chrome.fileSystemProvider

Description: Use the chrome.fileSystemProvider API to create file systems, that can be accessible from the file manager on Chrome OS.
Availability: Since Chrome 40.
Permissions: "fileSystemProvider"

Important: This API works only on Chrome OS.

Manifest

You must declare the "fileSystemProvider" permission and section in the extension manifest to use the File System Provider API. For example:

      {
        "name": "My app",
        ...
        "permissions": [
          "fileSystemProvider"
        ],
        ...
        "file_system_provider_capabilities": {
          "configurable": true,
          "watchable": false,
          "multiple_mounts": true,
          "source": "network"
        },
        ...
      }

The file_system_provider section must be declared as follows:

  • configurable (boolean) - optional

    Whether configuring via onConfigureRequested is supported. By default: false.

  • multiple_mounts (boolean) - optional

    Whether multiple (more than one) mounted file systems are supported. By default: false.

  • watchable (boolean) - optional

    Whether setting watchers and notifying about changes is supported. By default: false.

  • source (enum of "file", "device", or "network") - required

    Source of data for mounted file systems.

Files app uses above information in order to render related UI elements approprietly. For example, if configurable is set to true, then a menu item for configuring volumes will be rendered. Similarly, if multiple_mounts is set to true, then Files app will allow to add more than one mount points from the UI. If watchable is false, then a refresh button will be rendered. Note, that if possible you should add support for watchers, so changes on the file system can be reflected immediately and automatically.

Overview

File System Provider API allows extensions to support virtual file systems, which are available in the file manager on Chrome OS. Use cases include decompressing archives and accessing files in a cloud service other than Drive.

Mounting file systems

Providing extensions can either provide file system contents from an external source (such as a remote server or a USB device), or using a local file (such as an archive) as its input.

For file handlers, the providing extension should have a file_handlers manifest entry in order to be launched when the file is selected in the file manager. When the extension is executed with a file to be handled, it has to mount a file system and start serving contents from the provided file.

If the source is network or a device, then the file system should be mounted when onMountRequested event is called.

Source of the file system data Entry point
"file" app.runtime.onLaunched
"device" or "network" onMountRequested

Configuring file systems

Provided file systems once mounted can be configured via the onConfigureRequested event. It's especially useful for file systems which provide contents via network in order to set proper credentials. Handling this event is optional.

Life cycle

Provided file systems once mounted are remembered by Chrome and remounted automatically after reboot or restart. Hence, once a file system is mounted by a providing extension, it will stay until either the extension is unloaded, or the extension calls the unmount method.

In case of acting as a file handler, the handled file may need to be stored to access it after either a reboot, or suspending and resuming an event page of the providing extension. In such case fileSystem.retainEntry and fileSystem.restoreEntry should be used.

Summary

Types
ProviderError
OpenFileMode
ChangeType
CommonActionId
EntryMetadata
FileSystemInfo
Methods
mount − chrome.fileSystemProvider.mount(object options, function callback)
unmount − chrome.fileSystemProvider.unmount(object options, function callback)
getAll − chrome.fileSystemProvider.getAll(function callback)
get − chrome.fileSystemProvider.get(string fileSystemId, function callback)
notify − chrome.fileSystemProvider.notify(object options, function callback)
Events
onUnmountRequested
onGetMetadataRequested
onGetActionsRequested
onReadDirectoryRequested
onOpenFileRequested
onCloseFileRequested
onReadFileRequested
onCreateDirectoryRequested
onDeleteEntryRequested
onCreateFileRequested
onCopyEntryRequested
onMoveEntryRequested
onTruncateRequested
onWriteFileRequested
onAbortRequested
onConfigureRequested
onMountRequested
onAddWatcherRequested
onRemoveWatcherRequested
onExecuteActionRequested

