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Document TOP » API Reference » Core Cordova Plugins » File Transfer Plugin

File Transfer Plugin

Tested Version: 1.6.3

Note

This document is based on the original Cordova docs available at Cordova Docs.

This plugin allows you to upload and download files.

This plugin defines global FileTransfer, FileUploadOptions constructors. Although in the global scope, they are not available until after the deviceready event.

document.addEventListener("deviceready", onDeviceReady, false);
function onDeviceReady() {
    console.log(FileTransfer);
}

Plugin ID

cordova-plugin-file-transfer

Adding the Plugin in Monaca

In order to use this plugin, please enable both File Transfer and File plugins in Monaca Cloud IDE because File Transfer plugin is depending on File plugin.

Supported Platforms

  • Android
  • iOS
  • Windows

API Reference

FileTransfer

The FileTransfer object provides a way to upload files using an HTTP multi-part POST or PUT request, and to download files.

Properties

  • onprogress: Called with a ProgressEvent whenever a new chunk of data is transferred. (Function)

Methods

  • upload: Sends a file to a server.
  • download: Downloads a file from server.
  • abort: Aborts an in-progress transfer.

upload

Parameters:

  • fileURL: Filesystem URL representing the file on the device or a data URI. For backwards compatibility, this can also be the full path of the file on the device. (See Backwards Compatibility Notes below)
  • server: URL of the server to receive the file, as encoded by encodeURI().
  • successCallback: A callback that is passed a FileUploadResult object. (Function)
  • errorCallback: A callback that executes if an error occurs retrieving the FileUploadResult. Invoked with a FileTransferError object. (Function)
  • options: Optional parameters (Object). Valid keys:
  • fileKey: The name of the form element. Defaults to file. (DOMString)
  • fileName: The file name to use when saving the file on the server. Defaults to image.jpg. (DOMString)
  • httpMethod: The HTTP method to use - either PUT or POST. Defaults to POST. (DOMString)
  • mimeType: The mime type of the data to upload. Defaults to image/jpeg. (DOMString)
  • params: A set of optional key/value pairs to pass in the HTTP request. (Object, key/value - DOMString)
  • chunkedMode: Whether to upload the data in chunked streaming mode. Defaults to true. (Boolean)
  • headers: A map of header name/header values. Use an array to specify more than one value. On iOS, FireOS, and Android, if a header named Content-Type is present, multipart form data will NOT be used. (Object)
  • trustAllHosts: Optional parameter, defaults to false. If set to true, it accepts all security certificates. This is useful since Android rejects self-signed security certificates. Not recommended for production use. Supported on Android and iOS. (boolean)
Example
// !! Assumes variable fileURL contains a valid URL to a text file on the device,
//    for example, cdvfile://localhost/persistent/path/to/file.txt

var win = function (r) {
    console.log("Code = " + r.responseCode);
    console.log("Response = " + r.response);
    console.log("Sent = " + r.bytesSent);
}

var fail = function (error) {
    alert("An error has occurred: Code = " + error.code);
    console.log("upload error source " + error.source);
    console.log("upload error target " + error.target);
}

var options = new FileUploadOptions();
options.fileKey = "file";
options.fileName = fileURL.substr(fileURL.lastIndexOf('/') + 1);
options.mimeType = "text/plain";

var params = {};
params.value1 = "test";
params.value2 = "param";

options.params = params;

var ft = new FileTransfer();
ft.upload(fileURL, encodeURI("http://some.server.com/upload.php"), win, fail, options);
Example with Upload Headers and Progress Events (Android and iOS only)
function win(r) {
    console.log("Code = " + r.responseCode);
    console.log("Response = " + r.response);
    console.log("Sent = " + r.bytesSent);
}

function fail(error) {
    alert("An error has occurred: Code = " + error.code);
    console.log("upload error source " + error.source);
    console.log("upload error target " + error.target);
}

var uri = encodeURI("http://some.server.com/upload.php");

var options = new FileUploadOptions();
options.fileKey="file";
options.fileName=fileURL.substr(fileURL.lastIndexOf('/')+1);
options.mimeType="text/plain";

var headers={'headerParam':'headerValue'};

options.headers = headers;

var ft = new FileTransfer();
ft.onprogress = function(progressEvent) {
    if (progressEvent.lengthComputable) {
        loadingStatus.setPercentage(progressEvent.loaded / progressEvent.total);
    } else {
        loadingStatus.increment();
    }
};
ft.upload(fileURL, uri, win, fail, options);

download

Parameters:

  • source: URL of the server to download the file, as encoded by encodeURI().
  • target: Filesystem url representing the file on the device. For backwards compatibility, this can also be the full path of the file on the device. (See Backwards Compatibility Notes below)
  • successCallback: A callback that is passed a FileEntry object. (Function)
  • errorCallback: A callback that executes if an error occurs when retrieving the FileEntry. Invoked with a FileTransferError object. (Function)
  • trustAllHosts: Optional parameter, defaults to false. If set to true, it accepts all security certificates. This is useful because Android rejects self-signed security certificates. Not recommended for production use. Supported on Android and iOS. (boolean)
  • options: Optional parameters, currently only supports headers (such as Authorization (Basic Authentication), etc).
Example
// !! Assumes variable fileURL contains a valid URL to a path on the device,
//    for example, cdvfile://localhost/persistent/path/to/downloads/

var fileTransfer = new FileTransfer();
var uri = encodeURI("http://some.server.com/download.php");

fileTransfer.download(
    uri,
    fileURL,
    function(entry) {
        console.log("download complete: " + entry.toURL());
    },
    function(error) {
        console.log("download error source " + error.source);
        console.log("download error target " + error.target);
        console.log("download error code" + error.code);
    },
    false,
    {
        headers: {
            "Authorization": "Basic dGVzdHVzZXJuYW1lOnRlc3RwYXNzd29yZA=="
        }
    }
);

abort

Aborts an in-progress transfer. The onerror callback is passed a FileTransferError object which has an error code of FileTransferError.ABORT_ERR.

Example
// !! Assumes variable fileURL contains a valid URL to a text file on the device,
//    for example, cdvfile://localhost/persistent/path/to/file.txt

var win = function(r) {
    console.log("Should not be called.");
}

var fail = function(error) {
    // error.code == FileTransferError.ABORT_ERR
    alert("An error has occurred: Code = " + error.code);
    console.log("upload error source " + error.source);
    console.log("upload error target " + error.target);
}

var options = new FileUploadOptions();
options.fileKey="file";
options.fileName="myphoto.jpg";
options.mimeType="image/jpeg";

var ft = new FileTransfer();
ft.upload(fileURL, encodeURI("http://some.server.com/upload.php"), win, fail, options);
ft.abort();

FileUploadResult

A FileUploadResult object is passed to the success callback of the FileTransfer object’s upload() method.

Properties

  • bytesSent: The number of bytes sent to the server as part of the upload. (long)
  • responseCode: The HTTP response code returned by the server. (long)
  • response: The HTTP response returned by the server. (DOMString)
  • headers: The HTTP response headers by the server. (Object)
  • Currently supported on iOS only.

iOS Quirks

  • Does not support responseCode or bytesSent.
  • Does not support uploads of an empty file with chunkedMode=true and multipartMode=false.

Windows Quirks

  • An option parameter with empty/null value is excluded in the upload operation due to the Windows API design.
  • chunkedMode is not supported and all uploads are set to non-chunked mode.

FileTransferError

A FileTransferError object is passed to an error callback when an error occurs.

Properties

  • code: One of the predefined error codes listed below. (Number)
  • source: URL to the source. (String)
  • target: URL to the target. (String)
  • http_status: HTTP status code. This attribute is only available when a response code is received from the HTTP connection. (Number)
  • body Response body. This attribute is only available when a response is received from the HTTP connection. (String)
  • exception: Either e.getMessage or e.toString (String)

Constants

  • 1 = FileTransferError.FILE_NOT_FOUND_ERR
  • 2 = FileTransferError.INVALID_URL_ERR
  • 3 = FileTransferError.CONNECTION_ERR
  • 4 = FileTransferError.ABORT_ERR
  • 5 = FileTransferError.NOT_MODIFIED_ERR

Windows Quirks

  • The plugin implementation is based on BackgroundDownloader/BackgroundUploader, which entails the latency issues on Windows devices (creation/starting of an operation can take up to a few seconds). You can use XHR or HttpClient as a quicker alternative for small downloads.

