cordova-plugin-file

Introduction

Cordova Plugin File is a plugin that provides a set of file system APIs for handling directories and files on the device. It allows developers to read, write, append, delete, and transfer files within the device’s file system.

Installation

To install the Cordova Plugin File, follow these steps:

1. Navigate to the root folder of your Cordova project in your terminal or command prompt.
2. Run the following command:

cordova plugin add cordova-plugin-file

Usage

File System Initialization

Before using any of the file system APIs, it’s crucial to ensure that the file system is properly initialized:

document.addEventListener('deviceready', onDeviceReady, false);

function onDeviceReady() {
    window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onFileSystemSuccess, onError);
}

function onFileSystemSuccess(fileSystem) {
    /* File system is now ready for use */
}

function onError(error) {
    /* Handle initialization error */
}

Creating a Directory

To create a directory in the file system:

window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onResolveSuccess, onError);

function onResolveSuccess(directoryEntry) {
    directoryEntry.getDirectory('NewDirectory', { create: true }, onDirectoryCreateSuccess, onError);
}

function onDirectoryCreateSuccess(newDirectory) {
    /* New directory created successfully */
}

Creating a File

To create a file within the file system:

window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onResolveSuccess, onError);

function onResolveSuccess(directoryEntry) {
    directoryEntry.getFile('NewFile.txt', { create: true, exclusive: true }, onFileCreateSuccess, onError);
}

function onFileCreateSuccess(fileEntry) {
    /* New file created successfully */
}

Writing to a File

To write content to a file:

window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onResolveSuccess, onError);

function onResolveSuccess(directoryEntry) {
    directoryEntry.getFile('ExistingFile.txt', { create: true }, onFileCreateSuccess, onError);
}

function onFileCreateSuccess(fileEntry) {
    fileEntry.createWriter(onFileWriterSuccess, onError);
}

function onFileWriterSuccess(writer) {
    writer.onwrite = function() {
        /* Content written to the file successfully */
    };

    writer.write('Hello, World!');
}

Reading from a File

To read the content of a file:

window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onResolveSuccess, onError);

function onResolveSuccess(directoryEntry) {
    directoryEntry.getFile('ExistingFile.txt', { create: false }, onFileGetSuccess, onError);
}

function onFileGetSuccess(fileEntry) {
    fileEntry.file(onFileReadSuccess, onError);
}

function onFileReadSuccess(file) {
    var reader = new FileReader();

    reader.onloadend = function() {
        var content = this.result;
        /* Use the content of the file */
    };

    reader.readAsText(file);
}

Deleting a File

To delete a file:

window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onResolveSuccess, onError);

function onResolveSuccess(directoryEntry) {
    directoryEntry.getFile('FileToDelete.txt', { create: false }, onFileGetSuccess, onError);
}

function onFileGetSuccess(fileEntry) {
    fileEntry.remove(onFileRemoveSuccess, onError);
}

function onFileRemoveSuccess() {
    /* File deleted successfully */
}

Transferring a File

To transfer a file from the device’s file system to another location (e.g., remote server or Cordova File Transfer plugin):

window.resolveLocalFileSystemURL(cordova.file.externalDataDirectory, onResolveSuccess, onError);

function onResolveSuccess(directoryEntry) {
    directoryEntry.getFile('FileToTransfer.txt', { create: false }, onFileGetSuccess, onError);
}

function onFileGetSuccess(fileEntry) {
    var fileTransfer = new FileTransfer();

    fileTransfer.upload(fileEntry.toURL(), 'http://example.com/upload', onFileTransferSuccess, onError);
}

function onFileTransferSuccess() {
    /* File transferred successfully */
}

Conclusion

Cordova Plugin File provides a powerful set of APIs for managing files and directories on the device’s file system. By using these APIs, developers can easily manipulate files, create directories, write and read content, delete files, and even transfer them to external locations. This plugin is essential for any Cordova app that requires file system interactions.