refactor: RAG Refactor (#985)

Co-authored-by: Aralhi <xiaoping0501@gmail.com>
Co-authored-by: csunny <cfqsunny@163.com>

dbgpt/rag/knowledge/url.py

@@ -0,0 +1,55 @@
+from typing import Optional, Any, List
+
+from dbgpt.rag.chunk import Document
+from dbgpt.rag.knowledge.base import KnowledgeType, Knowledge, ChunkStrategy
+
+
+class URLKnowledge(Knowledge):
+    def __init__(
+        self,
+        url: Optional[str] = None,
+        knowledge_type: KnowledgeType = KnowledgeType.URL,
+        source_column: Optional[str] = None,
+        encoding: Optional[str] = "utf-8",
+        loader: Optional[Any] = None,
+        **kwargs: Any,
+    ) -> None:
+        """Initialize with Knowledge arguments.
+        Args:
+            url:(Optional[str]) url
+            knowledge_type:(KnowledgeType) knowledge type
+            source_column:(Optional[str]) source column
+            encoding:(Optional[str]) csv encoding
+            loader:(Optional[Any]) loader
+        """
+        self._path = url
+        self._type = knowledge_type
+        self._loader = loader
+        self._encoding = encoding
+        self._source_column = source_column
+
+    def _load(self) -> List[Document]:
+        """Fetch URL document from loader"""
+        if self._loader:
+            documents = self._loader.load()
+        else:
+            from langchain.document_loaders import WebBaseLoader
+
+            web_reader = WebBaseLoader(web_path=self._path)
+            documents = web_reader.load()
+        return [Document.langchain2doc(lc_document) for lc_document in documents]
+
+    @classmethod
+    def support_chunk_strategy(cls) -> List[ChunkStrategy]:
+        return [
+            ChunkStrategy.CHUNK_BY_SIZE,
+            ChunkStrategy.CHUNK_BY_SEPARATOR,
+        ]
+
+    @classmethod
+    def default_chunk_strategy(cls) -> ChunkStrategy:
+        return ChunkStrategy.CHUNK_BY_SIZE
+
+    @classmethod
+    def type(cls):
+        return KnowledgeType.URL