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

Question

I Don\'t understand that... call its always undefined

Create the mock file:

var mockFile = { name: \"Filename\", size: 12345 };
         


        

Answer 1

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

Answer 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');
}

Answer 3

 var mockFile = { name: "banner2.jpg", size: 12345, uuid: "085b2b23-70e7-4175-8355-89937d8d46f2" };
 myDropzone.emit("addedfile", mockFile);
 myDropzone.options.thumbnail.call(myDropzone, mockFile, "https://your-thumbnail-image.jpg");

On Init-Function of the Dropzone-Object init: function() { call this:

  this.on("addedfile", function(file) {
                        //Access the preview element with file.previewElement and add event listeners, etc... to it.
                        var a = document.createElement('a');
                        a.setAttribute('href',"{{{protokoll}}}://{{{HTTP_HOST}}}/a-getfiledb.php?uuid="+file.uuid);
                        a.setAttribute('class',"btn btn-success");
                        a.setAttribute('style',"width:50%; margin-top:5px; border-left:1px solid black; cursor:pointer;");
                        a.innerHTML = "<i class='glyphicon glyphicon-download-alt'></i>";
                        file.previewTemplate.appendChild(a);
  });