feat:api Add support for extracting EPUB files in ExtractProcessor (#3254)

Co-authored-by: crazywoola <427733928@qq.com>

api/core/rag/extractor/unstructured/unstructured_epub_extractor.py

@@ -0,0 +1,37 @@
+import logging
+
+from core.rag.extractor.extractor_base import BaseExtractor
+from core.rag.models.document import Document
+
+logger = logging.getLogger(__name__)
+
+
+class UnstructuredEpubExtractor(BaseExtractor):
+    """Load epub files.
+
+
+    Args:
+        file_path: Path to the file to load.
+    """
+
+    def __init__(
+        self,
+        file_path: str,
+        api_url: str = None,
+    ):
+        """Initialize with file path."""
+        self._file_path = file_path
+        self._api_url = api_url
+
+    def extract(self) -> list[Document]:
+        from unstructured.partition.epub import partition_epub
+
+        elements = partition_epub(filename=self._file_path, xml_keep_tags=True)
+        from unstructured.chunking.title import chunk_by_title
+        chunks = chunk_by_title(elements, max_characters=2000, combine_text_under_n_chars=2000)
+        documents = []
+        for chunk in chunks:
+            text = chunk.text.strip()
+            documents.append(Document(page_content=text))
+
+        return documents