app.py

import gradio as gr
from gradio_pdf import PDF
from qdrant_client import models, QdrantClient
from sentence_transformers import SentenceTransformer
from PyPDF2 import PdfReader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.callbacks.manager import CallbackManager
from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
# from langchain.llms import LlamaCpp
from langchain.vectorstores import Qdrant
from qdrant_client.http import models
# from langchain.llms import CTransformers
from ctransformers import AutoModelForCausalLM


# loading the embedding model - 

encoder = SentenceTransformer('jinaai/jina-embedding-b-en-v1')

print("embedding model loaded.............................")
print("####################################################")

# loading the LLM 

callback_manager = CallbackManager([StreamingStdOutCallbackHandler()])

print("loading the LLM......................................")

# llm = LlamaCpp(
#     model_path="./llama-2-7b-chat.Q3_K_S.gguf",
#     temperature = 0.2,
#     n_ctx=2048,
#     f16_kv=True,  # MUST set to True, otherwise you will run into problem after a couple of calls
#     max_tokens = 500,
#     callback_manager=callback_manager,
#     verbose=True,
# )

llm = AutoModelForCausalLM.from_pretrained("TheBloke/Llama-2-7B-Chat-GGUF", 
                                           model_file="llama-2-7b-chat.Q3_K_S.gguf", 
                                           model_type="llama", 
                                           temperature = 0.2,
                                           repetition_penalty = 1.5,
                                           max_new_tokens = 300,
                                           )



print("LLM loaded........................................")
print("################################################################")

# def get_chunks(text):
#     text_splitter = RecursiveCharacterTextSplitter(
#         # seperator = "\n",
#         chunk_size = 250,
#         chunk_overlap = 50,
#         length_function = len,
#     )

#     chunks = text_splitter.split_text(text)
#     return chunks


# pdf_path = './100 Weird Facts About the Human Body.pdf'


# reader = PdfReader(pdf_path)
# text = ""
# num_of_pages = len(reader.pages)

# for page in range(num_of_pages):
#     current_page = reader.pages[page]
#     text += current_page.extract_text()


# chunks = get_chunks(text)
# print(chunks)
# print("Chunks are ready.....................................")
# print("######################################################")

# client = QdrantClient(path = "./db")
# print("db  created................................................")
# print("#####################################################################")

# client.recreate_collection(
#     collection_name="my_facts",
#     vectors_config=models.VectorParams(
#         size=encoder.get_sentence_embedding_dimension(),  # Vector size is defined by used model
#         distance=models.Distance.COSINE,
#     ),
# )

# print("Collection created........................................")
# print("#########################################################")



# li = []
# for i in range(len(chunks)):
#     li.append(i)
 
# dic = zip(li, chunks)
# dic= dict(dic)

# client.upload_records(
#     collection_name="my_facts",
#     records=[
#         models.Record(
#             id=idx,
#             vector=encoder.encode(dic[idx]).tolist(),
#             payload= {dic[idx][:5] : dic[idx]}
#         ) for idx in dic.keys()
#     ],
# )

# print("Records uploaded........................................")
# print("###########################################################")

def chat(file, question):
    def get_chunks(text):
        text_splitter = RecursiveCharacterTextSplitter(
            # seperator = "\n",
            chunk_size = 250,
            chunk_overlap = 50,
            length_function = len,
        )

        chunks = text_splitter.split_text(text)
        return chunks


    pdf_path = file


    reader = PdfReader(pdf_path)
    text = ""
    num_of_pages = len(reader.pages)

    for page in range(num_of_pages):
        current_page = reader.pages[page]
        text += current_page.extract_text()


    chunks = get_chunks(text)
    print(chunks)
    print("Chunks are ready.....................................")
    print("######################################################")

    client = QdrantClient(path = "./db")
    print("db  created................................................")
    print("#####################################################################")

    client.recreate_collection(
        collection_name="my_facts",
        vectors_config=models.VectorParams(
            size=encoder.get_sentence_embedding_dimension(),  # Vector size is defined by used model
            distance=models.Distance.COSINE,
        ),
    )

    print("Collection created........................................")
    print("#########################################################")



    li = []
    for i in range(len(chunks)):
        li.append(i)
 
    dic = zip(li, chunks)
    dic= dict(dic)

    client.upload_records(
        collection_name="my_facts",
        records=[
            models.Record(
                id=idx,
                vector=encoder.encode(dic[idx]).tolist(),
                payload= {dic[idx][:5] : dic[idx]}
            ) for idx in dic.keys()
        ],
    )

    print("Records uploaded........................................")
    print("###########################################################")


    hits = client.search(
        collection_name="my_facts",
        query_vector=encoder.encode(question).tolist(),
        limit=3
    )
    context = []
    for hit in hits:
      context.append(list(hit.payload.values())[0])
    
    context = context[0] + context[1] + context[2]

    system_prompt = """You are a helpful assistant, you will use the provided context to answer user questions.
    Read the given context before answering questions and think step by step. If you can not answer a user question based on 
    the provided context, inform the user. Do not use any other information for answering user. Provide a detailed answer to the question."""


    B_INST, E_INST = "[INST]", "[/INST]"

    B_SYS, E_SYS = "<<SYS>>\n", "\n<</SYS>>\n\n"

    SYSTEM_PROMPT = B_SYS + system_prompt + E_SYS

    instruction = f""" 
    Context: {context}
    User: {question}"""

    prompt_template = B_INST + SYSTEM_PROMPT + instruction + E_INST
    print(prompt_template)
    result = llm(prompt_template)
    return result 


screen = gr.Interface(
    fn = chat,
    inputs = [PDF(label="Upload a PDF", interactive=True), gr.Textbox(lines = 10, placeholder = "Enter your question here 👉")],
    outputs = gr.Textbox(lines = 10, placeholder = "Your answer will be here soon 🚀"),
    title="Q&A with PDF 👩🏻‍💻📓✍🏻💡",
description="This app facilitates a conversation with PDFs available on https://www.delo.si/assets/media/other/20110728/100%20Weird%20Facts%20About%20the%20Human%20Body.pdf💡",
    theme="soft",
    # examples=["Hello", "what is the speed of human nerve impulses?"],
)

screen.launch()