chrome.fileSystem

Description: Use the chrome.fileSystem API to create, read, navigate, and write to a sandboxed section of the user's local file system. With this API, Chrome Apps can read and write to a user-selected location. For example, a text editor app can use the API to read and write local documents. All failures are notified via chrome.runtime.lastError.
Availability: Stable since Chrome 23.
Permissions: "fileSystem"
{"fileSystem": ["write"]}
{"fileSystem": ["write", "retainEntries", "directory"]}
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Summary

Methods
getDisplayPath − chrome.fileSystem.getDisplayPath(Entry entry, function callback)
getWritableEntry − chrome.fileSystem.getWritableEntry(Entry entry, function callback)
isWritableEntry − chrome.fileSystem.isWritableEntry(Entry entry, function callback)
chooseEntry − chrome.fileSystem.chooseEntry(object options, function callback)
restoreEntry − chrome.fileSystem.restoreEntry(string id, function callback)
isRestorable − chrome.fileSystem.isRestorable(string id, function callback)
retainEntry − string chrome.fileSystem.retainEntry(Entry entry)

Methods

getDisplayPath

chrome.fileSystem.getDisplayPath(Entry entry, function callback)

Get the display path of an Entry object. The display path is based on the full path of the file or directory on the local file system, but may be made more readable for display purposes.

Parameters
Entry entry
function callback

The callback parameter should be a function that looks like this:

function(string displayPath) {...};
string displayPath

getWritableEntry

chrome.fileSystem.getWritableEntry(Entry entry, function callback)

Get a writable Entry from another Entry. This call will fail with a runtime error if the application does not have the 'write' permission under 'fileSystem'. If entry is a DirectoryEntry, this call will fail if the application does not have the 'directory' permission under 'fileSystem'.

Parameters
Entry entry
function callback

The callback parameter should be a function that looks like this:

function(Entry entry) {...};
Entry entry

isWritableEntry

chrome.fileSystem.isWritableEntry(Entry entry, function callback)

Gets whether this Entry is writable or not.

Parameters
Entry entry
function callback

The callback parameter should be a function that looks like this:

function(boolean isWritable) {...};
boolean isWritable

chooseEntry

chrome.fileSystem.chooseEntry(object options, function callback)

Ask the user to choose a file or directory.

Parameters
object (optional) options
enum of "openFile", "openWritableFile", "saveFile", or "openDirectory" (optional) type Type of the prompt to show. The default is 'openFile'.
openFile
Prompts the user to open an existing file and returns a FileEntry on success. From Chrome 31 onwards, the FileEntry will be writable if the application has the 'write' permission under 'fileSystem'; otherwise, the FileEntry will be read-only.
openWritableFile
Prompts the user to open an existing file and returns a writable FileEntry on success. Calls using this type will fail with a runtime error if the application doesn't have the 'write' permission under 'fileSystem'.
saveFile
Prompts the user to open an existing file or a new file and returns a writable FileEntry on success. Calls using this type will fail with a runtime error if the application doesn't have the 'write' permission under 'fileSystem'.
openDirectory
Prompts the user to open a directory and returns a DirectoryEntry on success. Calls using this type will fail with a runtime error if the application doesn't have the 'directory' permission under 'fileSystem'. If the application has the 'write' permission under 'fileSystem', the returned DirectoryEntry will be writable; otherwise it will be read-only. New in Chrome 31.
string (optional) suggestedName The suggested file name that will be presented to the user as the default name to read or write. This is optional.
array of object (optional) accepts The optional list of accept options for this file opener. Each option will be presented as a unique group to the end-user.

Properties of each object

string (optional) description This is the optional text description for this option. If not present, a description will be automatically generated; typically containing an expanded list of valid extensions (e.g. "text/html" may expand to "*.html, *.htm").
array of string (optional) mimeTypes Mime-types to accept, e.g. "image/jpeg" or "audio/*". One of mimeTypes or extensions must contain at least one valid element.
array of string (optional) extensions Extensions to accept, e.g. "jpg", "gif", "crx".
boolean (optional) acceptsAllTypes Whether to accept all file types, in addition to the options specified in the accepts argument. The default is true. If the accepts field is unset or contains no valid entries, this will always be reset to true.
boolean (optional) acceptsMultiple Whether to accept multiple files. This is only supported for openFile and openWritableFile. The callback to chooseEntry will be called with a list of entries if this is set to true. Otherwise it will be called with a single Entry.
function callback

The callback parameter should be a function that looks like this:

function(Entry entry, array of FileEntry fileEntries) {...};
Entry (optional) entry
array of FileEntry (optional) fileEntries

Properties of each object

restoreEntry

chrome.fileSystem.restoreEntry(string id, function callback)

Returns the file entry with the given id if it can be restored. This call will fail with a runtime error otherwise. This method is new in Chrome 31.

Parameters
string id
function callback

The callback parameter should be a function that looks like this:

function(Entry entry) {...};
Entry entry

isRestorable

chrome.fileSystem.isRestorable(string id, function callback)

Returns whether the app has permission to restore the entry with the given id. This method is new in Chrome 31.

Parameters
string id
function callback

The callback parameter should be a function that looks like this:

function(boolean isRestorable) {...};
boolean isRestorable

retainEntry

string chrome.fileSystem.retainEntry(Entry entry)

Returns an id that can be passed to restoreEntry to regain access to a given file entry. Only the 500 most recently used entries are retained, where calls to retainEntry and restoreEntry count as use. If the app has the 'retainEntries' permission under 'fileSystem', entries are retained indefinitely. Otherwise, entries are retained only while the app is running and across restarts. This method is new in Chrome 31.

Parameters
Entry entry