Add PDF chatbot application

app.py

@@ -1,7 +1,239 @@
 import gradio as gr
+import os
 
-def greet(name):
-    return "Hello " + name + "!!"
+from langchain.document_loaders import PyPDFLoader
+from langchain.text_splitter import RecursiveCharacterTextSplitter
+from langchain.vectorstores import Chroma
+from langchain.chains import ConversationalRetrievalChain
+from langchain.embeddings import HuggingFaceEmbeddings 
+from langchain.llms import HuggingFacePipeline
+from langchain.chains import ConversationChain
+from langchain.memory import ConversationBufferMemory
+from langchain.llms import HuggingFaceHub
 
-iface = gr.Interface(fn=greet, inputs="text", outputs="text")
-iface.launch()
+from transformers import AutoTokenizer
+import transformers
+import torch
+import tqdm 
+import accelerate
+
+
+default_persist_directory = './chroma_HF/'
+default_llm_name1 = "tiiuae/falcon-7b-instruct"
+default_llm_name2 = "google/flan-t5-xxl"
+default_llm_name3 = "mosaicml/mpt-7b-instruct"
+default_llm_name4 = "meta-llama/Llama-2-7b-chat-hf"
+default_llm_name5 = "mistralai/Mistral-7B-Instruct-v0.1"
+list_llm = [default_llm_name1, default_llm_name2, default_llm_name3, default_llm_name4, default_llm_name5]
+
+
+# Load PDF document and create doc splits
+def load_doc(list_file_path, chunk_size, chunk_overlap):
+    # Processing for one document only
+    # loader = PyPDFLoader(file_path)
+    # pages = loader.load()
+    loaders = [PyPDFLoader(x) for x in list_file_path]
+    pages = []
+    for loader in loaders:
+        pages.extend(loader.load())
+    # text_splitter = RecursiveCharacterTextSplitter(chunk_size = 600, chunk_overlap = 50)
+    text_splitter = RecursiveCharacterTextSplitter(
+        chunk_size = chunk_size, 
+        chunk_overlap = chunk_overlap)
+    doc_splits = text_splitter.split_documents(pages)
+    return doc_splits
+
+
+# Create vector database
+def create_db(splits):
+    embedding = HuggingFaceEmbeddings()
+    vectordb = Chroma.from_documents(
+        documents=splits,
+        embedding=embedding,
+        persist_directory=default_persist_directory
+    )
+    return vectordb
+
+
+# Load vector database
+def load_db():
+    embedding = HuggingFaceEmbeddings()
+    vectordb = Chroma(
+        persist_directory=default_persist_directory, 
+        embedding_function=embedding)
+    return vectordb
+
+
+# Initialize langchain LLM chain
+def initialize_llmchain(llm_model, temperature, max_tokens, top_k, vector_db, progress=gr.Progress()):
+    progress(0.1, desc="Initializing HF tokenizer...")
+    # HuggingFacePipeline uses local model
+    # Warning: it will download model locally...
+    # tokenizer=AutoTokenizer.from_pretrained(llm_model)
+    # progress(0.5, desc="Initializing HF pipeline...")
+    # pipeline=transformers.pipeline(
+    #     "text-generation",
+    #     model=llm_model,
+    #     tokenizer=tokenizer,
+    #     torch_dtype=torch.bfloat16,
+    #     trust_remote_code=True,
+    #     device_map="auto",
+    #     # max_length=1024,
+    #     max_new_tokens=max_tokens,
+    #     do_sample=True,
+    #     top_k=top_k,
+    #     num_return_sequences=1,
+    #     eos_token_id=tokenizer.eos_token_id
+    #     )
+    # llm = HuggingFacePipeline(pipeline=pipeline, model_kwargs={'temperature': temperature})
+    
+    # HuggingFaceHub uses HF inference endpoints
+    progress(0.5, desc="Initializing HF Hub...")
+    llm = HuggingFaceHub(
+        repo_id=llm_model, 
+        model_kwargs={"temperature": temperature, "max_new_tokens": max_tokens, "top_k": top_k}
+    )
+    
+    progress(0.5, desc="Defining buffer memory...")
+    memory = ConversationBufferMemory(
+        memory_key="chat_history",
+        return_messages=True
+    )
+    # retriever=vector_db.as_retriever(search_type="similarity", search_kwargs={'k': 3})
+    retriever=vector_db.as_retriever()
+    progress(0.8, desc="Defining retrieval chain...")
+    global qa_chain
+    qa_chain = ConversationalRetrievalChain.from_llm(
+        llm,
+        retriever=retriever,
+        chain_type="stuff", 
+        memory=memory,
+        # combine_docs_chain_kwargs={"prompt": your_prompt})
+        # return_source_documents=True,
+        # return_generated_question=True,
+        # verbose=True,
+    )
+    progress(0.9, desc="Done!")
+    # return qa_chain
+
+
+# Initialize all elements
+def initialize_database(list_file_obj, chunk_size, chunk_overlap, progress=gr.Progress()):
+    # Create list of documents (when valid)
+    #file_path = file_obj.name
+    list_file_path = [x.name for x in list_file_obj if x is not None]
+    print('list_file_path', list_file_path)
+    progress(0.25, desc="Loading document...")
+    # Load document and create splits
+    doc_splits = load_doc(list_file_path, chunk_size, chunk_overlap)
+    # Create or load Vector database
+    progress(0.5, desc="Generating vector database...")
+    # global vector_db
+    vector_db = create_db(doc_splits)
+    progress(0.9, desc="Done!")
+    return vector_db, "Complete!"
+    #return qa_chain
+
+
+def initialize_LLM(llm_option, llm_temperature, max_tokens, top_k, vector_db, progress=gr.Progress()):
+    print("llm_option",llm_option)
