packages/flutter/lib/src/painting/_network_image_web.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:async';
 import 'dart:typed_data';
 import 'dart:ui' as ui;

 import 'package:flutter/foundation.dart';
 import 'package:js/js.dart';
 import 'package:js/js_util.dart' as js_util;

 import 'image_provider.dart' as image_provider;
 import 'image_stream.dart';

 /// [DomXMLHttpRequest] interop class.
 @JS()
 @staticInterop
 class DomXMLHttpRequest {}

 /// [DomXMLHttpRequest] extension.
 extension DomXMLHttpRequestExtension on DomXMLHttpRequest {
   /// Gets the response.
   external dynamic get response;

   /// Gets the response text.
   external String? get responseText;

   /// Gets the response type.
   external String get responseType;

   /// Gets the status.
   external int? get status;

   /// Set the response type.
   external set responseType(String value);

   /// Set the request header.
   external void setRequestHeader(String header, String value);

   /// Open the request.
   void open(String method, String url, bool isAsync) => js_util.callMethod(
       this, 'open', <Object>[method, url, isAsync]);

   /// Send the request.
   void send() => js_util.callMethod(this, 'send', <Object>[]);

   /// Add event listener.
   void addEventListener(String type, DomEventListener? listener,
       [bool? useCapture]) {
     if (listener != null) {
       js_util.callMethod(this, 'addEventListener',
           <Object>[type, listener, if (useCapture != null) useCapture]);
     }
   }
 }

 /// Factory function for creating [DomXMLHttpRequest].
 DomXMLHttpRequest createDomXMLHttpRequest() =>
     domCallConstructorString('XMLHttpRequest', <Object?>[])!
         as DomXMLHttpRequest;

 /// Type for event listener.
 typedef DomEventListener = void Function(DomEvent event);

 /// [DomEvent] interop object.
 @JS()
 @staticInterop
 class DomEvent {}

 /// [DomEvent] reqiured extension.
 extension DomEventExtension on DomEvent {
   /// Get the event type.
   external String get type;

   /// Initialize an event.
   void initEvent(String type, [bool? bubbles, bool? cancelable]) =>
       js_util.callMethod(this, 'initEvent', <Object>[
         type,
         if (bubbles != null) bubbles,
         if (cancelable != null) cancelable
       ]);
 }

 /// [DomProgressEvent] interop object.
 @JS()
 @staticInterop
 class DomProgressEvent extends DomEvent {}

 /// [DomProgressEvent] reqiured extension.
 extension DomProgressEventExtension on DomProgressEvent {
   /// Amount of work done.
   external int? get loaded;

   /// Total amount of work.
   external int? get total;
 }

 /// Gets a constructor from a [String].
 Object? domGetConstructor(String constructorName) =>
     js_util.getProperty(domWindow, constructorName);

 /// Calls a constructor as a [String].
 Object? domCallConstructorString(String constructorName, List<Object?> args) {
   final Object? constructor = domGetConstructor(constructorName);
   if (constructor == null) {
     return null;
   }
   return js_util.callConstructor(constructor, args);
 }

 /// The underyling window object.
 @JS('window')
 external Object get domWindow;

 /// Creates a type for an overridable factory function for testing purposes.
 typedef HttpRequestFactory = DomXMLHttpRequest Function();

 /// Default HTTP client.
 DomXMLHttpRequest _httpClient() {
   return DomXMLHttpRequest();
 }

 /// Creates an overridable factory function.
 HttpRequestFactory httpRequestFactory = _httpClient;

 /// Restores to the default HTTP request factory.
 void debugRestoreHttpRequestFactory() {
   httpRequestFactory = _httpClient;
 }

 /// The web implementation of [image_provider.NetworkImage].
 ///
 /// NetworkImage on the web does not support decoding to a specified size.
 @immutable
 class NetworkImage
     extends image_provider.ImageProvider<image_provider.NetworkImage>
     implements image_provider.NetworkImage {
   /// Creates an object that fetches the image at the given URL.
   ///
   /// The arguments [url] and [scale] must not be null.
   const NetworkImage(this.url, {this.scale = 1.0, this.headers})
       : assert(url != null),
         assert(scale != null);

   @override
   final String url;

   @override
   final double scale;

   @override
   final Map<String, String>? headers;

   @override
   Future<NetworkImage> obtainKey(image_provider.ImageConfiguration configuration) {
     return SynchronousFuture<NetworkImage>(this);
   }