Types

ProviderError

Error codes used by providing extensions in response to requests as well as in case of errors when calling methods of the API. For success, "OK" must be used.
Enum
"OK", "FAILED", "IN_USE", "EXISTS", "NOT_FOUND", "ACCESS_DENIED", "TOO_MANY_OPENED", "NO_MEMORY", "NO_SPACE", "NOT_A_DIRECTORY", "INVALID_OPERATION", "SECURITY", "ABORT", "NOT_A_FILE", "NOT_EMPTY", "INVALID_URL", or "IO"

OpenFileMode

Mode of opening a file. Used by onOpenFileRequested.
Enum
"READ", or "WRITE"

ChangeType

Type of a change detected on the observed directory.
Enum
"CHANGED", or "DELETED"

CommonActionId

List of common actions. "SHARE" is for sharing files with others. "SAVE_FOR_OFFLINE" for pinning (saving for offline access). "OFFLINE_NOT_NECESSARY" for notifying that the file doesn't need to be stored for offline access anymore. Used by onGetActionsRequested and onExecuteActionRequested.
Enum
"SAVE_FOR_OFFLINE", "OFFLINE_NOT_NECESSARY", or "SHARE"

EntryMetadata

properties
boolean (optional) isDirectory

True if it is a directory. Must be provided if requested in options.

string (optional) name

Name of this entry (not full path name). Must not contain '/'. For root it must be empty. Must be provided if requested in options.

double (optional) size

File size in bytes. Must be provided if requested in options.

Date (optional) modificationTime

The last modified time of this entry. Must be provided if requested in options.

string (optional) mimeType

Mime type for the entry. Always optional, but should be provided if requested in options.

string (optional) thumbnail

Thumbnail image as a data URI in either PNG, JPEG or WEBP format, at most 32 KB in size. Optional, but can be provided only when explicitly requested by the onGetMetadataRequested event.

FileSystemInfo

properties
string fileSystemId

The identifier of the file system.

string displayName

A human-readable name for the file system.

boolean writable

Whether the file system supports operations which may change contents of the file system (such as creating, deleting or writing to files).

integer openedFilesLimit

Since Chrome 42.

The maximum number of files that can be opened at once. If 0, then not limited.

array of object openedFiles

Since Chrome 42.

List of currently opened files.

Properties of each object

integer openRequestId

A request ID to be be used by consecutive read/write and close requests.

string filePath

The path of the opened file.

OpenFileMode mode

Whether the file was opened for reading or writing.

boolean (optional) supportsNotifyTag

Since Chrome 45.

Whether the file system supports the tag field for observing directories.

array of object watchers

Since Chrome 45.

List of watchers.

Properties of each object

string entryPath

The path of the entry being observed.

boolean recursive

Whether watching should include all child entries recursively. It can be true for directories only.

string (optional) lastTag

Tag used by the last notification for the watcher.

Methods

mount

chrome.fileSystemProvider.mount(object options, function callback)

Mounts a file system with the given fileSystemId and displayName. displayName will be shown in the left panel of the Files app. displayName can contain any characters including '/', but cannot be an empty string. displayName must be descriptive but doesn't have to be unique. The fileSystemId must not be an empty string.

Depending on the type of the file system being mounted, the source option must be set appropriately.

In case of an error, runtime.lastError will be set with a corresponding error code.

Parameters
object options
string fileSystemId

The string indentifier of the file system. Must be unique per each extension.

string displayName

A human-readable name for the file system.

boolean (optional) writable

Whether the file system supports operations which may change contents of the file system (such as creating, deleting or writing to files).

integer (optional) openedFilesLimit

Since Chrome 41.

The maximum number of files that can be opened at once. If not specified, or 0, then not limited.

boolean (optional) supportsNotifyTag

Since Chrome 45.

Whether the file system supports the tag field for observed directories.

boolean (optional) persistent

Since Chrome 64.

Whether the framework should resume the file system at the next sign-in session. True by default.

function (optional) callback

A generic result callback to indicate success or failure.

