Asynch DL

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Mar 5th, 2012

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JavaScript 3.58 KB | None | 0 0

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<script type="text/javascript" charset="utf-8">
var DATADIR;
var DATA_URL = "http://url_to_file_list/updatedata.php";
var imagePath = "http://path_to_files/";
var imageData = '';
//Loaded file system
function onFSSuccess(fileSystem) {
fileSystem.root.getDirectory("appdata",{create:true},gotDir,onError);
}
//The directory entry callback
function gotDir(d){
console.log("got dir");
DATADIR = d;
var reader = DATADIR.createReader();
reader.readEntries(function(d){
downloadImages();
},onError);
}
function onError(e){
console.log("ERROR");
console.log(JSON.stringify(e));
}
function onDeviceReady() {
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, onFSSuccess, null);
}
function downloadImages(){
$.get(DATA_URL, {}, function(imageList) {
imageData.imageList = imageList;
console.log("Files : "+imageList);
console.log("Start downloading...");
imageData.imagePath = imagePath;
console.Log('Total images to download: ' + imageData.imageList.length);
downloadImage();
}, "json");
}
/* download image syncronously */
function downloadImage(){
if(imageData.imageList.length > 0){
var imageName = imageData.imageList[0];
var imagePath = imageData.imagePath;
console.Log('Start file download: ' + imagePath + imageName);
//check if file exists, pass the function as new closure, so the variable is preserved
DATADIR.getFile(imageName, {create: false}, successImageExists, (function(name, path){
return function(){
failImageExists(name, path)
}
})(imageName, imagePath));
}
}
/* image exists */
function successImageExists(file){
console.Log('Image Exists: ' + file.name);
updateImageDownloadProgress();
}
/* image doesn't exists */
function failImageExists(imageName,imagePath){
console.Log('image does not Exists');
//start download
console.Log('Download Image To: ' + DATADIR.fullPath + '/' + imageName);
ft.download(imagePath + escape(imageName), DATADIR.fullPath + '/' + imageName, onImageDownload, onImageDownloadFail);
}
/* on image download fail */
function onImageDownloadFail(error){
console.Log('image not downloaded. Error: ' + JSON.stringify(error));
updateImageDownloadProgress();
}
/* on image download success */
function onImageDownload(image){
updateImageDownloadProgress();
}
/* update image download progress */
function updateImageDownloadProgress(){
imageData.imageList = imageData.imageList.slice(1);
console.Log('images left to download: ' + imageData.imageList.length);
if(imageData.imageList.length == 0){
imagesDownloaded = true;
} else {
downloadImage();
}
}
function init() {
//document.location='app.html';
document.addEventListener("deviceready", onDeviceReady, true);
}
</script>

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