   @override
   ImageStreamCompleter load(image_provider.NetworkImage key, image_provider.DecoderCallback decode) {
     // Ownership of this controller is handed off to [_loadAsync]; it is that
     // method's responsibility to close the controller's stream when the image
     // has been loaded or an error is thrown.
     final StreamController<ImageChunkEvent> chunkEvents =
         StreamController<ImageChunkEvent>();

     return MultiFrameImageStreamCompleter(
       chunkEvents: chunkEvents.stream,
       codec: _loadAsync(key as NetworkImage, null, decode, chunkEvents),
       scale: key.scale,
       debugLabel: key.url,
       informationCollector: _imageStreamInformationCollector(key),
     );
   }

   @override
   ImageStreamCompleter loadBuffer(image_provider.NetworkImage key, image_provider.DecoderBufferCallback decode) {
     // Ownership of this controller is handed off to [_loadAsync]; it is that
     // method's responsibility to close the controller's stream when the image
     // has been loaded or an error is thrown.
     final StreamController<ImageChunkEvent> chunkEvents =
         StreamController<ImageChunkEvent>();

     return MultiFrameImageStreamCompleter(
       chunkEvents: chunkEvents.stream,
       codec: _loadAsync(key as NetworkImage, decode, null, chunkEvents),
       scale: key.scale,
       debugLabel: key.url,
       informationCollector: _imageStreamInformationCollector(key),
     );
   }

   InformationCollector? _imageStreamInformationCollector(image_provider.NetworkImage key) {
     InformationCollector? collector;
     assert(() {
       collector = () => <DiagnosticsNode>[
         DiagnosticsProperty<image_provider.ImageProvider>('Image provider', this),
         DiagnosticsProperty<NetworkImage>('Image key', key as NetworkImage),
       ];
       return true;
     }());
     return collector;
   }

   // TODO(garyq): We should eventually support custom decoding of network images on Web as
   // well, see https://github.com/flutter/flutter/issues/42789.
   //
   // Web does not support decoding network images to a specified size. The decode parameter
   // here is ignored and the web-only `ui.webOnlyInstantiateImageCodecFromUrl` will be used
   // directly in place of the typical `instantiateImageCodec` method.
   Future<ui.Codec> _loadAsync(
     NetworkImage key,
     image_provider.DecoderBufferCallback? decode,
     image_provider.DecoderCallback? decodeDepreacted,
     StreamController<ImageChunkEvent> chunkEvents,
   ) async {
     assert(key == this);

     final Uri resolved = Uri.base.resolve(key.url);

     // We use a different method when headers are set because the
     // `ui.webOnlyInstantiateImageCodecFromUrl` method is not capable of handling headers.
     if (key.headers?.isNotEmpty ?? false) {
       final Completer<DomXMLHttpRequest> completer =
           Completer<DomXMLHttpRequest>();
       final DomXMLHttpRequest request = httpRequestFactory();

       request.open('GET', key.url, true);
       request.responseType = 'arraybuffer';
       key.headers!.forEach((String header, String value) {
         request.setRequestHeader(header, value);
       });

       request.addEventListener('load', allowInterop((DomEvent e) {
         final int? status = request.status;
         final bool accepted = status! >= 200 && status < 300;
         final bool fileUri = status == 0; // file:// URIs have status of 0.
         final bool notModified = status == 304;
         final bool unknownRedirect = status > 307 && status < 400;
         final bool success =
             accepted || fileUri || notModified || unknownRedirect;

         if (success) {
           completer.complete(request);
         } else {
           completer.completeError(e);
           throw image_provider.NetworkImageLoadException(
               statusCode: request.status ?? 400, uri: resolved);
         }
       }));

       request.addEventListener('error', allowInterop(completer.completeError));

       request.send();

       await completer.future;

       final Uint8List bytes = (request.response as ByteBuffer).asUint8List();

       if (bytes.lengthInBytes == 0) {
         throw image_provider.NetworkImageLoadException(
             statusCode: request.status!, uri: resolved);
       }

       if (decode != null) {
         final ui.ImmutableBuffer buffer = await ui.ImmutableBuffer.fromUint8List(bytes);
         return decode(buffer);
       } else {
         assert(decodeDepreacted != null);
         return decodeDepreacted!(bytes);
       }
     } else {
       // This API only exists in the web engine implementation and is not
       // contained in the analyzer summary for Flutter.
       // ignore: undefined_function, avoid_dynamic_calls
       return ui.webOnlyInstantiateImageCodecFromUrl(
         resolved,
         chunkCallback: (int bytes, int total) {
           chunkEvents.add(ImageChunkEvent(
               cumulativeBytesLoaded: bytes, expectedTotalBytes: total));
         },
       ) as Future<ui.Codec>;
     }
   }

   @override
   bool operator ==(Object other) {
     if (other.runtimeType != runtimeType) {
       return false;
     }
     return other is NetworkImage && other.url == url && other.scale == scale;
   }

   @override
   int get hashCode => Object.hash(url, scale);

