sdk/lib/io/io.dart

// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// File, socket, HTTP, and other I/O support for non-web applications.
///
/// **Important:** Browser-based apps can't use this library.
/// Only the following can import and use the dart:io library:
///   - Servers
///   - Command-line scripts
///   - Flutter mobile apps
///   - Flutter desktop apps
///
/// This library allows you to work with files, directories,
/// sockets, processes, HTTP servers and clients, and more.
/// Many operations related to input and output are asynchronous
/// and are handled using [Future]s or [Stream]s, both of which
/// are defined in the [dart:async
/// library](../dart-async/dart-async-library.html).
///
/// To use the dart:io library in your code:
/// ```dart
/// import 'dart:io';
/// ```
/// For an introduction to I/O in Dart, see the [dart:io library
/// tour](https://dart.dev/guides/libraries/library-tour#dartio).
///
/// ## File, Directory, and Link
///
/// An instance of [File], [Directory], or [Link] represents a file,
/// directory, or link, respectively, in the native file system.
///
/// You can manipulate the file system through objects of these types.
/// For example, you can rename a file or directory:
/// ```dart
/// File myFile = File('myFile.txt');
/// myFile.rename('yourFile.txt').then((_) => print('file renamed'));
/// ```
/// Many methods provided by the [File], [Directory], and [Link] classes
/// run asynchronously and return a [Future].
///
/// ## FileSystemEntity
///
/// [File], [Directory], and [Link] all extend [FileSystemEntity].
/// In addition to being the superclass for these classes,
/// FileSystemEntity has a number of static methods for working with paths.
///
/// To get information about a path,
/// you can use the [FileSystemEntity] static methods
/// such as [FileSystemEntity.isDirectory], [FileSystemEntity.isFile],
/// and [FileSystemEntity.exists].
/// Because file system access involves I/O, these methods
/// are asynchronous and return a [Future].
/// ```dart
/// FileSystemEntity.isDirectory(myPath).then((isDir) {
///   if (isDir) {
///     print('$myPath is a directory');
///   } else {
///     print('$myPath is not a directory');
///   }
/// });
/// ```
/// ## HttpServer and HttpClient
///
/// The classes [HttpClient] and [HttpServer] provide low-level HTTP
/// functionality.
///
/// Instead of using these classes directly, consider using more
/// developer-friendly and composable APIs found in packages.
///
/// For HTTP clients, look at [`package:http`](https://pub.dev/packages/http).
///
/// For HTTP servers, look at
/// [Write HTTP servers](https://dart.dev/tutorials/server/httpserver) on
/// [dart.dev](https://dart.dev/).
///
/// ## Process
///
/// The [Process] class provides a way to run a process on
/// the native machine.
/// For example, the following code spawns a process that recursively lists
/// the files under `web`.
/// ```dart
/// Process.start('ls', ['-R', 'web']).then((process) {
///   stdout.addStream(process.stdout);
///   stderr.addStream(process.stderr);
///   process.exitCode.then(print);
/// });
/// ```
/// Using [Process.start] returns a [Future],
/// which completes with a [Process] object when the process has started.
/// This [Process] object allows you to interact
/// with the process while it is running.
/// Using [Process.run] returns a [Future],
/// which completes with a [ProcessResult] object when the spawned process has
/// terminated. This [ProcessResult] object collects the output and exit code
/// from the process.
///
/// When using [Process.start],
/// you need to read all data coming on the [Process.stdout] and [Process.stderr]
/// streams, otherwise the system resources will not be freed.
///
/// ## WebSocket
///
/// The [WebSocket] class provides support for the web socket protocol. This
/// allows full-duplex communications between client and server applications.
///
/// A web socket server uses a normal HTTP server for accepting web socket
/// connections. The initial handshake is a HTTP request which is then upgraded to a
/// web socket connection.
/// The server upgrades the request using [WebSocketTransformer]
/// and listens for the data on the returned web socket.
/// For example, here's a mini server that listens for 'ws' data
/// on a WebSocket:
/// ```dart import:async
/// runZoned(() async {
///   var server = await HttpServer.bind('127.0.0.1', 4040);
///   server.listen((HttpRequest req) async {
///     if (req.uri.path == '/ws') {
///       var socket = await WebSocketTransformer.upgrade(req);
///       socket.listen(handleMsg);
///     }
///   });
/// }, onError: (e) => print("An error occurred."));
/// ```
/// The client connects to the [WebSocket] using the [WebSocket.connect] method
/// and a URI that uses the Web Socket protocol.
/// The client can write to the [WebSocket] with the [WebSocket.add] method.
/// For example,
/// ```dart
/// var socket = await WebSocket.connect('ws://127.0.0.1:4040/ws');
/// socket.add('Hello, World!');
/// ```
/// Check out the
/// [websocket_sample](https://github.com/dart-lang/dart-samples/tree/master/html5/web/websockets/basics)
/// app, which uses [WebSocket]s to communicate with a server.
///
/// ## Socket and ServerSocket
///
/// Clients and servers use [Socket]s to communicate using the TCP protocol.
/// Use [ServerSocket] on the server side and [Socket] on the client.
/// The server creates a listening socket using the `bind()` method and
/// then listens for incoming connections on the socket. For example:
/// ```dart import:convert
/// ServerSocket.bind('127.0.0.1', 4041)
///   .then((serverSocket) {
///     serverSocket.listen((socket) {
///       socket.transform(utf8.decoder).listen(print);
///     });
///   });
/// ```
/// A client connects a [Socket] using the `connect()` method,
/// which returns a [Future].
/// Using `write()`, `writeln()`, or `writeAll()` are the easiest ways to
/// send data over the socket.
/// For example:
/// ```dart
/// Socket.connect('127.0.0.1', 4041).then((socket) {
///   socket.write('Hello, World!');
/// });
/// ```
/// Besides [Socket] and [ServerSocket], the [RawSocket] and
/// [RawServerSocket] classes are available for lower-level access
/// to async socket IO.
///
/// ## Standard output, error, and input streams
///
/// This library provides the standard output, error, and input
/// streams, named [stdout], [stderr], and [stdin], respectively.
///
/// The [stdout] and [stderr] streams are both [IOSink]s and have the same set
/// of methods and properties.
///
/// To write a string to [stdout]:
/// ```dart
/// stdout.writeln('Hello, World!');
/// ```
/// To write a list of objects to [stderr]:
/// ```dart
/// stderr.writeAll([ 'That ', 'is ', 'an ', 'error.', '\n']);
/// ```
/// The standard input stream is a true [Stream], so it inherits
/// properties and methods from the [Stream] class.
///
/// To read text synchronously from the command line
/// (the program blocks waiting for user to type information):
/// ```dart
/// String? inputText = stdin.readLineSync();
/// ```
/// {@category VM}
library dart.io;