If you specify the callback parameter, it should be a function that looks like this:

function() {...};

unmount

chrome.fileSystemProvider.unmount(object options, function callback)

Unmounts a file system with the given fileSystemId. It must be called after onUnmountRequested is invoked. Also, the providing extension can decide to perform unmounting if not requested (eg. in case of lost connection, or a file error).

In case of an error, runtime.lastError will be set with a corresponding error code.

Parameters
object options
string fileSystemId

The identifier of the file system to be unmounted.

function (optional) callback

A generic result callback to indicate success or failure.

If you specify the callback parameter, it should be a function that looks like this:

function() {...};

getAll

chrome.fileSystemProvider.getAll(function callback)

Returns all file systems mounted by the extension.

Parameters
function callback

Callback to receive the result of getAll function.

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

function(array of FileSystemInfo fileSystems) {...};
array of FileSystemInfo fileSystems

get

chrome.fileSystemProvider.get(string fileSystemId, function callback)

Since Chrome 42.

Returns information about a file system with the passed fileSystemId.

Parameters
string fileSystemId
function callback

Callback to receive the result of get function.

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

function( FileSystemInfo fileSystem) {...};
FileSystemInfo fileSystem

notify

chrome.fileSystemProvider.notify(object options, function callback)

Since Chrome 45.

Notifies about changes in the watched directory at observedPath in recursive mode. If the file system is mounted with supportsNofityTag, then tag must be provided, and all changes since the last notification always reported, even if the system was shutdown. The last tag can be obtained with getAll.

To use, the file_system_provider.notify manifest option must be set to true.

Value of tag can be any string which is unique per call, so it's possible to identify the last registered notification. Eg. if the providing extension starts after a reboot, and the last registered notification's tag is equal to "123", then it should call notify for all changes which happened since the change tagged as "123". It cannot be an empty string.

Not all providers are able to provide a tag, but if the file system has a changelog, then the tag can be eg. a change number, or a revision number.

Note that if a parent directory is removed, then all descendant entries are also removed, and if they are watched, then the API must be notified about the fact. Also, if a directory is renamed, then all descendant entries are in fact removed, as there is no entry under their original paths anymore.

In case of an error, runtime.lastError will be set will a corresponding error code.

Parameters
object options
string fileSystemId

The identifier of the file system related to this change.

string observedPath

The path of the observed entry.

boolean recursive

Mode of the observed entry.

ChangeType changeType

The type of the change which happened to the observed entry. If it is DELETED, then the observed entry will be automatically removed from the list of observed entries.

array of object (optional) changes

List of changes to entries within the observed directory (including the entry itself)

Properties of each object

string entryPath

The path of the changed entry.

ChangeType changeType

The type of the change which happened to the entry.

string (optional) tag

Tag for the notification. Required if the file system was mounted with the supportsNotifyTag option. Note, that this flag is necessary to provide notifications about changes which changed even when the system was shutdown.

function (optional) callback

A generic result callback to indicate success or failure.

If you specify the callback parameter, it should be a function that looks like this:

function() {...};

Events

onUnmountRequested

Raised when unmounting for the file system with the fileSystemId identifier is requested. In the response, the unmount API method must be called together with successCallback. If unmounting is not possible (eg. due to a pending operation), then errorCallback must be called.

addListener

chrome.fileSystemProvider.onUnmountRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system to be unmounted.

integer requestId

The unique identifier of this request.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onGetMetadataRequested

Raised when metadata of a file or a directory at entryPath is requested. The metadata must be returned with the successCallback call. In case of an error, errorCallback must be called.

addListener

chrome.fileSystemProvider.onGetMetadataRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string entryPath

The path of the entry to fetch metadata about.

boolean isDirectory

Since Chrome 49.

Set to true if is_directory value is requested.

boolean name

Since Chrome 49.

Set to true if name value is requested.

boolean size

Since Chrome 49.

Set to true if size value is requested.

boolean modificationTime

Since Chrome 49.

Set to true if modificationTime value is requested.

boolean mimeType

Since Chrome 49.

