quantity and you're good to go. If you don't want the rejected files to be viewed, simply register for the maxfilesexceeded event, and remove the file immediately:

myDropzone.on("maxfilesexceeded", function(file)
{
    this.removeFile(file);
});

Await

So much underrated answer. – Normalcy

Answer 5

Alternative solution that worked really well for me:

init: function() {
    this.on("addedfile", function(event) {
        while (this.files.length > this.options.maxFiles) {
            this.removeFile(this.files[0]);
        }
    });
}

Specialize

Answer 6

You can limit the number of files uploaded by changing in dropezone.js

Dropzone.prototype.defaultOptions = { maxFiles: 10, }

Waine

More of these options can be viewed here: dropzonejs.com/#configuration-options – Midvictorian

Answer 7

1. Set maxFiles Count: maxFiles: 1
2. In maxfilesexceeded event, clear all files and add a new file:

event: Called for each file that has been rejected because the number of files exceeds the maxFiles limit.

var myDropzone = new Dropzone("div#yourDropzoneID", { url: "/file/post", 
uploadMultiple: false, maxFiles: 1 });

myDropzone.on("maxfilesexceeded", function (file) {
    myDropzone.removeAllFiles();
    myDropzone.addFile(file);
});

Threecornered

Answer 8

it looks like maxFiles is the parameter you are looking for.

https://github.com/enyo/dropzone/blob/master/src/dropzone.coffee#L667

Eads

This got added two days after I opened this question. ;-) – Parian

Answer 9

Why do not you just use CSS to disable the click event. When max files is reached, Dropzone will automatically add a class of dz-max-files-reached.

Use css to disable click on dropzone:

.dz-max-files-reached {
          pointer-events: none;
          cursor: default;
}

Credit: this answer

Permanent

you won't be able also to remove uploaded by mistake files. – Beebeebe

Answer 10

The problem with the solutions provided is that you can only upload 1 file ever. In my case I needed to upload only 1 file at a time (on click or on drop).

This was my solution..

    Dropzone.options.myDropzone = {
        maxFiles: 2,
        init: function() {
            this.handleFiles = function(files) {
                var file, _i, _len, _results;
                _results = [];
                for (_i = 0, _len = files.length; _i < _len; _i++) {
                    file = files[_i];
                    _results.push(this.addFile(file));
                    // Make sure we don't handle more files than requested
                    if (this.options.maxFiles != null && this.options.maxFiles > 0 && _i >= (this.options.maxFiles - 1)) {
                        break;
                    }
                }
                return _results;
            };
            this._addFilesFromItems = function(items) {
                var entry, item, _i, _len, _results;
                _results = [];
                for (_i = 0, _len = items.length; _i < _len; _i++) {
                    item = items[_i];
                    if ((item.webkitGetAsEntry != null) && (entry = item.webkitGetAsEntry())) {
                        if (entry.isFile) {
                            _results.push(this.addFile(item.getAsFile()));
                        } else if (entry.isDirectory) {
                            _results.push(this._addFilesFromDirectory(entry, entry.name));
                        } else {
                            _results.push(void 0);
                        }
                    } else if (item.getAsFile != null) {
                        if ((item.kind == null) || item.kind === "file") {
                            _results.push(this.addFile(item.getAsFile()));
                        } else {
                            _results.push(void 0);
                        }
                    } else {
                        _results.push(void 0);
                    }
                    // Make sure we don't handle more files than requested
                    if (this.options.maxFiles != null && this.options.maxFiles > 0 && _i >= (this.options.maxFiles - 1)) {
                        break;
                    }
                }
                return _results;
            };
        }
    };

Hope this helps ;)

Abrasion

Answer 11

I'd like to point out. maybe this just happens to me, HOWEVER, when I use this.removeAllFiles() in dropzone, it fires the event COMPLETE and this blows, what I did was check if the fileData was empty or not so I could actually submit the form.

Pliable

Answer 12

You can also add in callbacks - here I'm using Dropzone for Angular

dzCallbacks = {
    'addedfile' : function(file){
        $scope.btSend = false;
        $scope.form.logoFile = file;
    },
    'success' : function(file, xhr){
        $scope.btSend = true;
        console.log(file, xhr);
    },
    'maxfilesexceeded': function(file) {
         $timeout(function() { 
            file._removeLink.click();
        }, 2000);
    }
}

Bobbinet

Answer 13

Dropzone.options.dpzSingleFile = {
    paramName: "file", // The name that will be used to transfer the file
    maxFiles: 1,
    init: function() {
        this.on("maxfilesexceeded", function(file) {
            this.removeAllFiles();
            this.addFile(file);
        });
    }
};

Bohemian