   @override
   String toString() =>
       '${objectRuntimeType(this, 'NetworkImage')}("$url", scale: $scale)';
 }
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:async';
	import 'dart:typed_data';
	import 'dart:ui' as ui;

	import 'package:flutter/foundation.dart';
	import 'package:js/js.dart';
	import 'package:js/js_util.dart' as js_util;

	import 'image_provider.dart' as image_provider;
	import 'image_stream.dart';

	/// [DomXMLHttpRequest] interop class.
	@JS()
	@staticInterop
	class DomXMLHttpRequest {}

	/// [DomXMLHttpRequest] extension.
	extension DomXMLHttpRequestExtension on DomXMLHttpRequest {
	/// Gets the response.
	external dynamic get response;

	/// Gets the response text.
	external String? get responseText;

	/// Gets the response type.
	external String get responseType;

	/// Gets the status.
	external int? get status;

	/// Set the response type.
	external set responseType(String value);

	/// Set the request header.
	external void setRequestHeader(String header, String value);

	/// Open the request.
	void open(String method, String url, bool isAsync) => js_util.callMethod(
	this, 'open', <Object>[method, url, isAsync]);

	/// Send the request.
	void send() => js_util.callMethod(this, 'send', <Object>[]);

	/// Add event listener.
	void addEventListener(String type, DomEventListener? listener,
	[bool? useCapture]) {
	if (listener != null) {
	js_util.callMethod(this, 'addEventListener',
	<Object>[type, listener, if (useCapture != null) useCapture]);
	}
	}
	}

	/// Factory function for creating [DomXMLHttpRequest].
	DomXMLHttpRequest createDomXMLHttpRequest() =>
	domCallConstructorString('XMLHttpRequest', <Object?>[])!
	as DomXMLHttpRequest;

	/// Type for event listener.
	typedef DomEventListener = void Function(DomEvent event);

	/// [DomEvent] interop object.
	@JS()
	@staticInterop
	class DomEvent {}

	/// [DomEvent] reqiured extension.
	extension DomEventExtension on DomEvent {
	/// Get the event type.
	external String get type;

	/// Initialize an event.
	void initEvent(String type, [bool? bubbles, bool? cancelable]) =>
	js_util.callMethod(this, 'initEvent', <Object>[
	type,
	if (bubbles != null) bubbles,
	if (cancelable != null) cancelable
	]);
	}

	/// [DomProgressEvent] interop object.
	@JS()
	@staticInterop
	class DomProgressEvent extends DomEvent {}

	/// [DomProgressEvent] reqiured extension.
	extension DomProgressEventExtension on DomProgressEvent {
	/// Amount of work done.
	external int? get loaded;

	/// Total amount of work.
	external int? get total;
	}

	/// Gets a constructor from a [String].
	Object? domGetConstructor(String constructorName) =>
	js_util.getProperty(domWindow, constructorName);

	/// Calls a constructor as a [String].
	Object? domCallConstructorString(String constructorName, List<Object?> args) {
	final Object? constructor = domGetConstructor(constructorName);
	if (constructor == null) {
	return null;
	}
	return js_util.callConstructor(constructor, args);
	}

	/// The underyling window object.
	@JS('window')
	external Object get domWindow;

	/// Creates a type for an overridable factory function for testing purposes.
	typedef HttpRequestFactory = DomXMLHttpRequest Function();

	/// Default HTTP client.
	DomXMLHttpRequest _httpClient() {
	return DomXMLHttpRequest();
	}

	/// Creates an overridable factory function.
	HttpRequestFactory httpRequestFactory = _httpClient;

	/// Restores to the default HTTP request factory.
	void debugRestoreHttpRequestFactory() {
	httpRequestFactory = _httpClient;
	}

	/// The web implementation of [image_provider.NetworkImage].
	///
	/// NetworkImage on the web does not support decoding to a specified size.
	@immutable
	class NetworkImage
	extends image_provider.ImageProvider<image_provider.NetworkImage>
	implements image_provider.NetworkImage {
	/// Creates an object that fetches the image at the given URL.
	///
	/// The arguments [url] and [scale] must not be null.
	const NetworkImage(this.url, {this.scale = 1.0, this.headers})
	: assert(url != null),
	assert(scale != null);

	@override
	final String url;

	@override
	final double scale;

	@override
	final Map<String, String>? headers;

	@override
	Future<NetworkImage> obtainKey(image_provider.ImageConfiguration configuration) {
	return SynchronousFuture<NetworkImage>(this);
	}

	@override
	ImageStreamCompleter load(image_provider.NetworkImage key, image_provider.DecoderCallback decode) {
	// Ownership of this controller is handed off to [_loadAsync]; it is that
	// method's responsibility to close the controller's stream when the image
	// has been loaded or an error is thrown.
	final StreamController<ImageChunkEvent> chunkEvents =
	StreamController<ImageChunkEvent>();

	return MultiFrameImageStreamCompleter(
	chunkEvents: chunkEvents.stream,
	codec: _loadAsync(key as NetworkImage, null, decode, chunkEvents),
	scale: key.scale,
	debugLabel: key.url,
	informationCollector: _imageStreamInformationCollector(key),
	);
	}

