Initial commit

backend/services/audiveris.py

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+"""
+Audiveris service: PDF/image to MusicXML via Audiveris.
+
+Audiveris is detected automatically in three locations (in order):
+  1. backend/bin/audiveris.jar  - legacy standalone JAR (any platform)
+  2. /Applications/Audiveris.app - macOS DMG install
+  3. `audiveris` in PATH        - Linux .deb / Windows .msi install
+
+Get Audiveris at: https://github.com/Audiveris/audiveris/releases
+Requires Java 17+ (already present on this machine).
+"""
+import asyncio
+import os
+import shutil
+import subprocess
+import tempfile
+from pathlib import Path
+
+# ── Audiveris binary detection ────────────────────────────────────────────────
+
+_LEGACY_JAR = Path(__file__).parent.parent / "bin" / "audiveris.jar"
+
+_MACOS_APP_BIN = Path("/Applications/Audiveris.app/Contents/MacOS/Audiveris")
+
+
+def _find_audiveris() -> list[str] | None:
+    """Return the command prefix to invoke Audiveris, or None if not found.
+
+    Checked in order:
+      1. backend/bin/audiveris.jar  (legacy standalone JAR)
+      2. /Applications/Audiveris.app  (macOS DMG install)
+      3. `audiveris` in PATH  (Linux deb / Windows msi)
+    """
+    if _LEGACY_JAR.exists():
+        return ["java", "-jar", str(_LEGACY_JAR)]
+    if _MACOS_APP_BIN.exists():
+        return [str(_MACOS_APP_BIN)]
+    if shutil.which("audiveris"):
+        return ["audiveris"]
+    return None
+
+
+# ── Timeouts (configurable via env vars) ──────────────────────────────────────
+
+# Audiveris: typically 30-120 s per page; set higher for very large scores.
+AUDIVERIS_TIMEOUT = int(os.environ.get("AUDIVERIS_TIMEOUT_S", "120"))
+
+# H4 - extension allowlist (defence-in-depth; routers also enforce this)
+_ALLOWED_SUFFIXES = {".pdf", ".png", ".jpg", ".jpeg", ".tiff", ".tif"}
+
+
+# ── Public async entry points ─────────────────────────────────────────────────
+
+async def pdf_to_musicxml(file_bytes: bytes, suffix: str = ".pdf") -> str:
+    """Run Audiveris OMR on a PDF or image, returns MusicXML string."""
+    return await asyncio.get_running_loop().run_in_executor(
+        None, _run_audiveris, file_bytes, suffix
+    )
+
+
+async def pdf_to_musicxml_and_midi(
+    file_bytes: bytes, suffix: str = ".pdf"
+) -> tuple[str, bytes]:
+    """OMR to MusicXML, then to MIDI.
+
+    Runs both steps in a single thread-pool task (both are blocking) to
+    avoid two executor round-trips and to keep the intermediate MusicXML
+    in memory rather than writing it back over the wire.
+
+    Returns:
+        (musicxml_str, midi_bytes)
+    """
+    return await asyncio.get_running_loop().run_in_executor(
+        None, _run_omr_and_convert, file_bytes, suffix
+    )
+
+
+# ── Combined OMR + MIDI conversion (blocking, runs in thread pool) ───────────
+
+def _run_omr_and_convert(file_bytes: bytes, suffix: str) -> tuple[str, bytes]:
+    musicxml = _run_audiveris(file_bytes, suffix)
+    # Import the private sync helper directly to avoid a second executor call.
+    from services.music21_svc import _xml_to_midi  # noqa: PLC0415
+    midi_bytes = _xml_to_midi(musicxml.encode("utf-8"), "score.xml")
+    return musicxml, midi_bytes
+
+
+# ── Audiveris (primary engine) ────────────────────────────────────────────────
+
+def _run_audiveris(file_bytes: bytes, suffix: str) -> str:
+    # H4 - validate suffix even if caller skips router-level check
+    if suffix.lower() not in _ALLOWED_SUFFIXES:
+        raise ValueError(f"Unsupported file type: {suffix!r}")
+
+    cmd_prefix = _find_audiveris()
+    if cmd_prefix is None:
+        # T3-2: generic message for the API consumer; full setup details are
+        # logged server-side only to avoid leaking OS/path information.
+        import logging as _log
+        _log.getLogger(__name__).error(
+            "Audiveris not found. Checked: %s, %s, PATH",
+            _LEGACY_JAR, _MACOS_APP_BIN,
+        )
+        raise RuntimeError("OMR engine is not available on this server")
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        input_path = Path(tmpdir) / f"input{suffix}"
+        input_path.write_bytes(file_bytes)
+        output_dir = Path(tmpdir) / "output"
+        output_dir.mkdir()
+
+        result = subprocess.run(
+            cmd_prefix + [
+                "-batch",
+                "-export",
+                "-output", str(output_dir),
+                "--", str(input_path),
+            ],
+            capture_output=True,
+            timeout=AUDIVERIS_TIMEOUT,
+        )
+
+        if result.returncode != 0:
+            # H3 - don't leak internal tool output in API response
+            raise RuntimeError("Audiveris OMR processing failed")
+
+        xml_files = list(output_dir.rglob("*.mxl")) + list(output_dir.rglob("*.xml"))
+        if not xml_files:
+            raise RuntimeError(
+                "Audiveris produced no MusicXML output. "
+                "The PDF may be a text document or a poor-quality scan."
+            )
+
+        result_path = xml_files[0]
+        if result_path.suffix.lower() == ".mxl":
+            # .mxl is a ZIP-compressed MusicXML - extract the main XML entry
+            import posixpath
+            import zipfile
+
+            def _safe_member(name: str) -> bool:
+                """Reject ZIP entry names with path traversal sequences."""
+                return not posixpath.normpath(name).startswith("..")
+
+            # T1-2: decompressed-size cap to defend against ZIP bombs.
+            # Don't trust ZipInfo.file_size (headers can lie); enforce
+            # the limit during actual streaming decompression.
+            MAX_DECOMPRESSED = 50 * 1024 * 1024  # 50 MB
+
+            with zipfile.ZipFile(result_path) as zf:
+                # META-INF/container.xml lists the root file; fall back to first .xml
+                names = zf.namelist()
+                root_file = next(
+                    (
+                        n for n in names
+                        if n.endswith(".xml")
+                        and not n.startswith("META-INF")
+                        and _safe_member(n)
+                    ),
+                    next(
+                        (n for n in names if n.endswith(".xml") and _safe_member(n)),
+                        None,
+                    ),
+                )
+                if root_file is None:
+                    raise RuntimeError("Audiveris .mxl archive contains no XML entry")
+
+                # Stream-read with size enforcement (T1-2)
+                with zf.open(root_file) as entry:
+                    chunks: list[bytes] = []
+                    total = 0
+                    while True:
+                        chunk = entry.read(65_536)
+                        if not chunk:
+                            break
+                        total += len(chunk)
+                        if total > MAX_DECOMPRESSED:
+                            raise ValueError(
+                                "Decompressed MusicXML exceeds 50 MB, possible ZIP bomb"
+                            )
+                        chunks.append(chunk)
+                    return b"".join(chunks).decode("utf-8")
+        else:
+            return result_path.read_text(encoding="utf-8")