| // Copyright (c) 2022, 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. |
| |
| /// A lightweight html parser and DOM model. |
| |
| import 'dart:convert'; |
| |
| // ignore: implementation_imports |
| import 'package:analyzer/src/manifest/manifest_validator.dart'; |
| |
| const _htmlEscape = HtmlEscape(HtmlEscapeMode.element); |
| |
| abstract class Node { |
| Element? parent; |
| |
| final List<Node> nodes = []; |
| } |
| |
| class Element extends Node { |
| String name; |
| |
| Map<String, String> attributes = {}; |
| |
| List<Element> get children => nodes.whereType<Element>().toList(); |
| |
| Element.tag(this.name); |
| |
| // This is for compatibility with the package:html DOM API. |
| String? get localName => name; |
| |
| void append(Node child) { |
| child.parent = this; |
| nodes.add(child); |
| } |
| |
| List<String> get classes { |
| final classes = attributes['class']; |
| if (classes != null) { |
| return classes.split(' ').toList(); |
| } else { |
| return const []; |
| } |
| } |
| } |
| |
| class Text extends Node { |
| static final RegExp tagRegex = RegExp(r'<[^>]+>'); |
| |
| final String text; |
| |
| Text(this.text); |
| |
| @override |
| List<Node> get nodes => const []; |
| |
| String get textRemoveTags { |
| return text.replaceAll(tagRegex, ''); |
| } |
| } |
| |
| class Document extends Element { |
| static const Set<String> selfClosing = { |
| 'br', |
| 'link', |
| 'meta', |
| }; |
| |
| Document() : super.tag(''); |
| |
| /// Return the full HTML text for the document. |
| String get outerHtml { |
| var buf = StringBuffer(); |
| |
| void emitNode(Node node) { |
| if (node is Element) { |
| buf.write('<${node.name}'); |
| for (var attr in node.attributes.keys) { |
| buf.write(' $attr="${node.attributes[attr]}"'); |
| } |
| if (node.nodes.length == 1 && |
| node.nodes.first is Text && |
| !(node.nodes.first as Text).text.contains('\n')) { |
| buf.write('>'); |
| var text = node.nodes.first as Text; |
| buf.write(_htmlEscape.convert(text.text)); |
| buf.write('</${node.name}>'); |
| } else { |
| buf.write('>'); |
| for (var child in node.nodes) { |
| emitNode(child); |
| } |
| if (!selfClosing.contains(node.name)) { |
| buf.write('</${node.name}>'); |
| } |
| } |
| } else if (node is Text) { |
| buf.write(_htmlEscape.convert(node.text)); |
| } else { |
| throw 'unknown node type: $node'; |
| } |
| } |
| |
| buf.write('<!DOCTYPE html>'); |
| |
| for (var child in nodes) { |
| emitNode(child); |
| } |
| |
| buf.writeln(); |
| |
| return buf.toString(); |
| } |
| } |
| |
| /// Given HTML text, return a parsed HTML tree. |
| Document parse(String htmlContents, Uri uri) { |
| final RegExp commentRegex = RegExp(r'<!--[^>]+-->'); |
| |
| Element createElement(XmlElement xmlElement) { |
| // element |
| var element = Element.tag(xmlElement.name); |
| |
| // attributes |
| for (var key in xmlElement.attributes.keys) { |
| element.attributes[key] = xmlElement.attributes[key]!.value; |
| } |
| |
| // From the immediate children, determine where the text between the tags is |
| // report any such non empty text as Text nodes. |
| var text = xmlElement.sourceSpan?.text ?? ''; |
| |
| if (!text.endsWith('/>')) { |
| var indices = <int>[]; |
| var offset = xmlElement.sourceSpan!.start.offset; |
| |
| indices.add(text.indexOf('>') + 1); |
| for (var child in xmlElement.children) { |
| var childSpan = child.sourceSpan!; |
| indices.add(childSpan.start.offset - offset); |
| indices.add(childSpan.end.offset - offset); |
| } |
| indices.add(text.lastIndexOf('<')); |
| |
| var textNodes = <Text>[]; |
| for (var index = 0; index < indices.length; index += 2) { |
| var start = indices[index]; |
| var end = indices[index + 1]; |
| // Remove html comments (<!-- -->) from text. |
| textNodes.add( |
| Text(text.substring(start, end).replaceAll(commentRegex, '')), |
| ); |
| } |
| |
| element.append(textNodes.removeAt(0)); |
| |
| for (var child in xmlElement.children) { |
| element.append(createElement(child)); |
| element.append(textNodes.removeAt(0)); |
| } |
| |
| element.nodes.removeWhere((node) => node is Text && node.text.isEmpty); |
| } |
| |
| return element; |
| } |
| |
| var parser = ManifestParser.general(htmlContents, uri: uri); |
| var result = parser.parseXmlTag(); |
| |
| while (result.parseResult != ParseTagResult.eof.parseResult) { |
| if (result.element != null) { |
| var document = Document(); |
| document.append(createElement(result.element!)); |
| return document; |
| } |
| |
| result = parser.parseXmlTag(); |
| } |
| |
| throw 'parse error - element not found'; |
| } |
