SDK for session (#2354)

### What problem does this PR solve?

Includes SDK for creating, updating sessions, getting sessions, listing
sessions, and dialogues
#1102 
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

sdk/python/ragflow/modules/session.py

@@ -8,17 +8,17 @@ class Session(Base):
         self.id = None
         self.name = "New session"
         self.messages = [{"role": "assistant", "content": "Hi! I am your assistant，can I help you?"}]
-
         self.assistant_id = None
         super().__init__(rag, res_dict)
 
     def chat(self, question: str, stream: bool = False):
+        for message in self.messages:
+            if "reference" in message:
+                message.pop("reference")
         res = self.post("/session/completion",
-                        {"id": self.id, "question": question, "stream": stream, "messages": self.messages})
-        res = res.text
-        response_lines = res.splitlines()
-        message_list = []
-        for line in response_lines:
+                        {"id": self.id, "question": question, "stream": stream}, stream=True)
+        for line in res.iter_lines():
+            line = line.decode("utf-8")
             if line.startswith("data:"):
                 json_data = json.loads(line[5:])
                 if json_data["data"] != True:
@@ -26,26 +26,49 @@ class Session(Base):
                     reference = json_data["data"]["reference"]
                     temp_dict = {
                         "content": answer,
-                        "role": "assistant",
-                        "reference": reference
+                        "role": "assistant"
                     }
+                    if "chunks" in reference:
+                        chunks = reference["chunks"]
+                        chunk_list = []
+                        for chunk in chunks:
+                            new_chunk = {
+                                "id": chunk["chunk_id"],
+                                "content": chunk["content_with_weight"],
+                                "document_id": chunk["doc_id"],
+                                "document_name": chunk["docnm_kwd"],
+                                "knowledgebase_id": chunk["kb_id"],
+                                "image_id": chunk["img_id"],
+                                "similarity": chunk["similarity"],
+                                "vector_similarity": chunk["vector_similarity"],
+                                "term_similarity": chunk["term_similarity"],
+                                "positions": chunk["positions"],
+                            }
+                            chunk_list.append(new_chunk)
+                        temp_dict["reference"] = chunk_list
                     message = Message(self.rag, temp_dict)
-                    message_list.append(message)
-        return message_list
+                    yield message
 
     def save(self):
         res = self.post("/session/save",
-                        {"id": self.id, "dialog_id": self.assistant_id, "name": self.name, "message": self.messages})
+                        {"id": self.id, "assistant_id": self.assistant_id, "name": self.name})
         res = res.json()
         if res.get("retmsg") == "success": return True
         raise Exception(res.get("retmsg"))
 
+    def delete(self):
+        res = self.rm("/session/delete", {"id": self.id})
+        res = res.json()
+        if res.get("retmsg") == "success": return True
+        raise Exception(res.get("retmsg"))
+
+
 class Message(Base):
     def __init__(self, rag, res_dict):
-        self.content = "您好，我是您的助手小樱，长得可爱又善良，can I help you?"
-        self.reference = []
+        self.content = "Hi! I am your assistant，can I help you?"
+        self.reference = None
         self.role = "assistant"
-        self.prompt=None
+        self.prompt = None
         super().__init__(rag, res_dict)