Move code directly into backend and cli src

backend/src/server.py

@@ -0,0 +1,144 @@
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+from tempfile import TemporaryDirectory
+
+from fastapi import FastAPI, File, Form, HTTPException, UploadFile
+from fastapi.responses import Response
+
+SUPPORTED_FORMATS = {"txt", "vtt", "srt", "tsv", "json"}
+CONTENT_TYPES = {
+    "txt": "text/plain; charset=utf-8",
+    "vtt": "text/vtt; charset=utf-8",
+    "srt": "application/x-subrip; charset=utf-8",
+    "tsv": "text/tab-separated-values; charset=utf-8",
+    "json": "application/json; charset=utf-8",
+}
+
+app = FastAPI(title="whisper-remote-backend")
+
+
+def validate_output_format(output_format: str) -> str:
+    normalized = output_format.strip().lower()
+    if normalized not in SUPPORTED_FORMATS:
+        supported = ", ".join(sorted(SUPPORTED_FORMATS))
+        raise HTTPException(
+            status_code=400,
+            detail=f"Unsupported output format '{output_format}'. Supported formats: {supported}.",
+        )
+    return normalized
+
+
+def build_whisper_command(
+    *,
+    input_path: Path,
+    output_dir: Path,
+    model: str,
+    language: str | None,
+    output_format: str,
+) -> list[str]:
+    command = [
+        "whisper",
+        str(input_path),
+        "--model",
+        model,
+        "--output_format",
+        output_format,
+        "--output_dir",
+        str(output_dir),
+    ]
+    if language:
+        command.extend(["--language", language])
+    return command
+
+
+async def save_upload(upload: UploadFile, destination: Path) -> None:
+    with destination.open("wb") as handle:
+        while chunk := await upload.read(1024 * 1024):
+            handle.write(chunk)
+    await upload.close()
+
+
+def find_transcript_file(output_dir: Path, input_name: str, output_format: str) -> Path:
+    expected = output_dir / f"{Path(input_name).stem}.{output_format}"
+    if expected.exists():
+        return expected
+
+    matches = list(output_dir.glob(f"*.{output_format}"))
+    if len(matches) == 1:
+        return matches[0]
+
+    raise HTTPException(
+        status_code=500,
+        detail="Whisper finished without producing the expected output file.",
+    )
+
+
+@app.get("/health")
+def healthcheck() -> dict[str, str]:
+    return {"status": "ok"}
+
+
+@app.post("/transcriptions")
+async def transcribe(
+    file: UploadFile = File(...),
+    model: str = Form(...),
+    language: str | None = Form(default=None),
+    output_format: str = Form(...),
+) -> Response:
+    normalized_format = validate_output_format(output_format)
+    if not file.filename:
+        raise HTTPException(status_code=400, detail="Uploaded file must have a filename.")
+
+    with TemporaryDirectory(prefix="whisper-remote-upload-") as upload_root, TemporaryDirectory(
+        prefix="whisper-remote-output-"
+    ) as output_root:
+        input_path = Path(upload_root) / Path(file.filename).name
+        output_dir = Path(output_root)
+        await save_upload(file, input_path)
+
+        command = build_whisper_command(
+            input_path=input_path,
+            output_dir=output_dir,
+            model=model,
+            language=language,
+            output_format=normalized_format,
+        )
+
+        try:
+            completed = subprocess.run(
+                command,
+                check=False,
+                capture_output=True,
+                text=True,
+            )
+        except FileNotFoundError as exc:
+            raise HTTPException(
+                status_code=500,
+                detail="The 'whisper' CLI was not found on PATH on the backend host.",
+            ) from exc
+
+        if completed.returncode != 0:
+            detail = completed.stderr.strip() or completed.stdout.strip() or "Whisper CLI failed."
+            raise HTTPException(status_code=502, detail=detail)
+
+        transcript_path = find_transcript_file(output_dir, file.filename, normalized_format)
+        content = transcript_path.read_bytes()
+        download_name = f"{Path(file.filename).stem}.{normalized_format}"
+
+        return Response(
+            content=content,
+            media_type=CONTENT_TYPES[normalized_format],
+            headers={
+                "Content-Disposition": f'attachment; filename="{download_name}"',
+                "X-Whisper-Output-Format": normalized_format,
+                "X-Whisper-Model": model,
+            },
+        )
+
+
+def main() -> None:
+    import uvicorn
+
+    uvicorn.run("whisper_remote_backend.server:app", host="0.0.0.0", port=8000)