Update app.py

app.py

@@ -21,14 +21,11 @@ system_template = """Use the following pieces of context to answer the users que
 If you don't know the answer, just say that you don't know, don't try to make up an answer.
 ALWAYS return a "SOURCES" part in your answer.
 The "SOURCES" part should be a reference to the source of the document from which you got your answer.
-
 Example of your response should be:
-
 ```
 The answer is foo
 SOURCES: xyz
 ```
-
 Begin!
 ----------------
 {summaries}"""
@@ -47,6 +44,9 @@ async def start():
         # path = r'assets/ChatPDFAvatar.jpg'
     ).send()
 
+
+@cl.langchain_factory(use_async=True)
+async def init():
     files = None
 
     # Wait for the user to upload a file
@@ -117,21 +117,14 @@ async def start():
     cl.user_session.set("texts", pages)
 
     # Let the user know that the system is ready
-    msg.content = f''' "{file.name}" processed. You can now ask questions!'''
-    await msg.update()
+    await msg.update(content=f''' "{file.name}" processed. You can now ask questions!''')
 
-    cl.user_session.set('chain', chain)
 
+    return chain
 
-@cl.on_message
-async def process_response(message):
-    chain = cl.user_session.get("chain")
-    cb = cl.AsyncLangchainCallbackHandler(
-        stream_final_answer=True, answer_prefix_tokens=["FINAL", "ANSWER"]
-    )
-    cb.answer_reached = True
-    res = await chain.acall(message, callbacks=[cb])
-    
+
+@cl.langchain_postprocess
+async def process_response(res):
     answer = res["answer"]
     source_documents = res['source_documents']
     content = [source_documents[i].page_content for i in range(len(source_documents))]
@@ -145,8 +138,5 @@ async def process_response(message):
     else:
         answer += "\n\nNo sources found"
     
-    if cb.has_streamed_final_answer:
-        cb.final_stream.elements = source_elements
-        await cb.final_stream.update()
-    else:
-        await cl.Message(content=answer, elements=source_elements).send()
+    await cl.Message(content=answer, elements=source_elements).send()
+    # await cl.Message(content=answer).send()