W3C HTML规范中“处理器”的深度解析

# 假设有一个简化的HTML处理器类
class SimpleHtmlProcessor:
    def __init__(self):
        self.supported_encodings = ["UTF-8", "UTF-16", "Windows-1252", "ISO-8859"]
        self.dom_tree = None

    def process_html_document(self, raw_html_bytes, declared_encoding=None):
        """
        处理HTML文档的字节流。
        :param raw_html_bytes: 原始HTML文档的字节数据。
        :param declared_encoding: 文档中声明的编码（如<meta charset="...">）。
        """
        if not raw_html_bytes:
            raise ValueError("HTML document cannot be empty.")

        # 1. 识别并解码字符编码
        actual_encoding = self._detect_encoding(raw_html_bytes, declared_encoding)
        if actual_encoding not in self.supported_encodings:
            raise UnsupportedEncodingError(f"Encoding '{actual_encoding}' is not supported.")

        html_string = raw_html_bytes.decode(actual_encoding)
        print(f"Decoded HTML using {actual_encoding}:\n{html_string[:100]}...")

        # 2. 模拟解析过程（构建DOM树）
        self.dom_tree = self._parse_html_string(html_string)
        print("HTML document successfully parsed into a DOM-like structure.")

        # 3. 其他处理，如渲染、数据提取等
        self._perform_additional_tasks()

    def _detect_encoding(self, raw_bytes, declared_encoding):
        # 实际的编码检测涉及字节序标记 (BOM)、HTTP头、<meta charset>等
        # 这里简化为优先使用声明的编码，否则默认为UTF-8
        if declared_encoding:
            return declared_encoding
        # 简单的BOM检测
        if raw_bytes.startswith(b'\xef\xbb\xbf'): # UTF-8 BOM
            return "UTF-8"
        # 更多复杂的检测逻辑...
        return "UTF-8" # 默认 fallback

    def _parse_html_string(self, html_string):
        # 这是一个高度简化的占位符，实际解析器会构建复杂的树结构
        print("Starting HTML string parsing...")
        # 假设这里调用一个实际的HTML解析库，如BeautifulSoup或lxml
        # 例如：return BeautifulSoup(html_string, 'html.parser')
        return {"root": "html", "children": [{"tag": "head"}, {"tag": "body"}]}

    def _perform_additional_tasks(self):
        print("Performing additional tasks like rendering or data extraction...")
        # 浏览器会在这里进行布局、绘制等
        # 数据提取工具会遍历DOM树获取信息

# 示例用法
# processor = SimpleHtmlProcessor()
# with open("example.html", "rb") as f:
#     html_data = f.read()
# processor.process_html_document(html_data, declared_encoding="UTF-8")