ba626dc83a
This implements dual compile via the newly available flutter.js bootstrapping APIs for intelligent build fallback. * Users can now use the `FlutterLoader.load` API from flutter.js * Flutter tool injects build info into the `index.html` of the user so that the bootstrapper knows which build variants are available to bootstrap * The semantics of the `--wasm` flag for `flutter build web` have changed: - Instead of producing a separate `build/web_wasm` directory, the output goes to the `build/web` directory like a normal web build - Produces a dual build that contains two build variants: dart2wasm+skwasm and dart2js+CanvasKit. The dart2wasm+skwasm will only work on Chrome in a cross-origin isolated context, all other environments will fall back to dart2js+CanvasKit. - `--wasm` and `--web-renderer` are now mutually exclusive. Since there are multiple build variants with `--wasm`, the web renderer cannot be expressed via a single command-line flag. For now, we are hard coding what build variants are produced with the `--wasm` flag, but I plan on making this more customizable in the future. * Build targets now can optionally provide a "build key" which can uniquely identify any specific parameterization of that build target. This way, the build target can invalidate itself by changing its build key. This works a bit better than just stuffing everything into the environment defines because (a) it doesn't invalidate the entire build, just the targets which are affected and (b) settings for multiple build variants don't translate well to the flat map of environment defines.
121 lines
3.5 KiB
Dart
121 lines
3.5 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'package:html/dom.dart';
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import 'package:html/parser.dart';
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import 'base/common.dart';
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/// Placeholder for base href
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const String kBaseHrefPlaceholder = r'$FLUTTER_BASE_HREF';
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/// Utility class for parsing and performing operations on the contents of the
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/// index.html file.
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///
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/// For example, to parse the base href from the index.html file:
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///
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/// ```dart
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/// String parseBaseHref(File indexHtmlFile) {
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/// final IndexHtml indexHtml = IndexHtml(indexHtmlFile.readAsStringSync());
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/// return indexHtml.getBaseHref();
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/// }
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/// ```
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class IndexHtml {
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IndexHtml(this._content);
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String get content => _content;
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String _content;
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Document _getDocument() => parse(_content);
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/// Parses the base href from the index.html file.
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String getBaseHref() {
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final Element? baseElement = _getDocument().querySelector('base');
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final String? baseHref = baseElement?.attributes == null
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? null
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: baseElement!.attributes['href'];
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if (baseHref == null || baseHref == kBaseHrefPlaceholder) {
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return '';
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}
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if (!baseHref.startsWith('/')) {
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throw ToolExit(
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'Error: The base href in "web/index.html" must be absolute (i.e. start '
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'with a "/"), but found: `${baseElement!.outerHtml}`.\n'
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'$_kBasePathExample',
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);
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}
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if (!baseHref.endsWith('/')) {
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throw ToolExit(
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'Error: The base href in "web/index.html" must end with a "/", but found: `${baseElement!.outerHtml}`.\n'
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'$_kBasePathExample',
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);
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}
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return stripLeadingSlash(stripTrailingSlash(baseHref));
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}
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/// Applies substitutions to the content of the index.html file.
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void applySubstitutions({
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required String baseHref,
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required String? serviceWorkerVersion,
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String? buildConfig,
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}) {
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if (_content.contains(kBaseHrefPlaceholder)) {
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_content = _content.replaceAll(kBaseHrefPlaceholder, baseHref);
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}
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if (serviceWorkerVersion != null) {
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_content = _content
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.replaceFirst(
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// Support older `var` syntax as well as new `const` syntax
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RegExp('(const|var) serviceWorkerVersion = null'),
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'const serviceWorkerVersion = "$serviceWorkerVersion"',
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)
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// This is for legacy index.html that still uses the old service
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// worker loading mechanism.
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.replaceFirst(
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"navigator.serviceWorker.register('flutter_service_worker.js')",
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"navigator.serviceWorker.register('flutter_service_worker.js?v=$serviceWorkerVersion')",
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);
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}
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if (buildConfig != null) {
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_content = _content.replaceFirst(
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'{{flutter_build_config}}',
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buildConfig,
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);
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}
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}
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}
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/// Strips the leading slash from a path.
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String stripLeadingSlash(String path) {
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while (path.startsWith('/')) {
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path = path.substring(1);
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}
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return path;
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}
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/// Strips the trailing slash from a path.
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String stripTrailingSlash(String path) {
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while (path.endsWith('/')) {
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path = path.substring(0, path.length - 1);
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}
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return path;
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}
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const String _kBasePathExample = '''
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For example, to serve from the root use:
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<base href="/">
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To serve from a subpath "foo" (i.e. http://localhost:8080/foo/ instead of http://localhost:8080/) use:
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<base href="/foo/">
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For more information, see: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
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''';
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