FileSystemDirectoryEntry: getFile() method

The FileSystemDirectoryEntry interface's method getFile() returns a FileSystemFileEntry object corresponding to a file contained somewhere within the directory subtree rooted at the directory on which it's called.

Syntax

getFile()
getFile(path)
getFile(path, options)
getFile(path, options, successCallback)
getFile(path, options, successCallback, errorCallback)

Parameters

path Optional: A string specifying the path, relative to the directory on which the method is called, describing which file's entry to return.
options Optional: An object which allows you to specify whether or not to create the entry if it's missing and if it's an error if the file already exists. These options are currently not useful in Web contexts. See the options parameter section for more details.
successCallback Optional: A method to be called once the FileSystemFileEntry has been created. The method receives a single parameter: the FileSystemFileEntry object representing the file in question.
errorCallback Optional: A method to be called if an error occurs. Receives as its sole input parameter a DOMException object describing the error which occurred.

`options` parameter

The options parameter object accepts the following parameters:

create Optional: If this property is true, and the requested file doesn't exist, the user agent should create it. The default is false. The parent directory must already exist.
exclusive Optional: If true, and the create option is also true, the file must not exist prior to issuing the call. Instead, it must be possible for it to be created newly at call time. The default is false. This parameter is ignored if create is false.

The table below describes the result of each possible combination of these flags depending on whether or not the target file path already exists.

`create` option	`exclusive` option	Path condition	Result
`false`	Ignored	Path exists and is a file	The `successCallback` is called with a `FileSystemFileEntry`.
`false`	Ignored	Path exists but is a directory	The `errorCallback` is called with an appropriate error code (if the callback was provided).
`true`	`false`	Path exists	The existing file is removed and replaced with a new one, then the `successCallback` is called with a `FileSystemFileEntry`.
`true`	`false`	Path doesn't exist	The file is created, then a `FileSystemFileEntry` is passed to the `successCallback`.
`true`	`true`	Path exists	The `errorCallback` is called with an appropriate error, such as `FileError.PATH_EXISTS_ERR`.
`true`	`true`	Path doesn't exist	The file is created, then a `FileSystemFileEntry` is passed to the `successCallback`.

Return value

None (undefined).

Exceptions

NotFoundError DOMException: Thrown if the create option was not specified (or was specified as false), and the file doesn't exist.
SecurityError DOMException: Thrown if the request to access the file was denied for security reasons.
TypeMismatchError DOMException: Thrown if the path specified is not a file; it's probably a directory, but might be an unsupported file descriptor such as a pipe; this depends on the user agent to some extent.

Examples

In this example, a function is presented whose job it is to locate within a user's app data directory a JSON file containing a user dictionary for a specified language, then load that dictionary.

let dictionary = null;

function loadDictionaryForLanguage(appDataDirEntry, lang) {
  dictionary = null;

  appDataDirEntry.getDirectory("Dictionaries", {}, (dirEntry) => {
    dirEntry.getFile(`${lang}-dict.json`, {}, (fileEntry) => {
      fileEntry.file((dictFile) => {
        let reader = new FileReader();

        reader.addEventListener("loadend", () => {
          dictionary = JSON.parse(reader.result);
        });

        reader.readAsText(dictFile);
      });
    });
  });
}

The loadDictionaryForLanguage() function starts by using getDirectory() to obtain the FileSystemDirectoryEntry object representing a subfolder named "Dictionaries" located inside the specified app data directory. The success callback for this takes the resulting directory entry object and calls getFile() to get a FileSystemFileEntry object representing the dictionary file; the success callback for this, in turn, creates a new FileReader and uses it to load the contents of the file. When that is loaded successfully (as indicated by the loadend event being fired), the loaded text is passed into JSON.parse() to be reconstituted into a JavaScript object.

Specifications

Specification
File and Directory Entries API # dom-filesystemdirectoryentry-getfile

Browser compatibility

BCD tables only load in the browser

options parameter

`options` parameter