app.py

import os
import uuid
import subprocess
import requests
import base64
from urllib.parse import urlparse
from fastapi import FastAPI, HTTPException
from fastapi.responses import JSONResponse, HTMLResponse

app = FastAPI()

# Base directory to store task files
BASE_DIR = "tasks"
os.makedirs(BASE_DIR, exist_ok=True)

def add_status(log_list, message):
    log_list.append(message)
    print(message)  # Also log to console

@app.post("/process")
def process_audio(payload: dict):
    status_log = []
    
    # Validate input
    if "url" not in payload:
        raise HTTPException(status_code=400, detail="Missing 'url' in payload")
    
    audio_url = payload["url"]
    add_status(status_log, "Received URL from payload.")
    
    # Create a unique task directory
    task_id = str(uuid.uuid4())
    task_dir = os.path.join(BASE_DIR, task_id)
    os.makedirs(task_dir, exist_ok=True)
    add_status(status_log, f"Created task directory: {task_dir}")
    
    # Check FFmpeg version
    try:
        ffmpeg_ver = subprocess.run(
            ["ffmpeg", "-version"],
            capture_output=True,
            text=True,
            check=True,
        )
        first_line = ffmpeg_ver.stdout.splitlines()[0]
        add_status(status_log, f"FFmpeg version: {first_line}")
    except Exception as e:
        add_status(status_log, f"Failed to get FFmpeg version: {e}")
        return JSONResponse(status_code=500, content={"status": status_log})
    
    # Check Spleeter version
    try:
        spleeter_ver = subprocess.run(
            ["spleeter", "--version"],
            capture_output=True,
            text=True,
            check=True,
        )
        add_status(status_log, f"Spleeter version: {spleeter_ver.stdout.strip()}")
    except Exception as e:
        add_status(status_log, f"Failed to get Spleeter version: {e}")
        return JSONResponse(status_code=500, content={"status": status_log})
    
    # Download the audio file
    try:
        r = requests.get(audio_url)
        r.raise_for_status()
        add_status(status_log, "Successfully downloaded audio file.")
    except Exception as e:
        add_status(status_log, f"Error downloading file: {e}")
        return JSONResponse(status_code=400, content={"status": status_log})
    
    # Clean filename: remove query parameters using urlparse
    parsed = urlparse(audio_url)
    path = parsed.path
    ext = os.path.splitext(path)[1] or ".mp3"
    input_filename = f"input{ext}"
    input_filepath = os.path.join(task_dir, input_filename)
    
    try:
        with open(input_filepath, "wb") as f:
            f.write(r.content)
        add_status(status_log, f"Saved audio file to: {input_filepath}")
    except Exception as e:
        add_status(status_log, f"Error saving file: {e}")
        return JSONResponse(status_code=500, content={"status": status_log})
    
    if not os.path.exists(input_filepath):
        add_status(status_log, "Error: Input file does not exist after download.")
        return JSONResponse(status_code=500, content={"status": status_log})
    
    # Run Spleeter using the updated syntax:
    # spleeter separate -p spleeter:2stems -o <task_dir> <input_filepath>
    spleeter_cmd = [
        "spleeter", "separate",
        "-p", "spleeter:2stems",
        "-o", task_dir,
        input_filepath
    ]
    add_status(status_log, "Running Spleeter command: " + " ".join(spleeter_cmd))
    
    try:
        result = subprocess.run(spleeter_cmd, capture_output=True, text=True, check=True)
        add_status(status_log, "Spleeter command output: " + result.stdout)
    except subprocess.CalledProcessError as e:
        add_status(status_log, "Spleeter processing failed: " + e.stderr)
        return JSONResponse(status_code=500, content={"status": status_log})
    
    # Spleeter creates an output folder with the base name of the input file.
    base_name = os.path.splitext(input_filename)[0]
    output_folder = os.path.join(task_dir, base_name)
    vocals_file = os.path.join(output_folder, "vocals.wav")
    accompaniment_file = os.path.join(output_folder, "accompaniment.wav")
    
    if not (os.path.exists(vocals_file) and os.path.exists(accompaniment_file)):
        add_status(status_log, "Error: Output files not found after processing.")
        return JSONResponse(status_code=500, content={"status": status_log})
    
    add_status(status_log, "Spleeter processing completed successfully.")
    
    # Read output files and encode them in base64
    try:
        with open(vocals_file, "rb") as f:
            vocals_data = f.read()
        with open(accompaniment_file, "rb") as f:
            accomp_data = f.read()
        vocals_b64 = base64.b64encode(vocals_data).decode("utf-8")
        accomp_b64 = base64.b64encode(accomp_data).decode("utf-8")
    except Exception as e:
        add_status(status_log, f"Error reading output files: {e}")
        return JSONResponse(status_code=500, content={"status": status_log})
    
    return JSONResponse(content={
        "task_id": task_id,
        "vocals": vocals_b64,
        "accompaniment": accomp_b64,
        "status": status_log
    })

@app.get("/", response_class=HTMLResponse)
def index():
    html_content = """
    <!DOCTYPE html>
    <html>
    <head>
        <title>Spleeter Processing Test</title>
    </head>
    <body>
        <h1>Spleeter Processing Test</h1>
        <form id="spleeterForm">
            Audio URL: <input type="text" name="url" size="50"/><br/><br/>
            <button type="submit">Process Audio</button>
        </form>
        <div id="result" style="margin-top:20px;"></div>
        <script>
            const form = document.getElementById('spleeterForm');
            form.onsubmit = async (e) => {
                e.preventDefault();
                const formData = new FormData(form);
                const url = formData.get('url');
                const response = await fetch('/process', {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json' },
                    body: JSON.stringify({ url })
                });
                const data = await response.json();
                let resultHTML = "<h3>Status Log:</h3><ul>";
                for (const log of data.status) {
                    resultHTML += "<li>" + log + "</li>";
                }
                resultHTML += "</ul>";
                if (data.vocals && data.accompaniment) {
                    const vocalsDataURI = "data:audio/wav;base64," + data.vocals;
                    const accompDataURI = "data:audio/wav;base64," + data.accompaniment;
                    resultHTML += "<h3>Vocals</h3>";
                    resultHTML += "<audio controls src='" + vocalsDataURI + "'></audio>";
                    resultHTML += "<h3>Accompaniment</h3>";
                    resultHTML += "<audio controls src='" + accompDataURI + "'></audio>";
                }
                if(data.task_id) {
                    resultHTML += `<p>Task ID: ${data.task_id}</p>`;
                }
                document.getElementById('result').innerHTML = resultHTML;
            };
        </script>
    </body>
    </html>
    """
    return HTMLResponse(content=html_content)