Entry

La interfaz de acceso de la FileSystem API representa una entrada al sistema de archivos. La entrada puede ser un archivo o directorio. La interfaz incluye métodos para trabajar con archivos- incluyendo copiado, movimiento, eliminacion y lectura de archivos- así como información del archivo al cual apunta- incluyendo su nombre y la ruta desde la raíz hasta la entrada.

Sobre este documento

Este documento fue actualizado por última vez en Marzo 2 de 2011 y trata las especificaciones W3C(Borrador en desarrollo) bocetado en Abril 19 de 2011.

La especificacion está mas o menos abandonada al no haber conseguido tracción significativa.

Conceptos Básicos

The Entry interface includes methods that you would expect for manipulating files and directories, but it also include a really handy method for getting a URL of the entry: toURL(). It also introduces a new URL scheme: filesystem:.

You can use the filesystem: scheme on Google Chrome to see all the files and folders that are stored in the origin of your app. Just use filesystem: scheme for the root directory of the origin of the app. For example, if your app is in https://ww.html5rocks.com, open filesystem:https://www.html5rocks.com/temporary/ in a tab. Chrome shows a read-only list of all the files and folders stored the origin of your app.

Example

To see an example of how toURL() works, see the method description. The snippet below shows you how you can remove a file by name.

// Taking care of the browser-specific prefixes.
window.requestFileSystem  = window.requestFileSystem || window.webkitRequestFileSystem; 

...

// Opening a file system with temporary storage
window.requestFileSystem(TEMPORARY, 1024*1024 /*1MB*/, function(fs) {
  fs.root.getFile('log.txt', {}, function(fileEntry) {
    
    fileEntry.remove(function() {
      console.log('File removed.');
    }, onError);
  
  }, onError);
}, onError); 

Method overview

Attributes

Methods

getMetadata()

Look up last modification date of the entry.

void getMetadata (
  in MetadataCallback ErrorCallback
);

Parameter

successCallback

A callback that is called with the time of the last modification.

errorCallback

A callback that is called when errors happen.

Returns

void

moveTo()

Move an entry to a different location on the file system. Moving a file over an existing file replaces that existing file. A move of a directory on top of an existing empty directory replaces that directory.

You can also use this method for renaming files. You can keep it in the same location and then define the newName parameter.

You cannot do the following:

• Move a directory inside itself or to any child at any depth
• Move an entry into its parent if a name different from its current one isn't provided
• Move a file to a path occupied by a directory or move a directory to a path occupied by a file
• Move any element to a path occupied by a directory that is not empty.

void moveTo (
  in DirectoryEntry parent, optional DOMString newName, optional EntryCallback successCallback, optional ErrorCallback errorCallback
);

Parameter

parent

The directory to which to move the entry.

newName

The new name of the entry. If you do not specify a name, the browser preserves the entry's current name.

successCallback

A callback that is called when the file or directory has been successfully moved.

errorCallback

An optional callback that is called only when errors happen.

Returns

void

copyTo()

Copy an entry to a different location on the file system. You cannot copy an entry inside itself if it is a directory, nor can you copy it into its parent if you don't provide a new name. Directory copies are always recursive—that is, they copy all contents of the directory. You cannot change this behavior. Files are simply duplicated.

void copyTo (
  in DirectoryEntry parent, optional DOMString newName, optional EntryCallback successCallback, optional ErrorCallback errorCallback
);

Parameter

parent

The directory where you want the entry to move to.

newName

The new name of the entry. If you do not specify a name, the browser preserves the entry's current name.

successCallback

A callback that is called when the file or directory has been successfully copied.

errorCallback

An optional callback that is called only when errors happen.

Returns

void

toURL()

Returns a URL that can be used to identify this entry. It exposes a new URL scheme—filesystem:—that you can use to fill src or href attributes. For example, if you wanted to display an image and have its fileEntry, calling toURL() gives you the image file's file system URL. You get something like: filesystem:https://example.com/temporary/lolcat.png.

The following is an example:

var img = document.createElement('img'); 
// Get the URL of the entry, which returns: filesystem:https://example.com/temporary/lolcat.png 
img.src = fileEntry.toURL(); 
document.body.appendChild(img);

The file system URL does not expire. Because the method describes a location on disk, the URL is valid for as long as that location exists. You can delete the file and recreate it, and it's all good.

You can supply the mimeType to simulate the optional MIME-type header associated with HTTP downloads.

DOMString toURL (
  in optional DOMString mimeType
);

Parameter

mimeType

The MIME type that you want to be used to interpret the file when it is loaded through this URL.

Returns

DOMString

remove()

Deletes a file or directory. You cannot delete an empty directory or the root directory of a file system. If you want to remove an empty directory, use removeRecursively() instead.

void remove (
  in VoidCallback successCallback, optional ErrorCallback errorCallback
);

Parameter

successCallback

A callback that is called when the file is successfully deleted.

errorCallback

An optional callback that is called only when errors happen.

Returns

void

getParent()

Look up the parent DirectoryEntry containing the entry. If this entry is the root of its file system, then the parent is itself.

void getParent (
 in EntryCallback successCallback, optional ErrorCallback errorCallback
);

Parameter

parent

The directory where you want to move the entry.

newName

The new name of the entry. If you do not specify a name, the browser preserves the entry's current name.

successCallback

A callback that is called when the look-up entry is successful.

errorCallback

An optional callback that is called when errors happen.

Returns

void

Browser compatibility

See also

• Specification: File API: Directories and System SpecificationWD
• Reference: File System API
• Introduction: Basic Concepts About the File System API