+    llm_name = list_llm[llm_option]
+    print("llm_name",llm_name)
+    initialize_llmchain(llm_name, llm_temperature, max_tokens, top_k, vector_db, progress)
+    return "Complete!"
+    #return qa_chain
+
+
+def format_chat_history(message, chat_history):
+    formatted_chat_history = []
+    for user_message, bot_message in chat_history:
+        formatted_chat_history.append(f"User: {user_message}")
+        formatted_chat_history.append(f"Assistant: {bot_message}")
+    return formatted_chat_history
+    
+
+def conversation(message, history):
+    formatted_chat_history = format_chat_history(message, history)
+    #print("formatted_chat_history",formatted_chat_history)
+   
+    # Generate response using QA chain
+    response = qa_chain({"question": message, "chat_history": formatted_chat_history})
+    # return response['answer']
+    
+    # Append user message and response to chat history
+    new_history = history + [(message, response["answer"])]
+    return gr.update(value=""), new_history        
+    
+
+def upload_file(file_obj):
+    list_file_path = []
+    for idx, file in enumerate(file_obj):
+        file_path = file_obj.name
+        list_file_path.append(file_path)
+    # print(file_path)
+    # initialize_database(file_path, progress)
+    return list_file_path
+
+
+def demo():
+    with gr.Blocks(theme="base") as demo:
+        vector_db = gr.Variable()
+        # qa_chain = gr.Variable()
+        
+        gr.Markdown(
+        """<center><h2> Document-based chatbot</center></h2>
+        <h3>Ask any questions about your PDF documents (single or multiple)</h3>
+        <i>Note: chatbot performs question-answering using Langchain and LLMs</i>
+        """)
+        with gr.Tab("Step 1 - Document pre-processing"):
+            with gr.Row():
+                document = gr.Files(height=100, file_count="multiple", file_types=["pdf"], interactive=True, label="Upload PDF Documents")
+                # upload_btn = gr.UploadButton("Loading document...", height=100, file_count="multiple", file_types=["pdf"], scale=1)
+            with gr.Row():
+                db_btn = gr.Radio(["ChromaDB"], label="Vector database", value = "ChromaDB", type="index", info="Choose your vector database")
+            with gr.Accordion("Advanced options - Text splitter", open=False):
+                with gr.Row():
+                    slider_chunk_size = gr.Slider(minimum = 100, maximum = 1000, value=600, step=20, label="Chunk size", info="Chunk size", interactive=True)
+                with gr.Row():
+                    slider_chunk_overlap = gr.Slider(minimum = 10, maximum = 200, value=50, step=10, label="Chunk overlap", info="Chunk overlap", interactive=True)
+            with gr.Row():
+                db_progress = gr.Textbox(label="Database Initialization", value="None")
+            with gr.Row():
+                db_btn = gr.Button("Generating vector database...")
+            
+        with gr.Tab("Step 2 - Initializing QA chain"):
+            with gr.Row():
+                llm_btn = gr.Radio(["falcon-7b-instruct", "flan-t5-xxl", "mpt-7b-instruct", "Llama-2-7b-chat-hf", "Mistral-7B-Instruct-v0.1"], \
+                    label="LLM", value = "falcon-7b-instruct", type="index", info="Choose your LLM model")
+            with gr.Accordion("Advanced options - LLM", open=False):
+                slider_temperature = gr.Slider(minimum = 0.0, maximum = 1.0, value=0.7, step=0.1, label="Temperature", info="Model temperature", interactive=True)
+                slider_maxtokens = gr.Slider(minimum = 256, maximum = 4096, value=1024, step=24, label="Max Tokens", info="Model max tokens", interactive=True)
+                slider_topk = gr.Slider(minimum = 1, maximum = 10, value=3, step=1, label="top-k samples", info="Model top-k samples", interactive=True)
+            with gr.Row():
+                llm_progress = gr.Textbox(value="None",label="QA chain Initialization")
+            with gr.Row():
+                qachain_btn = gr.Button("QA chain Initialization...")
+
+        with gr.Tab("Step 3 - Conversation"):
+            chatbot = gr.Chatbot(height=600)
+            with gr.Row():
+                msg = gr.Textbox(placeholder="Type message", container=True)
+            with gr.Row():
+                submit_btn = gr.Button("Submit")
+                clear_btn = gr.ClearButton([msg, chatbot])
+            
+        # Preprocessing events
+        #upload_btn.upload(upload_file, inputs=[upload_btn], outputs=[document])
+        db_btn.click(initialize_database, inputs=[document, slider_chunk_size, slider_chunk_overlap], outputs=[vector_db, db_progress])
+        qachain_btn.click(initialize_LLM, inputs=[llm_btn, slider_temperature, slider_maxtokens, slider_topk, vector_db], outputs=[llm_progress]).then(lambda: None, None, chatbot, queue=False)
+
+        # Chatbot events
+        msg.submit(conversation, [msg, chatbot], [msg, chatbot], queue=False)
+        submit_btn.click(conversation, inputs=[msg, chatbot], outputs=[msg, chatbot], queue=False)
+        clear_btn.click(lambda: None, None, chatbot, queue=False)
+    demo.queue(concurrency_count=20).launch(debug=True)
+
+
+if __name__ == "__main__":
+    demo()
+