Backwards Compatibility Notes

Previous versions of this plugin would only accept device-absolute-file-paths as the source for uploads, or as the target for downloads. These paths would typically be of the form:

/var/mobile/Applications/<application UUID>/Documents/path/to/file  (iOS)
/storage/emulated/0/path/to/file                                    (Android)

For backwards compatibility, these paths are still accepted, and if your application has recorded paths like these in persistent storage, then they can continue to be used.

These paths were previously exposed in the fullPath property of FileEntry and DirectoryEntry objects returned by the File plugin. New versions of the File plugin however, no longer expose these paths to JavaScript.

If you are upgrading to a new (1.0.0 or newer) version of File, and you have previously been using entry.fullPath as arguments to download() or upload(), then you will need to change your code to use filesystem URLs instead.

FileEntry.toURL() and DirectoryEntry.toURL() return a filesystem URL of the form:

cdvfile://localhost/persistent/path/to/file

which can be used in place of the absolute file path in both download() and upload() methods.

Sample: Download and Upload Files

Use the File-Transfer plugin to upload and download files. In these examples, we demonstrate several tasks like:

Download a Binary File to the application cache

Use the File plugin with the File-Transfer plugin to provide a target for the files that you download (the target must be a FileEntry object). Before you download the file, create a DirectoryEntry object by using resolveLocalFileSystemURL and calling fs.root in the success callback. Use the getFile method of DirectoryEntry to create the target file.

window.requestFileSystem(window.TEMPORARY, 5 * 1024 * 1024, function (fs) {

    console.log('file system open: ' + fs.name);

    // Make sure you add the domain name to the Content-Security-Policy <meta> element.
    var url = 'http://cordova.apache.org/static/img/cordova_bot.png';
    // Parameters passed to getFile create a new file or return the file if it already exists.
    fs.root.getFile('downloaded-image.png', { create: true, exclusive: false }, function (fileEntry) {
        download(fileEntry, url, true);

    }, onErrorCreateFile);

}, onErrorLoadFs);

Note

For persistent storage, pass LocalFileSystem.PERSISTENT to requestFileSystem.

When you have the FileEntry object, download the file using the download method of the FileTransfer object. The 3rd argument to the download function of FileTransfer is the success callback, which you can use to call the app’s readBinaryFile function. In this code example, the entry variable is a new FileEntry object that receives the result of the download operation.

function download(fileEntry, uri, readBinaryData) {

    var fileTransfer = new FileTransfer();
    var fileURL = fileEntry.toURL();

    fileTransfer.download(
        uri,
        fileURL,
        function (entry) {
            console.log("Successful download...");
            console.log("download complete: " + entry.toURL());
            if (readBinaryData) {
              // Read the file...
              readBinaryFile(entry);
            }
            else {
              // Or just display it.
              displayImageByFileURL(entry);
            }
        },
        function (error) {
            console.log("download error source " + error.source);
            console.log("download error target " + error.target);
            console.log("upload error code" + error.code);
        },
        null, // or, pass false
        {
            //headers: {
            //    "Authorization": "Basic dGVzdHVzZXJuYW1lOnRlc3RwYXNzd29yZA=="
            //}
        }
    );
}

If you just need to display the image, take the FileEntry to call its toURL() function.

function displayImageByFileURL(fileEntry) {
    var elem = document.getElementById('imageElement');
    elem.src = fileEntry.toURL();
}

Depending on your app requirements, you may want to read the file. To support operations with binary files, FileReader supports two methods, readAsBinaryString and readAsArrayBuffer. In this example, use readAsArrayBuffer and pass the FileEntry object to the method. Once you read the file successfully, construct a Blob object using the result of the read.

function readBinaryFile(fileEntry) {
    fileEntry.file(function (file) {
        var reader = new FileReader();

        reader.onloadend = function() {

            console.log("Successful file read: " + this.result);
            // displayFileData(fileEntry.fullPath + ": " + this.result);

            var blob = new Blob([new Uint8Array(this.result)], { type: "image/png" });
            displayImage(blob);
        };

        reader.readAsArrayBuffer(file);

    }, onErrorReadFile);
}

Once you read the file successfully, you can create a DOM URL string using createObjectURL, and then display the image.

function displayImage(blob) {

    // Note: Use window.URL.revokeObjectURL when finished with image.
    var objURL = window.URL.createObjectURL(blob);

    // Displays image if result is a valid DOM string for an image.
    var elem = document.getElementById('imageElement');
    elem.src = objURL;
}

As you saw previously, you can call FileEntry.toURL() instead to just display the downloaded image (skip the file read).

