FileSystemHandle.md

FileSystemHandle

Namespace: SpawnDev.SpawnJS.JSObjects
Inherits: SpawnJSObject
Source: JSObjects/FileSystemHandle.cs
MDN Reference: FileSystemHandle on MDN

The FileSystemHandle interface of the File System API is an object which represents a file or directory entry. Multiple handles can represent the same entry. For the most part you do not work with FileSystemHandle directly but rather its child interfaces FileSystemFileHandle and FileSystemDirectoryHandle. https://developer.mozilla.org/en-US/docs/Web/API/FileSystemHandle

Constructors

Signature	Description
FileSystemHandle(SpawnJSObjectReference _ref)	Deserialization constructor

Properties

Property	Type	Access	Description
Name	string	get	Returns the name of the associated entry.
Kind	string	get	Returns the type of entry. This is 'file' if the associated entry is a file or 'directory'.
FilePermissionsOptions	class	get	Options for requesting file permissions

Methods

Method	Return Type	Description
IsSameEntry(FileSystemHandle fsHandle)	Task<bool>	Compares two handles to see if the associated entries (either a file or directory) match. Multiple handles can represent the same entry, so this is the way to test handle identity.
ResolveType(bool moveJSRef)	FileSystemHandle	Returns a FileSystemDirectoryHandle or FileSystemFileHandle based on the FileSystemHandle.Kind If true, the SpawnJSObjectReference from this SpawnJSObject is moved to the new type instead of copied
ToFileSystemDirectoryHandle(bool moveJSRef)	FileSystemDirectoryHandle?	Returns a FileSystemDirectoryHandle SpawnJSObject for this entry if this entry Kind is directory
ToFileSystemFileHandle(bool moveJSRef)	FileSystemFileHandle?	Returns a FileSystemFileHandle SpawnJSObject for this entry if this entry Kind is file
GetReadWritePermissions()	Task<string>	Returns a string with "r", "rw", or "" indicating read, write permissions
IsWritable()	Task<bool>	Returns true if the FileSystemHandle is writable
IsReadable()	Task<bool>	Returns true if the FileSystemHandle is readable
QueryPermission(bool writePermission)	Task<string>	Queries the current permission state of the file or directory handle. If true, queries for write permission; otherwise, queries for read permission. A string representing the permission state (e.g., "granted", "denied", "prompt").
RequestPermission(bool writePermission)	Task<string>	Requests permission to read or write to the file or directory handle. If true, requests write permission; otherwise, requests read permission. A string representing the new permission state (e.g., "granted", "denied", "prompt").
VerifyPermission(bool readWrite, bool askIfNeeded)	Task<bool>	Verifies if the user has granted the specified permission (read or read/write). Optionally requests permission if it hasn't been granted yet. If true,ifies write permission; otherwise, verifies read permission. If true, requests permission if the current state is "prompt". True if permission is granted, otherwise false.

Examples

SpawnDev.SpawnJS Mapping Note: The JavaScript examples below show the standard Web API usage. In SpawnDev.SpawnJS, the same API is available with C# conventions:

• Properties and methods use PascalCase (e.g., readyState becomes ReadyState)
• Events use ActionEvent with +=/-= (e.g., addEventListener("click", fn) becomes OnClick += handler)
• Async methods return Task<T> instead of Promise<T>
• Objects should be disposed with using statements
• Access via JS.Get<FileSystemHandle>(...) or constructor new FileSystemHandle(...)

Checking Type

// store a reference to our file handle
let fileHandle;

async function getFile() {
  // open file picker
  [fileHandle] = await window.showOpenFilePicker();

  if (fileHandle.kind === "file") {
    // run file code
  } else if (fileHandle.kind === "directory") {
    // run directory code
  }
}

Query/Request Permissions

// fileHandle is a FileSystemFileHandle
// withWrite is a boolean set to true if write

async function verifyPermission(fileHandle, withWrite) {
  const opts = {};
  if (withWrite) {
    opts.mode = "readwrite";
  }

  // Check if we already have permission, if so, return true.
  if ((await fileHandle.queryPermission(opts)) === "granted") {
    return true;
  }

  // Request permission to the file, if the user grants permission, return true.
  if ((await fileHandle.requestPermission(opts)) === "granted") {
    return true;
  }

  // The user did not grant permission, return false.
  return false;
}

Comparing Entries

function removeMatches(fileEntry, entriesArr) {
  const newArr = entriesArr.filter((entry) => !fileEntry.isSameEntry(entry));

  return newArr;
}

See full example on MDN