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A JavaScript library providing multiple simultaneous, stable, fault-tolerant and resumable/restartable file uploads via the HTML5 File API.

Forked flow.js but refactor it.

The library is designed to introduce fault-tolerance into the upload of large files through HTTP. This is done by splitting each file into small chunks. Then, whenever the upload of a chunk fails, uploading is retried until the procedure completes. This allows uploads to automatically resume uploading after a network connection is lost either locally or to the server. Additionally, it allows for users to pause, resume and even recover uploads without losing state because only the currently uploading chunks will be aborted, not the entire upload.

Uploader (simple-uploader.js) does not have any external dependencies other than the HTML5 File API. This is relied on for the ability to chunk files into smaller pieces. Currently, this means that support is limited to Firefox 4+, Chrome 11+, Safari 6+ and Internet Explorer 10+.

Samples and examples are available in the samples/ folder. Please push your own as Markdown to help document the project.

• Treat Folder and File as Uploader.File

• Treat Uploader as a root Folder

• New fileList property which contains files and folders

Download a latest build from https://github.com/simple-uploader/Uploader/releases/ it contains development and minified production files in dist/ folder.

or use npm:

npm install simple-uploader.js

or use git clone

git clone https://github.com/simple-uploader/Uploader

A new Uploader object is created with information of what and where to post:

var uploader = new Uploader({
  target: '/api/photo/redeem-upload-token', 
  query: { upload_token: 'my_token' }
})
// Uploader isn't supported, fall back on a different method
if (!uploader.support) location.href = '/some-old-crappy-uploader'

To allow files to be either selected and drag-dropped, you'll assign drop target and a DOM item to be clicked for browsing:

uploader.assignBrowse(document.getElementById('browseButton'))
uploader.assignDrop(document.getElementById('dropTarget'))

After this, interaction with Uploader.js is done by listening to events:

uploader.on('fileAdded', function (file, event) {
  console.log(file, event)
})
uploader.on('fileSuccess', function (rootFile, file, message) {
  console.log(rootFile, file, message)
})
uploader.on('fileComplete', function (rootFile) {
  console.log(rootFile)
})
uploader.on('fileError', function (rootFile, file, message) {
  console.log(rootFile, file, message)
})

Most of the magic for Uploader.js happens in the user's browser, but files still need to be reassembled from chunks on the server side. This should be a fairly simple task and can be achieved in any web framework or language, which is able to receive file uploads.

To handle the state of upload chunks, a number of extra parameters are sent along with all requests:

• chunkNumber: The index of the chunk in the current upload. First chunk is 1 (no base-0 counting here).
• totalChunks: The total number of chunks.
• chunkSize: The general chunk size. Using this value and totalSize you can calculate the total number of chunks. Please note that the size of the data received in the HTTP might be greater than chunkSize of this for the last chunk for a file.
• totalSize: The total file size.
• identifier: A unique identifier for the file contained in the request.
• filename: The original file name (since a bug in Firefox results in the file name not being transmitted in chunk multipart posts).
• relativePath: The file's relative path when selecting a directory (defaults to file name in all browsers except Chrome).

You should allow for the same chunk to be uploaded more than once; this isn't standard behaviour, but on an unstable network environment it could happen, and this case is exactly what Uploader.js is designed for.

For every request, you can confirm reception in HTTP status codes (can be change through the permanentErrors option):

• 200, 201, 202: The chunk was accepted and correct. No need to re-upload.
• 404, 415. 500, 501: The file for which the chunk was uploaded is not supported, cancel the entire upload.
• Anything else: Something went wrong, but try reuploading the file.

Enabling the testChunks option will allow uploads to be resumed after browser restarts and even across browsers (in theory you could even run the same file upload across multiple tabs or different browsers). The POST data requests listed are required to use Uploader.js to receive data, but you can extend support by implementing a corresponding GET request with the same parameters:

• If this request returns a 200, 201 or 202 HTTP code, the chunks is assumed to have been completed.
• If request returns a permanent error status, upload is stopped.
• If request returns anything else, the chunk will be uploaded in the standard fashion.

After this is done and testChunks enabled, an upload can quickly catch up even after a browser restart by simply verifying already uploaded chunks that do not need to be uploaded again.