Upload a File

When you upload a File using the File-Transfer plugin, use the File plugin to provide files for upload (again, they must be FileEntry objects). Before you can upload anything, create a file for upload using the getFile method of DirectoryEntry. In this example, create the file in the application’s cache (fs.root). Then call the app’s writeFile function so you have some content to upload.

function onUploadFile() {
    window.requestFileSystem(window.TEMPORARY, 5 * 1024 * 1024, function (fs) {

        console.log('file system open: ' + fs.name);
        var fileName = "uploadSource.txt";
        var dirEntry = fs.root;
        dirEntry.getFile(fileName, { create: true, exclusive: false }, function (fileEntry) {

            // Write something to the file before uploading it.
            writeFile(fileEntry);

        }, onErrorCreateFile);

    }, onErrorLoadFs);
}

In this example, create some simple content, and then call the app’s upload function.

function writeFile(fileEntry, dataObj) {
    // Create a FileWriter object for our FileEntry (log.txt).
    fileEntry.createWriter(function (fileWriter) {

        fileWriter.onwriteend = function () {
            console.log("Successful file write...");
            upload(fileEntry);
        };

        fileWriter.onerror = function (e) {
            console.log("Failed file write: " + e.toString());
        };

        if (!dataObj) {
          dataObj = new Blob(['file data to upload'], { type: 'text/plain' });
        }

        fileWriter.write(dataObj);
    });
}

Forward the FileEntry object to the upload function. To perform the actual upload, use the upload function of the FileTransfer object.

function upload(fileEntry) {
    // !! Assumes variable fileURL contains a valid URL to a text file on the device,
    var fileURL = fileEntry.toURL();

    var success = function (r) {
        console.log("Successful upload...");
        console.log("Code = " + r.responseCode);
        // displayFileData(fileEntry.fullPath + " (content uploaded to server)");
    }

    var fail = function (error) {
        alert("An error has occurred: Code = " + error.code);
    }

    var options = new FileUploadOptions();
    options.fileKey = "file";
    options.fileName = fileURL.substr(fileURL.lastIndexOf('/') + 1);
    options.mimeType = "text/plain";

    var params = {};
    params.value1 = "test";
    params.value2 = "param";

    options.params = params;

    var ft = new FileTransfer();
    // SERVER must be a URL that can handle the request, like
    // http://some.server.com/upload.php
    ft.upload(fileURL, encodeURI(SERVER), success, fail, options);
};

Download the uploaded file

To download the image you just uploaded, you will need a valid URL that can handle the request, for example, http://some.server.com/download.php. Again, the success handler for the FileTransfer.download method receives a FileEntry object. The main difference here from previous examples is that we call FileReader.readAsText to read the result of the download operation, because we uploaded a file with text content.

function download(fileEntry, uri) {

    var fileTransfer = new FileTransfer();
    var fileURL = fileEntry.toURL();

    fileTransfer.download(
        uri,
        fileURL,
        function (entry) {
            console.log("Successful download...");
            console.log("download complete: " + entry.toURL());
            readFile(entry);
        },
        function (error) {
            console.log("download error source " + error.source);
            console.log("download error target " + error.target);
            console.log("upload error code" + error.code);
        },
        null, // or, pass false
        {
            //headers: {
            //    "Authorization": "Basic dGVzdHVzZXJuYW1lOnRlc3RwYXNzd29yZA=="
            //}
        }
    );
}

In the readFile function, call the readAsText method of the FileReader object.

function readFile(fileEntry) {
    fileEntry.file(function (file) {
        var reader = new FileReader();

        reader.onloadend = function () {

            console.log("Successful file read: " + this.result);
            // displayFileData(fileEntry.fullPath + ": " + this.result);

        };

        reader.readAsText(file);

    }, onErrorReadFile);
}