How can I show you the files already stored on server using Dropzone.js

Solution 1:

Finally !!

$(function() {
    var mockFile = { name: "banner2.jpg", size: 12345 };
    var myDropzone = new Dropzone("#my-awesome-dropzone");
    myDropzone.options.addedfile.call(myDropzone, mockFile);
    myDropzone.options.thumbnail.call(myDropzone, mockFile, "http://localhost/test/drop/uploads/banner2.jpg");
})

Solution 2:

You can also do with the following code:

  <script>
        Dropzone.options.myAwesomeDropzone = false;
        Dropzone.autoDiscover = false;
        $("#image").dropzone({
            url: "http://someserver.com/upload.php",
            paramName: "image", // The name that will be used to transfer the file
            maxFilesize: 2, // MB
            maxFiles: 5,
            parallelUploads: 5,
            addRemoveLinks: true,
            dictMaxFilesExceeded: "You can only upload upto 5 images",
            dictRemoveFile: "Delete",
            dictCancelUploadConfirmation: "Are you sure to cancel upload?",
            accept: function (file, done) {
                console.log(file)
                if ((file.type).toLowerCase() != "image/jpg" &&
                        (file.type).toLowerCase() != "image/gif" &&
                        (file.type).toLowerCase() != "image/jpeg" &&
                        (file.type).toLowerCase() != "image/png"
                        ) {
                    done("Invalid file");
                }
                else {
                    done();
                }
            },
            init: function () {
                var mockFile = { name: "myimage.jpg", size: 12345, type: 'image/jpeg' };
                this.addFile.call(this, mockFile);
                this.options.thumbnail.call(this, mockFile, "http://someserver.com/myimage.jpg");
            }
        });
    </script>

EDIT

Since update of Dropzone 4.0 init function can be called as:

init: function () {
   var mockFile = { name: "myimage.jpg", size: 12345, type: 'image/jpeg' };       
   this.options.addedfile.call(this, mockFile);
   this.options.thumbnail.call(this, mockFile, "http://someserver.com/myimage.jpg");
   mockFile.previewElement.classList.add('dz-success');
   mockFile.previewElement.classList.add('dz-complete');
}

Solution 3:

my solution for >= 4.0, basing on "How to show files already stored on server": https://github.com/enyo/dropzone/wiki/FAQ

maxFiles: 1,

init: function () {
    this.on('maxfilesexceeded', function (file) {
        this.removeAllFiles();
        this.addFile(file);
    });

    var mocks = $dropzone.data('dropzone');
    for (var i = 0; i < mocks.length; i++) {
        var mock = mocks[i];
        mock.accepted = true;

        this.files.push(mock);
        this.emit('addedfile', mock);
        this.createThumbnailFromUrl(mock, mock.url);
        this.emit('complete', mock);
    }
}

Solution 4:

Based on punky's excellent answer above, you should not forget to add this._updateMaxFilesReachedClass(); at the end, like so:

init: function () {
    var mockFile = { name: <filename>, size: <filesize>, type: <filetype>, url: <file_url> };
    this.files.push(mockFile);
    this.emit('addedfile', mockFile);
    this.createThumbnailFromUrl(mockFile, mockFile.url);
    this.emit('complete', mockFile);
    this._updateMaxFilesReachedClass();
}

Solution 5:

In this answer https://stackoverflow.com/a/17763511, it's implemeneted with emmiting a thumbnail event.

Following is an example of doing it using createThumbnailFromUrl.

HTML element;

<form id="sample-img" action="/upload" class="dropzone">
    <div class="dz-default dz-message"></div>
</form>

JS code;

previewThumbailFromUrl({
    selector: 'sample-img',
    fileName: 'sampleImg',
    imageURL: '/images/sample.png'
});

function previewThumbailFromUrl(opts) {
    var imgDropzone = Dropzone.forElement("#" + opts.selector);
    var mockFile = {
        name: opts.fileName,
        size: 12345,
        accepted: true,
        kind: 'image'
    };
    imgDropzone.emit("addedfile", mockFile);
    imgDropzone.files.push(mockFile);
    imgDropzone.createThumbnailFromUrl(mockFile, opts.imageURL, function() {
        imgDropzone.emit("complete", mockFile);
    });
}

Working Samples on JSFiddle:

1. Load images on same domain
2. Load images with crossOrigin