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
FileSystemSync requestFileSystemSync (in unsigned short type, in long long size) raises FileException; |
EntrySync resolveLocalFileSystemSyncURL (in DOMString url) raises FileException; |
Constants
Constant | Value | Description |
---|---|---|
TEMPORARY |
0 |
Transient storage that can be be removed by the browser at its discretion. |
PERSISTENT |
1 |
Storage that stays in the browser unless the user or the app expunges it. |
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
orPERSISTENT
. - 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:
Exception | Description |
---|---|
SECURITY_ERROR |
The application does not have permission to access the file system interface. For example, you cannot run from file:// . For more details, see the article on basic concepts. |
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:
Exception | Description |
---|---|
ENCODING_ERR |
The syntax of the URL was invalid. |
NOT_FOUND_ERR |
The URL was structurally correct, but refers to a resource that does not exist. |
SECURITY_ERR |
The application does not have permission to access the file system interface. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
LocalFileSystemSync | Chrome
Full support
13
| Edge ? | Firefox No support No | IE No support No | Opera No support No | Safari No support No | WebView Android
Full support
Yes
| Chrome Android
Full support
Yes
| Firefox Android No support No | Opera Android No support No | Safari iOS No support No | Samsung Internet Android ? |
requestFileSystemSync | Chrome Full support 13 | Edge ? | Firefox No support No | IE No support No | Opera No support No | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android No support No | Opera Android No support No | Safari iOS No support No | Samsung Internet Android ? |
resolveLocalFileSystemSyncURL | Chrome Full support 13 | Edge ? | Firefox No support No | IE No support No | Opera No support No | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android No support No | Opera Android No support No | Safari iOS No support No | Samsung Internet Android ? |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Non-standard. Expect poor cross-browser support.
- Non-standard. Expect poor cross-browser support.
- Requires a vendor prefix or different name for use.
- Requires a vendor prefix or different name for use.
See also
Specification:File API: Directories and System SpecificationWD
Reference: File System API
Introduction: Basic Concepts About the File System API