LocalFileSystemSync - Web APIs 编辑

Non-standard

This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The LocalFileSystemSync interface of the File System API gives you access to a sandboxed file system. It is intended to be used with WebWorkers. The methods are implemented by worker objects.

About this document

This document was last updated on March 2, 2012 and follows the W3C Specifications (Working Draft) drafted on April 19, 2011.

This specification is more or less abandonned, failing to get significant traction.

Basic concepts

You can request access to a sandboxed file system by requesting LocalFileSystemSync object from within a web worker. The global methods in the window object requestFileSystemSync() and resolveLocalFileSystemSyncURL() methods are exposed to the Worker's global scope. Calling window.requestFileSystemSync() for creates new storage for your web app.

For more concepts, see the counterpart article for the asynchronous API.

Example

//Taking care of the browser-specific prefix
window.requestFileSystemSync  = window.requestFileSystemSync || window.webkitRequestFileSystemSync;

// The first parameter defines the type of storage: persistent or temporary
// Next, set the size of space needed (in bytes)
// initFs is the success callback
// And the last one is the error callback
// for denial of access and other errors.

var fs = requestFileSystemSync(TEMPORARY, 1024*1024 /*1MB*/);

Because you are using a synchronous API, you don't need success and error callbacks.

Method overview

Constants

Methods

requestFileSystemSync()

Requests a file system where data should be stored. You access a sandboxed file system by requesting a LocalFileSystemSync object from within a web worker using this global method, window.requestFileSystemSync(). [ RESEARCH ]

FileSystemSync requestFileSystemSync(
  in unsigned short type,
  in unsigned long long size
);

Parameters

type

The storage type of the file system. The values can be either TEMPORARY or PERSISTENT.

size

The storage space—in bytes—that you need for your app.

Returns

FileSystemSync

An object that represents the file system.

Exceptions

This method can raise an FileException with the following code:

resolveLocalFileSystemSyncURL()

Allows the user to look up the Entry for a file or directory referred to by a local URL.

void resolveLocalFileSystemURL(
  in DOMString url
);

Parameter

url

The URL of a local file in the file system.

Returns

EntrySync

An object that represents entries in the file system.

Exceptions

This method can raise a FileException with the following codes:

See also

Specification:File API: Directories and System SpecificationWD

Reference: File System API

Introduction: Basic Concepts About the File System API