main.py

import numpy as np
from qiskit import *

from typing import Union
from fastapi import FastAPI 
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from PIL import Image
from io import BytesIO
import os
from fastapi.middleware.cors import CORSMiddleware

app = FastAPI()

origins = [
    "*",
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

api_key = os.getenv("IBM_API_KEY")
IBMQ.save_account(api_key)
provider = IBMQ.load_account()

class Circuit(BaseModel):
    qasm: str

@app.post("/circuit/")
async def create_circuit(circuit: Circuit, backend_name: str | None = "ibmq_qasm_simulator"):
    circuit = QuantumCircuit.from_qasm_str(circuit.qasm)
    backend = provider.get_backend(backend_name)
    transpiled = transpile(circuit, backend=backend)
    job = backend.run(transpiled)
    return job.job_id()

@app.post("/draw")
async def create_circuit(circuit: Circuit):
    circuit = QuantumCircuit.from_qasm_str(circuit.qasm)
    drawn_image = circuit.draw(output="mpl")
    buffer = BytesIO()
    drawn_image.savefig(buffer, format="png")
    buffer.seek(0)

    return StreamingResponse(buffer, media_type="image/png")

@app.post("/result/{job_id}")
def get_result(job_id: str, backend_name: str | None = "ibmq_qasm_simulator"):
    job = provider.get_backend(backend_name).retrieve_job(job_id)
    result = job.result()
    data = {}
    counts = result.results[0].data.counts
    max_s = 0
    for k in counts.keys():
        max_s = max(max_s, len(bin(int(k, 16))[2:]))
    
    for k in counts.keys():
        data[(bin(int(k, 16))[2:]).ljust(max_s, "0")] = counts[k]
    return data