Kev*_*Moe 5 javascript google-chrome-os html5-filesystem
我正在尝试为我的HTML5视频播放器添加离线功能.我试图将文件作为blob写入chrome文件系统,然后从那里读取它们.我相信我遇到的问题是文件实际上并没有被写入,只是文件名.由于我的下面的代码目前已经构成,它仍然有效,但仍然只有它永久连接到互联网.我的目标是将文件下载到文件系统中的永久目录,然后在互联网断开连接时继续播放.
$(document).ready(function() {
var dir = "http://www.kevmoe.com/networks/gsplayer/";
var fileextension = ".mp4";
var srcfiles = $.ajax({
//This will retrieve the contents of the folder if the folder is configured as 'browsable'
url: dir,
success: function(data) {
//List all .mp4 file names in the page
$(data).find("a:contains(" + fileextension + ")").each(function() {
var filename = $(this).attr("href").replace(window.location.host, "").replace("http://", "");
$("#container").append("<div id='div1' class='video'><video id='video1' class='vidarray' preload='none' poster='bkg.png'><source src='" + filename + "' type='video/mp4'></video></div>");
async: false;
window.requestFileSystem = window.requestFileSystem || window.webkitRequestFileSystem;
window.requestFileSystem(window.PERSISTANT, 200000 * 1024 * 1024, initFS, errorHandler);
function initFS(fs) {
console.log('filesystem engaged'); // Just to check if everything is OK :)
// place the functions you will learn bellow here
function errorHandler(err) {
var msg = 'An error occured: ';
};
function createDir(rootDir, folders) {
rootDir.getDirectory(folders[0], {
create: true
}, function(dirEntry) {
if (folders.length) {
createDir(dirEntry, folders.slice(1));
}
}, errorHandler);
};
createDir(fs.root, 'files/video/'.split('/'));
fs.root.getDirectory('video', {}, function(dirEntry) {
var dirReader = dirEntry.createReader();
dirReader.readEntries(function(entries) {
for (var i = 0; i < entries.length; i++) {
var entry = entries[i];
if (entry.isDirectory) {
console.log('Directory: ' + entry.fullPath);
} else if (entry.isFile) {
console.log('File: ' + entry.fullPath);
}
}
}, errorHandler);
}, errorHandler);
fs.root.getFile(filename, {
create: true,
exclusive: true
}, function(fileEntry) {
fileEntry.createWriter(function(fileWriter) {
var blob = new Blob([data], {
type: 'video/mp4'
});
fileWriter.write(blob);
}, errorHandler);
console.log('file downloaded');
}, errorHandler);
//Try to add an event listener for when all files are finished loading into file system. Then use another function to source the videos locally.
var dirReader = fs.root.createReader();
var entries = [];
// Call the reader.readEntries() until no more results are returned.
dirReader.readEntries(function(results) {
//List all .mp4 file names in the page
$(results).find("a:contains(" + fileextension + ")").each(function() {
var filename = $(this).attr("href").replace(window.location.host, "").replace("http://", "");
$("#container").append("<div id='div1' class='video'><video id='video1' class='vidarray' preload='none' poster='bkg.png'><source src='" + filename + "' type='video/mp4'></video></div>");
async: false;
}, errorHandler);
});
};
function errorHandler() {
console.log('An error occured');
};
});
var videos = $('.video');
//handle ending of video
videos.find('video').on('ended', function() {
playNextVideo(videos);
});
// start with the first one
playNextVideo(videos);
function playNextVideo(videoList) {
var activeVideo = videoList.filter('.active').removeClass('active'), // identify active video and remove active class
activeIndex = videoList.index(activeVideo), // get the active video index in the group
nextVideo = videoList.eq(activeIndex + 1), // get the next video in line
actualVideo;
// if there is no next video start from first
if (nextVideo.length == 0) nextVideo = videoList.first();
// pause all videos
videoList.find('video').each(function() {
