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backend/app/processors/parsers/pdf_parser.py

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+"""PDF 解析器（PyMuPDF fallback）。"""
+
+from app.core.logging import get_logger
+
+logger = get_logger(__name__)
+
+
+def parse_pdf_with_pymupdf(file_content: bytes) -> str | None:
+    """用 PyMuPDF 解析 PDF，返回 Markdown 或 None（失败时）。"""
+    try:
+        import pymupdf  # PyMuPDF >= 1.24
+
+        doc = pymupdf.open(stream=file_content, filetype="pdf")
+        pages = []
+        for page_num in range(len(doc)):
+            page = doc.load_page(page_num)
+            text = page.get_text()
+            if text.strip():
+                pages.append(text)
+        doc.close()
+
+        if not pages:
+            return None
+
+        # 组合成 Markdown（每页一个段落）
+        markdown = "\n\n".join(pages)
+        return markdown
+    except Exception as e:
+        logger.warning("PyMuPDF 解析失败: %s", e)
+        return None
+
+
+def has_text_layer(file_content: bytes) -> bool:
+    """检查 PDF 是否有文本层。"""
+    try:
+        import pymupdf
+
+        doc = pymupdf.open(stream=file_content, filetype="pdf")
+        for page_num in range(min(3, len(doc))):  # 检查前 3 页
+            page = doc.load_page(page_num)
+            if page.get_text().strip():
+                doc.close()
+                return True
+        doc.close()
+        return False
+    except Exception:
+        return False