app.py

import gradio as gr
import os
import requests

SYSTEM_PROMPT = "As an LLM, your job is to generate detailed prompts that start with generate the image, for image generation models based on user input. Be descriptive and specific, but also make sure your prompts are clear and concise."
TITLE = "Image Prompter"
EXAMPLE_INPUT = "A Man Riding A Horse in Space"

HF_TOKEN = os.getenv("HF_TOKEN")
HEADERS = {"Authorization": f"Bearer {HF_TOKEN}"}

def build_input_prompt(message, chatbot, system_prompt):
    """
    Constructs the input prompt string from the chatbot interactions and the current message.
    """
    input_prompt = " \n" + system_prompt + " \n \n"
    for interaction in chatbot:
        input_prompt = input_prompt + str(interaction[0]) + " \n \n" + str(interaction[1]) + "\n \n \n"

    input_prompt = input_prompt + str(message) + " \n "
    return input_prompt


def post_request(model_url, payload):
    """
    Sends a POST request to the specified model URL and returns the JSON response.
    """
    response = requests.post(model_url, headers=HEADERS, json=payload)
    response.raise_for_status()  # Will raise an HTTPError if the HTTP request returned an unsuccessful status code
    return response.json()


def predict(model_url, message, chatbot=[], system_prompt=""):
    input_prompt = build_input_prompt(message, chatbot, system_prompt)
    data = {
        "inputs": input_prompt
    }

    try:
        response_data = post_request(model_url, data)
        json_obj = response_data[0]
        
        if 'generated_text' in json_obj and len(json_obj['generated_text']) > 0:
            bot_message = json_obj['generated_text']
            return bot_message
        elif 'error' in json_obj:
            raise gr.Error(json_obj['error'] +'Please refresh and try again with smaller input prompt')
        else:
            warning_msg = f"Unexpected response: {json_obj}"
            raise gr.Error(warning_msg)
    except requests.HTTPError as e:
        error_msg = f"Request failed with status code {e.response.status_code}"
        raise gr.Error(error_msg)
    except json.JSONDecodeError as e:
        error_msg = f"Failed to decode response as JSON: {str(e)}"
        raise gr.Error(error_msg)


def test_preview_chatbot(message, history, model_url):
    response = predict(model_url, message, history, SYSTEM_PROMPT)
    text_start = response.rfind(" ", ) + len(" ")
    response = response[text_start:]
    return response


welcome_preview_message = f"""
Expand your imagination and broaden your horizons with LLM. Welcome to **{TITLE}**!:\nThis is a chatbot that can generate detailed prompts for image generation models based on simple and short user input.\nSay something like: 
"{EXAMPLE_INPUT}"
"""

model_url_input = gr.Textbox(label="Model URL", value="https://huggingface.co/chat/models/meta-llama/Meta-Llama-3-70B-Instruct")
chatbot_preview = gr.Chatbot(layout="panel", value=[(None, welcome_preview_message)])
textbox_preview = gr.Textbox(scale=7, container=False, value=EXAMPLE_INPUT)

demo = gr.Interface(
    fn=test_preview_chatbot, 
    inputs=["text", "state", "text"], 
    outputs="text", 
    title=TITLE, 
    description="Image Prompter"
)

demo.launch()