Set to true if mimeType value is requested.

boolean thumbnail

Set to true if the thumbnail is requested.

function successCallback

Success callback for the onGetMetadataRequested event.

Parameters
EntryMetadata metadata
function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onGetActionsRequested

Since Chrome 48.

Raised when a list of actions for a set of files or directories at entryPaths is requested. All of the returned actions must be applicable to each entry. If there are no such actions, an empty array should be returned. The actions must be returned with the successCallback call. In case of an error, errorCallback must be called.

addListener

chrome.fileSystemProvider.onGetActionsRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

array of string entryPaths

List of paths of entries for the list of actions.

function successCallback

Success callback for the onGetActionsRequested event.

Parameters
array of object actions

Properties of each object

string id

The identifier of the action. Any string or CommonActionId for common actions.

string (optional) title

The title of the action. It may be ignored for common actions.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onReadDirectoryRequested

Raised when contents of a directory at directoryPath are requested. The results must be returned in chunks by calling the successCallback several times. In case of an error, errorCallback must be called.

addListener

chrome.fileSystemProvider.onReadDirectoryRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string directoryPath

The path of the directory which contents are requested.

boolean isDirectory

Since Chrome 49.

Set to true if is_directory value is requested.

boolean name

Since Chrome 49.

Set to true if name value is requested.

boolean size

Since Chrome 49.

Set to true if size value is requested.

boolean modificationTime

Since Chrome 49.

Set to true if modificationTime value is requested.

boolean mimeType

Since Chrome 49.

Set to true if mimeType value is requested.

boolean thumbnail

Since Chrome 49.

Set to true if the thumbnail is requested.

function successCallback

Success callback for the onReadDirectoryRequested event. If more entries will be returned, then hasMore must be true, and it has to be called again with additional entries. If no more entries are available, then hasMore must be set to false.

Parameters
array of EntryMetadata entries
boolean hasMore
function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onOpenFileRequested

Raised when opening a file at filePath is requested. If the file does not exist, then the operation must fail. Maximum number of files opened at once can be specified with MountOptions.

addListener

chrome.fileSystemProvider.onOpenFileRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

A request ID which will be used by consecutive read/write and close requests.

string filePath

The path of the file to be opened.

OpenFileMode mode

Whether the file will be used for reading or writing.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onCloseFileRequested

Raised when opening a file previously opened with openRequestId is requested to be closed.

addListener

chrome.fileSystemProvider.onCloseFileRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

integer openRequestId

A request ID used to open the file.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onReadFileRequested

Raised when reading contents of a file opened previously with openRequestId is requested. The results must be returned in chunks by calling successCallback several times. In case of an error, errorCallback must be called.

addListener

chrome.fileSystemProvider.onReadFileRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

integer openRequestId

A request ID used to open the file.

double offset

Position in the file (in bytes) to start reading from.

double length

Number of bytes to be returned.

function successCallback

Success callback for the onReadFileRequested event. If more data will be returned, then hasMore must be true, and it has to be called again with additional entries. If no more data is available, then hasMore must be set to false.

Parameters
ArrayBuffer data
boolean hasMore
function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onCreateDirectoryRequested

Raised when creating a directory is requested. The operation must fail with the EXISTS error if the target directory already exists. If recursive is true, then all of the missing directories on the directory path must be created.

addListener

chrome.fileSystemProvider.onCreateDirectoryRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string directoryPath

The path of the directory to be created.

boolean recursive

Whether the operation is recursive (for directories only).

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onDeleteEntryRequested

Raised when deleting an entry is requested. If recursive is true, and the entry is a directory, then all of the entries inside must be recursively deleted as well.

addListener

chrome.fileSystemProvider.onDeleteEntryRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string entryPath

The path of the entry to be deleted.

boolean recursive

Whether the operation is recursive (for directories only).