this.pause();
})
// get reference to next video element
actualVideo = nextVideo.find('video').get(0);
// add active class to next video
nextVideo.addClass('active');
// load and play
actualVideo.volume = 0.04;
actualVideo.load();
actualVideo.play();
}
}
});
});
filesystem:协议存储参考与document请求相同的来源的文件LocalFileSystem。也就是说，如果问题处的 JavaScript 是在例如 处创建的，http://example.org则 的路径LocalFileSystem应与 相同http://example.org，而不是file:协议。
如果您尝试存储文件或文件夹以便通过file:协议脱机访问，您可以创建一个.html文档用作模板书签。
.html在线访问一次本地文件以获取文件并填充LocalFileSystem。如果navigator.onLine是true，则导航到http://example.org，否则获取并处理存储在 的文件和文件夹LocalFileSystem。
创建一个列表JSON或 JavaScriptArray来存储要获取的文件列表，而不是解析.html document文件位置。
将本地文件存储为书签。启动 Chromium、Chrome，并设置标志以从协议--allow-file-access-from-files访问协议和在协议处访问协议（如果不在线）。filesystem:file:file:filesystem:
<!DOCTYPE html>
<html>
<head>
<title>LocalFileSystem Offline Videos Bookmark</title>
</head>
<body>
<script>
// location to visit if online
const onLineURL = "https://lorempixel.com/"
+ window.innerWidth
+ "/"
+ window.innerHeight + "/cats";
const props = {
requestedBytes: 1024 * 1024 * 20000,
folder: "videos",
// list of files to fetch for offline viewing
mediaList: [
"http://mirrors.creativecommons.org/movingimages/webm/"
+ "ScienceCommonsJesseDylan_240p.webm"
, "https://nickdesaulniers.github.io/netfix/demo/frag_bunny.mp4"
]
};
let grantedBytes = 0;
function getLocalFileSystem ({requestedBytes = 0, mediaList=[], folder = ""}) {
if (!requestedBytes || !mediaList.length || !folder) {
throw new Error("requestedBytes: Number"
+ " or mediaList: Array"
+ " or folder: String not defined");
};
// do stuff with `filesystem:` URL
function processLocalFilePath(localPath) {
const video = document.createElement("video");
document.body.appendChild(video);
video.controls = true;
video.src = localPath;
}
function errorHandler(err) {
console.log(err);
}
function writeFile(dir, fn, fp, localPath) {
console.log(dir, fn, fp, localPath);
dir.getFile(fn, {}, function(fileEntry) {
fileEntry.createWriter(function(fileWriter) {
fileWriter.onwriteend = function(e) {
// do stuff when file is written
console.log(e.type, localPath + " written");
window.webkitResolveLocalFileSystemURL(localPath
, function(file) {
// file exists in LocalFileSystem
processLocalFilePath(localPath);
}, errorHandler)
};
fileWriter.onerror = errorHandler;
fetch(fp).then(function(response) {
return response.blob()
}).then(function(blob) {
fileWriter.write(blob);
}).catch(errorHandler)
}, errorHandler);
}, errorHandler);
}
if (mediaList && mediaList.length) {
navigator.webkitTemporaryStorage.requestQuota(requestedBytes
, function(grantedBytes_) {
grantedBytes = grantedBytes_;
console.log("Requested bytes:", requestedBytes
, "Granted bytes:", grantedBytes);
window.webkitRequestFileSystem(window.TEMPORARY
, grantedBytes
, function(fs) {
const url = fs.root.toURL();
mediaList.forEach(function(filename) {
const localPath = url + folder + "/"
+ filename.split("/").pop();
window.webkitResolveLocalFileSystemURL(localPath
, function(file) {
// file exists in LocalFileSystem
console.log(localPath + " exists at LocalFileSystem");
processLocalFilePath(localPath)
}, function(err) {
console.log(err, localPath
+ " not found in LocalFileSystem");
// Exception is thrown if file
// or folder path not found
// create `folder` directory, get files
fs.root.getDirectory(folder, {}
, function(dir) {
writeFile(dir
, filename.split("/").pop()
, filename
, localPath);
}),
errorHandler
})
})
})
}, errorHandler)
}
}
if (location.href !== onLineURL && navigator.onLine) {
location.href = onLineURL;
} else {
getLocalFileSystem(props);
}
</script>
</body>
</html>
也可以看看
另一种方法可能是利用ServiceWorker