The object is loaded with a configuration options:

var r = new Uploader({ opt1: 'val', ...})

Available configuration options are:

• target The target URL for the multipart POST request. This can be a string or a function. If a function, it will be passed a Uploader.File, a Uploader.Chunk and isTest boolean (Default: /)
• singleFile Enable single file upload. Once one file is uploaded, second file will overtake existing one, first one will be canceled. (Default: false)
• chunkSize The size in bytes of each uploaded chunk of data. The last uploaded chunk will be at least this size and up to two the size, see Issue #51 for details and reasons. (Default: 1*1024*1024)
• forceChunkSize Force all chunks to be less or equal than chunkSize. Otherwise, the last chunk will be greater than or equal to chunkSize. (Default: false)
• simultaneousUploads Number of simultaneous uploads (Default: 3)
• fileParameterName The name of the multipart POST parameter to use for the file chunk (Default: file)
• query Extra parameters to include in the multipart POST with data. This can be an object or a function. If a function, it will be passed a Uploader.File, a Uploader.Chunk object and a isTest boolean (Default: {})
• headers Extra headers to include in the multipart POST with data. If a function, it will be passed a Uploader.File, a Uploader.Chunk object and a isTest boolean (Default: {})
• withCredentials Standard CORS requests do not send or set any cookies by default. In order to include cookies as part of the request, you need to set the withCredentials property to true. (Default: false)
• method Method to use when POSTing chunks to the server (multipart or octet) (Default: multipart)
• testMethod HTTP method to use when chunks are being tested. If set to a function, it will be passed a Uploader.File and a Uploader.Chunk arguments. (Default: GET)
• uploadMethod HTTP method to use when chunks are being uploaded. If set to a function, it will be passed a Uploader.File arguments. (Default: POST)
• allowDuplicateUploads Once a file is uploaded, allow reupload of the same file. By default, if a file is already uploaded, it will be skipped unless the file is removed from the existing Uploader object. (Default: false)
• prioritizeFirstAndLastChunk Prioritize first and last chunks of all files. This can be handy if you can determine if a file is valid for your service from only the first or last chunk. For example, photo or video meta data is usually located in the first part of a file, making it easy to test support from only the first chunk. (Default: false)
• testChunks Make a GET request to the server for each chunks to see if it already exists. If implemented on the server-side, this will allow for upload resumes even after a browser crash or even a computer restart. (Default: true)
• preprocess Optional function to process each chunk before testing & sending. To the function it will be passed the chunk as parameter, and should call the preprocessFinished method on the chunk when finished. (Default: null)
• initFileFn Optional function to initialize the fileObject. To the function it will be passed a Uploader.File arguments.
• readFileFn Optional function wrapping reading operation from the original file. To the function it will be passed the Uploader.File, the startByte and endByte, the fileType and the Uploader.Chunk. And should call the readFinished method with bytes arguments on the chunk when finished.
• checkChunkUploadedByResponse Optional function to check chunk was uploaded by XHR response. To the function it will be passed the Uploader.Chunk and the response message. You do not need to upload(test) all chunks now, see Issue #1 for details and reasons, sample.
• generateUniqueIdentifier Override the function that generates unique identifiers for each file. (Default: null)
• maxChunkRetries The maximum number of retries for a chunk before the upload is failed. Valid values are any positive integer and undefined for no limit. (Default: 0)
• chunkRetryInterval The number of milliseconds to wait before retrying a chunk on a non-permanent error. Valid values are any positive integer and undefined for immediate retry. (Default: undefined)
• progressCallbacksInterval The time interval in milliseconds between progress reports. Set it to 0 to handle each progress callback. (Default: 500)
• speedSmoothingFactor Used for calculating average upload speed. Number from 1 to 0. Set to 1 and average upload speed wil be equal to current upload speed. For longer file uploads it is better set this number to 0.02, because time remaining estimation will be more accurate. This parameter must be adjusted together with progressCallbacksInterval parameter. (Default 0.1)
• successStatuses Response is success if response status is in this list (Default: [200,201, 202])
• permanentErrors Response fails if response status is in this list (Default: [404, 415, 500, 501])
• initialPaused Initial paused state, default false.
• processResponse Process xhr response, default function (response, cb) { cb(null, response) }. After 0.5.2, processResponse will be called with arguments: (response, cb, Uploader.File, Uploader.Chunk).
• processParams Process xhr params, default function (params) {return params}. After 0.5.2, processParams will be called with arguments: (params, Uploader.File, Uploader.Chunk, isTest).

• .support A boolean value indicator whether or not Uploader.js is supported by the current browser.
• .supportDirectory A boolean value, which indicates if browser supports directory uploads.
• .opts A hash object of the configuration of the Uploader.js instance.
• .files An array of Uploader.File file objects added by the user (see full docs for this object type below).
• .fileList An array of Uploader.File file(folder) objects added by the user (see full docs for this object type below), but it treated Folder as a Uploader.File Object.

• .assignBrowse(domNodes, isDirectory, singleFile, attributes) Assign a browse action to one or more DOM nodes.

  • domNodes array of dom nodes or a single node.
  • isDirectory Pass in true to allow directories to be selected (Chrome only, support can be checked with supportDirectory property).
  • singleFile To prevent multiple file uploads set this to true. Also look at config parameter singleFile.
  • attributes Pass object of keys and values to set custom attributes on input fields. For example, you can set accept attribute to image/*. This means that user will be able to select only images. Full list of attributes: https://www.w3.org/wiki/HTML/Elements/input/file

  Note: avoid using a and button tags as file upload buttons, use span instead.

