app.py

import gradio as gr
import requests

# Define the predict function that communicates with the FastAPI backend
def predict(num1, num2, operation):
    # API request to FastAPI backend
    response = requests.post("http://127.0.0.1:8000/calculate", 
                             json={"operation": operation, "num1": num1, "num2": num2})
    
    if response.status_code == 200:
        response_data = response.json()
        return response_data['result']
    elif (response.json())['detail'] == "Division by zero is not allowed":
        return "Error: Division by zero is not allowed"
    else:
        return "Error: Unable to connect to the FastAPI backend."

# Gradio Interface
demo = gr.Interface(
    fn=predict,
    inputs=[gr.Number(label="Number 1"), gr.Number(label="Number 2"), 
            gr.Dropdown(choices=["+", "-", "*", "/"], label="Operation")],
    outputs=gr.Textbox(label="Result"),
    title="Simple Calculator",
    allow_flagging="never"
)

# Launch the Gradio interface
demo.launch(share=True)

if __name__ == "__main__":
    import uvicorn
    import calc_fast_api
    uvicorn.run("calc_fast_api:app",host="127.0.0.1",port="8000")