mirror of
https://github.com/hwchase17/langchain
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123 lines
3.9 KiB
Python
123 lines
3.9 KiB
Python
import base64
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import io
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from pathlib import Path
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from langchain.chat_models import ChatOpenAI
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from langchain.pydantic_v1 import BaseModel
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from langchain.schema.document import Document
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from langchain.schema.messages import HumanMessage
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from langchain.schema.output_parser import StrOutputParser
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from langchain.schema.runnable import RunnableLambda, RunnablePassthrough
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from langchain.vectorstores import Chroma
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from langchain_experimental.open_clip import OpenCLIPEmbeddings
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from PIL import Image
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def resize_base64_image(base64_string, size=(128, 128)):
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"""
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Resize an image encoded as a Base64 string.
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:param base64_string: A Base64 encoded string of the image to be resized.
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:param size: A tuple representing the new size (width, height) for the image.
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:return: A Base64 encoded string of the resized image.
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"""
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img_data = base64.b64decode(base64_string)
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img = Image.open(io.BytesIO(img_data))
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resized_img = img.resize(size, Image.LANCZOS)
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buffered = io.BytesIO()
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resized_img.save(buffered, format=img.format)
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return base64.b64encode(buffered.getvalue()).decode("utf-8")
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def get_resized_images(docs):
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"""
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Resize images from base64-encoded strings.
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:param docs: A list of base64-encoded image to be resized.
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:return: Dict containing a list of resized base64-encoded strings.
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"""
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b64_images = []
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for doc in docs:
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if isinstance(doc, Document):
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doc = doc.page_content
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resized_image = resize_base64_image(doc, size=(1280, 720))
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b64_images.append(resized_image)
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return {"images": b64_images}
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def img_prompt_func(data_dict, num_images=2):
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"""
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GPT-4V prompt for image analysis.
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:param data_dict: A dict with images and a user-provided question.
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:param num_images: Number of images to include in the prompt.
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:return: A list containing message objects for each image and the text prompt.
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"""
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messages = []
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if data_dict["context"]["images"]:
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for image in data_dict["context"]["images"][:num_images]:
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image_message = {
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"type": "image_url",
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"image_url": {"url": f"data:image/jpeg;base64,{image}"},
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}
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messages.append(image_message)
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text_message = {
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"type": "text",
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"text": (
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"You are an analyst tasked with answering questions about visual content.\n"
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"You will be give a set of image(s) from a slide deck / presentation.\n"
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"Use this information to answer the user question. \n"
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f"User-provided question: {data_dict['question']}\n\n"
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),
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}
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messages.append(text_message)
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return [HumanMessage(content=messages)]
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def multi_modal_rag_chain(retriever):
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"""
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Multi-modal RAG chain,
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:param retriever: A function that retrieves the necessary context for the model.
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:return: A chain of functions representing the multi-modal RAG process.
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"""
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# Initialize the multi-modal Large Language Model with specific parameters
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model = ChatOpenAI(temperature=0, model="gpt-4-vision-preview", max_tokens=1024)
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# Define the RAG pipeline
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chain = (
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{
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"context": retriever | RunnableLambda(get_resized_images),
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"question": RunnablePassthrough(),
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}
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| RunnableLambda(img_prompt_func)
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| model
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| StrOutputParser()
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)
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return chain
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# Load chroma
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vectorstore_mmembd = Chroma(
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collection_name="multi-modal-rag",
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persist_directory=str(Path(__file__).parent.parent / "chroma_db_multi_modal"),
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embedding_function=OpenCLIPEmbeddings(
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model_name="ViT-H-14", checkpoint="laion2b_s32b_b79k"
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),
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)
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# Make retriever
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retriever_mmembd = vectorstore_mmembd.as_retriever()
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# Create RAG chain
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chain = multi_modal_rag_chain(retriever_mmembd)
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# Add typing for input
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class Question(BaseModel):
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__root__: str
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chain = chain.with_types(input_type=Question)
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