• .assignDrop(domNodes) Assign one or more DOM nodes as a drop target.

• .unAssignDrop(domNodes) Unassign one or more DOM nodes as a drop target.

• .on(event, callback) Listen for event from Uploader.js (see below)

• .off([event, [callback]]):

  • .off(event) Remove all callbacks of specific event.
  • .off(event, callback) Remove specific callback of event. callback should be a Function.

• .upload() Start or resume uploading.

• .pause() Pause uploading.

• .resume() Resume uploading.

• .cancel() Cancel upload of all Uploader.File objects and remove them from the list.

• .progress() Returns a float between 0 and 1 indicating the current upload progress of all files.

• .isUploading() Returns a boolean indicating whether or not the instance is currently uploading anything.

• .addFile(file) Add a HTML5 File object to the list of files.

• .removeFile(file) Cancel upload of a specific Uploader.File object on the list from the list.

• .getFromUniqueIdentifier(uniqueIdentifier) Look up a Uploader.File object by its unique identifier.

• .getSize() Returns the total size of the upload in bytes.

• .sizeUploaded() Returns the total size uploaded of all files in bytes.

• .timeRemaining() Returns remaining time to upload all files in seconds. Accuracy is based on average speed. If speed is zero, time remaining will be equal to positive infinity Number.POSITIVE_INFINITY

• .change(event) File input change event.
• .dragover(event) Drop area dragover event.
• .dragenter(event) Drop area dragenter event.
• .dragleave(event) Drop area dragleave event.
• .fileSuccess(rootFile, file, message, chunk) A specific file was completed. First argument rootFile is the root Uploader.File instance which contains or equal the completed file, second argument file argument is instance of Uploader.File too, it's the current completed file object, third argument message contains server response. Response is always a string. Fourth argument chunk is instance of Uploader.Chunk. You can get response status by accessing xhr object chunk.xhr.status.
• .fileComplete(rootFile) A root file(Folder) was completed.
• .fileProgress(rootFile, file, chunk) Uploading progressed for a specific file.
• .fileAdded(file, event) This event is used for file validation. To reject this file return false. This event is also called before file is added to upload queue, this means that calling uploader.upload() function will not start current file upload. Optionally, you can use the browser event object from when the file was added.
• .filesAdded(files, fileList, event) Same as fileAdded, but used for multiple file validation.
• .filesSubmitted(files, fileList, event) Same as filesAdded, but happens after the file is added to upload queue. Can be used to start upload of currently added files.
• .fileRemoved(file) The specific file was removed from the upload queue. Combined with filesSubmitted, can be used to notify UI to update its state to match the upload queue.
• .fileRetry(rootFile, file, chunk) Something went wrong during upload of a specific file, uploading is being retried.
• .fileError(rootFile, file, message, chunk) An error occurred during upload of a specific file.
• .uploadStart() Upload has been started.
• .complete() Uploading completed.
• .catchAll(event, ...) Listen to all the events listed above with the same callback function.

• .uploader A back-reference to the parent Uploader object.
• .name The name of the file(folder).
• .averageSpeed Average upload speed, bytes per second.
• .currentSpeed Current upload speed, bytes per second.
• .paused Indicated if file(folder) is paused.
• .error Indicated if file(folder) has encountered an error.
• .isFolder Indicated if file(folder) is an Directory.

If .isFolder is false then these properties will be added:

• .file The correlating HTML5 File object.
• .relativePath The relative path to the file (defaults to file name if relative path doesn't exist).
• .size Size in bytes of the file.
• .uniqueIdentifier A unique identifier assigned to this file object. This value is included in uploads to the server for reference, but can also be used in CSS classes etc when building your upload UI.
• .chunks An array of Uploader.Chunk items. You shouldn't need to dig into these.

• .getRoot() Returns the file's root Uploader.File instance in uploader.fileList.
• .progress() Returns a float between 0 and 1 indicating the current upload progress of the file.
• .pause() Pause uploading the file.
• .resume() Resume uploading the file.
• .cancel() Abort uploading the file and delete it from the list of files to upload.
• .retry() Retry uploading the file.
• .bootstrap() Rebuild the state of a Uploader.File object, including reassigning chunks and XMLHttpRequest instances.
• .isUploading() Returns a boolean indicating whether file chunks is uploading.
• .isComplete() Returns a boolean indicating whether the file has completed uploading and received a server response.
• .sizeUploaded() Returns size uploaded in bytes.
• .timeRemaining() Returns remaining time to finish upload file in seconds. Accuracy is based on average speed. If speed is zero, time remaining will be equal to positive infinity Number.POSITIVE_INFINITY
• .getExtension() Returns file extension in lowercase.
• .getType() Returns file type.

Uploader.js was inspired by and evolved from https://github.com/flowjs/flow.js and https://github.com/23/resumable.js.