	@override
	ImageStreamCompleter loadBuffer(image_provider.NetworkImage key, image_provider.DecoderBufferCallback decode) {
	// Ownership of this controller is handed off to [_loadAsync]; it is that
	// method's responsibility to close the controller's stream when the image
	// has been loaded or an error is thrown.
	final StreamController<ImageChunkEvent> chunkEvents =
	StreamController<ImageChunkEvent>();

	return MultiFrameImageStreamCompleter(
	chunkEvents: chunkEvents.stream,
	codec: _loadAsync(key as NetworkImage, decode, null, chunkEvents),
	scale: key.scale,
	debugLabel: key.url,
	informationCollector: _imageStreamInformationCollector(key),
	);
	}

	InformationCollector? _imageStreamInformationCollector(image_provider.NetworkImage key) {
	InformationCollector? collector;
	assert(() {
	collector = () => <DiagnosticsNode>[
	DiagnosticsProperty<image_provider.ImageProvider>('Image provider', this),
	DiagnosticsProperty<NetworkImage>('Image key', key as NetworkImage),
	];
	return true;
	}());
	return collector;
	}

	// TODO(garyq): We should eventually support custom decoding of network images on Web as
	// well, see https://github.com/flutter/flutter/issues/42789.
	//
	// Web does not support decoding network images to a specified size. The decode parameter
	// here is ignored and the web-only `ui.webOnlyInstantiateImageCodecFromUrl` will be used
	// directly in place of the typical `instantiateImageCodec` method.
	Future<ui.Codec> _loadAsync(
	NetworkImage key,
	image_provider.DecoderBufferCallback? decode,
	image_provider.DecoderCallback? decodeDepreacted,
	StreamController<ImageChunkEvent> chunkEvents,
	) async {
	assert(key == this);

	final Uri resolved = Uri.base.resolve(key.url);

	// We use a different method when headers are set because the
	// `ui.webOnlyInstantiateImageCodecFromUrl` method is not capable of handling headers.
	if (key.headers?.isNotEmpty ?? false) {
	final Completer<DomXMLHttpRequest> completer =
	Completer<DomXMLHttpRequest>();
	final DomXMLHttpRequest request = httpRequestFactory();

	request.open('GET', key.url, true);
	request.responseType = 'arraybuffer';
	key.headers!.forEach((String header, String value) {
	request.setRequestHeader(header, value);
	});

	request.addEventListener('load', allowInterop((DomEvent e) {
	final int? status = request.status;
	final bool accepted = status! >= 200 && status < 300;
	final bool fileUri = status == 0; // file:// URIs have status of 0.
	final bool notModified = status == 304;
	final bool unknownRedirect = status > 307 && status < 400;
	final bool success =
	accepted \|\| fileUri \|\| notModified \|\| unknownRedirect;

	if (success) {
	completer.complete(request);
	} else {
	completer.completeError(e);
	throw image_provider.NetworkImageLoadException(
	statusCode: request.status ?? 400, uri: resolved);
	}
	}));

	request.addEventListener('error', allowInterop(completer.completeError));

	request.send();

	await completer.future;

	final Uint8List bytes = (request.response as ByteBuffer).asUint8List();

	if (bytes.lengthInBytes == 0) {
	throw image_provider.NetworkImageLoadException(
	statusCode: request.status!, uri: resolved);
	}

	if (decode != null) {
	final ui.ImmutableBuffer buffer = await ui.ImmutableBuffer.fromUint8List(bytes);
	return decode(buffer);
	} else {
	assert(decodeDepreacted != null);
	return decodeDepreacted!(bytes);
	}
	} else {
	// This API only exists in the web engine implementation and is not
	// contained in the analyzer summary for Flutter.
	// ignore: undefined_function, avoid_dynamic_calls
	return ui.webOnlyInstantiateImageCodecFromUrl(
	resolved,
	chunkCallback: (int bytes, int total) {
	chunkEvents.add(ImageChunkEvent(
	cumulativeBytesLoaded: bytes, expectedTotalBytes: total));
	},
	) as Future<ui.Codec>;
	}
	}

	@override
	bool operator ==(Object other) {
	if (other.runtimeType != runtimeType) {
	return false;
	}
	return other is NetworkImage && other.url == url && other.scale == scale;
	}

	@override
	int get hashCode => Object.hash(url, scale);

	@override
	String toString() =>
	'${objectRuntimeType(this, 'NetworkImage')}("$url", scale: $scale)';
	}