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onCreateFileRequested

Raised when creating a file is requested. If the file already exists, then errorCallback must be called with the "EXISTS" error code.

addListener

chrome.fileSystemProvider.onCreateFileRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string filePath

The path of the file to be created.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onCopyEntryRequested

Raised when copying an entry (recursively if a directory) is requested. If an error occurs, then errorCallback must be called.

addListener

chrome.fileSystemProvider.onCopyEntryRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string sourcePath

The source path of the entry to be copied.

string targetPath

The destination path for the copy operation.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onMoveEntryRequested

Raised when moving an entry (recursively if a directory) is requested. If an error occurs, then errorCallback must be called.

addListener

chrome.fileSystemProvider.onMoveEntryRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string sourcePath

The source path of the entry to be moved into a new place.

string targetPath

The destination path for the copy operation.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onTruncateRequested

Raised when truncating a file to a desired length is requested. If an error occurs, then errorCallback must be called.

addListener

chrome.fileSystemProvider.onTruncateRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string filePath

The path of the file to be truncated.

double length

Number of bytes to be retained after the operation completes.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onWriteFileRequested

Raised when writing contents to a file opened previously with openRequestId is requested.

addListener

chrome.fileSystemProvider.onWriteFileRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

integer openRequestId

A request ID used to open the file.

double offset

Position in the file (in bytes) to start writing the bytes from.

ArrayBuffer data

Buffer of bytes to be written to the file.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onAbortRequested

Raised when aborting an operation with operationRequestId is requested. The operation executed with operationRequestId must be immediately stopped and successCallback of this abort request executed. If aborting fails, then errorCallback must be called. Note, that callbacks of the aborted operation must not be called, as they will be ignored. Despite calling errorCallback, the request may be forcibly aborted.

addListener

chrome.fileSystemProvider.onAbortRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

integer operationRequestId

An ID of the request to be aborted.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onConfigureRequested

Since Chrome 44.

Raised when showing a configuration dialog for fileSystemId is requested. If it's handled, the file_system_provider.configurable manfiest option must be set to true.

addListener

chrome.fileSystemProvider.onConfigureRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system to be configured.

integer requestId

The unique identifier of this request.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onMountRequested

Since Chrome 44.

Raised when showing a dialog for mounting a new file system is requested. If the extension/app is a file handler, then this event shouldn't be handled. Instead app.runtime.onLaunched should be handled in order to mount new file systems when a file is opened. For multiple mounts, the file_system_provider.multiple_mounts manifest option must be set to true.

addListener

chrome.fileSystemProvider.onMountRequested.addListener(function callback)
Parameters
function callback

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

function(function successCallback, function errorCallback) {...};
function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onAddWatcherRequested

Since Chrome 45.

Raised when setting a new directory watcher is requested. If an error occurs, then errorCallback must be called.

addListener

chrome.fileSystemProvider.onAddWatcherRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string entryPath

The path of the entry to be observed.

boolean recursive

Whether observing should include all child entries recursively. It can be true for directories only.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onRemoveWatcherRequested

Since Chrome 45.

Raised when the watcher should be removed. If an error occurs, then errorCallback must be called.

addListener

chrome.fileSystemProvider.onRemoveWatcherRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

string entryPath

The path of the watched entry.

boolean recursive

Mode of the watcher.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error

onExecuteActionRequested

Since Chrome 48.

Raised when executing an action for a set of files or directories is\ requested. After the action is completed, successCallback must be called. On error, errorCallback must be called.

addListener

chrome.fileSystemProvider.onExecuteActionRequested.addListener(function callback)
Parameters
function callback

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

function(object options, function successCallback, function errorCallback) {...};
object options
string fileSystemId

The identifier of the file system related to this operation.

integer requestId

The unique identifier of this request.

array of string entryPaths

The set of paths of the entries to be used for the action.

string actionId

The identifier of the action to be executed.

function successCallback

Callback to be called by the providing extension in case of a success.

function errorCallback

Callback to be called by the providing extension in case of an error. Any error code is allowed except OK.

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

function( ProviderError error) {...};
ProviderError error