import 'dart:async';
import 'dart:async' as dart_async show runZoned;
import 'dart:_internal' hide Symbol;
import 'dart:collection'
    show HashMap, HashSet, Queue, ListQueue, MapBase, UnmodifiableMapView;
import 'dart:convert';
import 'dart:developer' hide log;
import 'dart:_http' show HttpClient, HttpProfiler, ServerSocketBase;
import 'dart:isolate';
import 'dart:math';
import 'dart:typed_data';

export 'dart:_http'
    show
        HttpDate,
        BadCertificateCallback,
        HttpOverrides,
        WebSocketStatus,
        CompressionOptions,
        WebSocketTransformer,
        WebSocket,
        WebSocketException,
        HttpServer,
        HttpConnectionsInfo,
        HttpHeaders,
        HeaderValue,
        HttpSession,
        ContentType,
        SameSite,
        Cookie,
        HttpRequest,
        HttpResponse,
        HttpClient,
        HttpClientRequest,
        HttpClientResponse,
        HttpClientResponseCompressionState,
        HttpClientCredentials,
        HttpClientBasicCredentials,
        HttpClientBearerCredentials,
        HttpClientDigestCredentials,
        HttpConnectionInfo,
        RedirectInfo,
        HttpException,
        RedirectException;
@Deprecated("Import BytesBuilder from dart:typed_data instead")
export 'dart:_internal' show BytesBuilder;
export 'dart:_internal' show HttpStatus;

part 'common.dart';
part 'data_transformer.dart';
part 'directory.dart';
part 'directory_impl.dart';
part 'embedder_config.dart';
part 'eventhandler.dart';
part 'file.dart';
part 'file_impl.dart';
part 'file_system_entity.dart';
part 'io_resource_info.dart';
part 'io_sink.dart';
part 'io_service.dart';
part 'link.dart';
part 'namespace_impl.dart';
part 'network_profiling.dart';
part 'overrides.dart';
part 'platform.dart';
part 'platform_impl.dart';
part 'process.dart';
part 'secure_server_socket.dart';
part 'secure_socket.dart';
part 'security_context.dart';
part 'service_object.dart';
part 'socket.dart';
part 'stdio.dart';
part 'string_transformer.dart';
part 'sync_socket.dart';