add http_get_cache

2026-01-20 23:18:39 -08:00
parent 572c0789b7
commit 811e884481
168 changed files with 37335 additions and 0 deletions
@@ -0,0 +1,188 @@
+import 'dart:async';
+import 'dart:ui' as ui;
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
+import 'package:http/http.dart';
+
+import 'http_get_cache.dart';
+
+/// Fetches the given URL from the network, associating it with the given scale.
+///
+/// The image will be cached regardless of cache headers from the server.
+///
+/// See also:
+///
+///  * [Image.network].
+///  * https://pub.dev/packages/dio_image_provider
+///  * https://github.com/dart-lang/http/tree/master/pkgs/flutter_http_example
+@immutable
+class HttpImageProvider extends ImageProvider<HttpImageProvider> {
+  /// Can be set to override the default [Client] for the
+  /// [HttpImageProvider].
+  static Client defaultClient = httpClient();
+
+  final Future<Uint8List?> Function(Request request)? readFromCache;
+  final Future<void> Function(Request request, Uint8List bytes)? writeToCache;
+
+  /// Creates an object that fetches the image at the given URL.
+  ///
+  /// The arguments [url] and [scale] must not be null.
+  /// [client] will be the default [Client] if not set.
+  HttpImageProvider.string(
+    String url, {
+    this.scale = 1.0,
+    this.headers,
+    Client? client,
+    this.readFromCache,
+    this.writeToCache,
+  })  : client = client ?? defaultClient,
+        url = Uri.parse(url);
+
+  /// Creates an object that fetches the image at the given URL.
+  ///
+  /// The arguments [url] and [scale] must not be null.
+  /// [client] will be the default [Client] if not set.
+  HttpImageProvider(
+    this.url, {
+    this.scale = 1.0,
+    this.headers,
+    Client? client,
+    this.readFromCache,
+    this.writeToCache,
+  }) : client = client ?? defaultClient;
+
+  /// The URL from which the image will be fetched.
+  final Uri url;
+
+  /// The scale to place in the [ImageInfo] object of the image.
+  final double scale;
+
+  /// The HTTP headers that will be used with [Client.get] to fetch image from network.
+  ///
+  /// When running flutter on the web, headers are not used.
+  final Map<String, String>? headers;
+
+  /// [client] will be the default [Client] if not set.
+  final Client client;
+
+  @override
+  Future<HttpImageProvider> obtainKey(ImageConfiguration configuration) {
+    return SynchronousFuture<HttpImageProvider>(this);
+  }
+
+  final controller = StreamController<ImageChunkEvent>();
+
+  @override
+  ImageStreamCompleter loadImage(
+    HttpImageProvider key,
+    ImageDecoderCallback decode,
+  ) {
+    return MultiFrameImageStreamCompleter(
+      codec: _loadAsync(key, decode),
+      scale: key.scale,
+      debugLabel: key.url.toString(),
+      informationCollector: () => <DiagnosticsNode>[
+        DiagnosticsProperty<ImageProvider>('Image provider', this),
+        DiagnosticsProperty<HttpImageProvider>('Image key', key),
+      ],
+      chunkEvents: controller.stream,
+    );
+  }
+
+  Future<ui.Codec> _loadAsync(
+    HttpImageProvider key,
+    ImageDecoderCallback decode,
+  ) async {
+    try {
+      assert(key == this);
+
+      // final head = await client.head(url, headers: headers);
+      // if (head.statusCode == 200) {
+      //   final contentLength = head.headers['content-length'];
+      //   if (contentLength != null) {
+      //     totalBytes = int.tryParse(contentLength);
+      //   }
+      // }
+
+      int? totalBytes;
+      int currentBytes = 0;
+      final list = <int>[];
+      final req = Request('GET', url);
+      if (headers != null) req.headers.addAll(headers!);
+
+      // Check cache
+      if (readFromCache != null) {
+        final bytes = await readFromCache!(req);
+        if (bytes != null) {
+          final buffer = await ui.ImmutableBuffer.fromUint8List(bytes);
+          return decode(buffer);
+        }
+      }
+
+      final res = await client.send(req);
+      totalBytes = res.contentLength;
+      if (res.statusCode != 200) {
+        throw NetworkImageLoadException(
+          uri: url,
+          statusCode: res.statusCode,
+        );
+      }
+
+      await res.stream.asyncMap((e) {
+        currentBytes += e.length;
+        controller.add(ImageChunkEvent(
+          expectedTotalBytes: totalBytes,
+          cumulativeBytesLoaded: currentBytes,
+        ));
+        list.addAll(e);
+        return e;
+      }).last;
+
+      final bytes = Uint8List.fromList(list);
+      if (bytes.lengthInBytes == 0) {
+        throw NetworkImageLoadException(
+          uri: url,
+          statusCode: res.statusCode,
+        );
+      }
+
+      // Write to cache
+      if (writeToCache != null) {
+        await writeToCache!(req, bytes);
+      }
+
+      final buffer = await ui.ImmutableBuffer.fromUint8List(bytes);
+      return decode(buffer);
+    } catch (e) {
+      // Depending on where the exception was thrown, the image cache may not
+      // have had a chance to track the key in the cache at all.
+      // Schedule a microtask to give the cache a chance to add the key.
+      scheduleMicrotask(() {
+        PaintingBinding.instance.imageCache.evict(key);
+      });
+      rethrow;
+    }
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType) {
+      return false;
+    }
+    return other is HttpImageProvider &&
+        other.url == url &&
+        other.scale == scale;
+  }
+
+  @override
+  int get hashCode => Object.hash(url, scale);
+
+  @override
+  String toString() =>
+      '${objectRuntimeType(this, 'HttpImageProvider')}("$url", scale: $scale)';
+}
+
+@Deprecated('Use HttpImageProvider instead')
+typedef HttpImage = HttpImageProvider;