Question

I want to get data (audiofiles) from an Amazon S3 server,
and store it in the native filesystem of the portable device.

I will use PhoneGap (PhoneGap – Wiki – Filesystem) to store the data,
but how do I make the GET request and handle the returned file and save it to the filesystem?

Answer 1

The following set of functions might help:

function onDeviceReady() {
    console.log("device is ready");
    window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, gotFS, fail);
}

function fail() {
    console.log("failed to get filesystem");
}

function gotFS(fileSystem) {
    console.log("got filesystem");

    // for later use
    window.fileSystem = fileSystem;

    // Create your app specific dir here
    fileSystem.root.getDirectory(".myapp", {
        create: true,
        exclusive: false
    },
    dirReady, fail);
}

function dirReady(entry) {
    // for later use
    window.appRootDir = entry;
    console.log(JSON.stringify(window.appRootDir));

    var fileToDownload = "http://....";
    var fileName = "file name";
    downloadToAppRoot(fileToDownload, fileName,
    function() {},
    function() {});
}

function downloadToAppRoot(url, name, success, failure) {
    var fileTransfer = new FileTransfer();
    var filePath = window.appRootDir.fullPath + "/" +  name;
    fileTransfer.download(
    url,
    filePath,
    function(entry) {
        console.log("download complete: " + entry.fullPath);
        success(entry);
    },
    function(error) {
        console.log("download error source " + error.source);
        if (failure) failure(error);
    }
    );
}

PhoneGap has extensive File system API to create Directories and Files.
For more details you can check the PhoneGap doc here