76c867fca4
- shared/ = portable Android-origin sources vendored from deferred/desktop-server (app/build.gradle.kts srcDir repointed; PlaybackController.kt excluded as Android-only) - backend/ = bundled-lite engine (SQLite + inline queue); .venv symlinked from the old checkout, PYTHONPATH pins THIS backend's code over any editable install - repoRoot() resolves this project dir (env SHONAR_REPO still wins); desktop-dev.sh watches shared/ + backend/ - Verified: :app:compileKotlin + :app:test green (23 tests); engine boots on :8010, self-migrates, /healthz ok
74 lines
2.1 KiB
Python
74 lines
2.1 KiB
Python
"""Audio format validation: declared MIME type vs magic bytes.
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Families decouple declared MIME aliases (audio/mp4 vs audio/m4a) from what
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the bytes actually are. The original file is stored exactly as uploaded —
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validation never rewrites it.
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"""
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from __future__ import annotations
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FAMILY_BY_MIME = {
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"audio/mp4": "mp4",
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"audio/m4a": "mp4",
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"audio/aac": "aac",
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"audio/wav": "wav",
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"audio/x-wav": "wav",
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"audio/ogg": "ogg",
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"audio/opus": "ogg",
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"audio/webm": "webm",
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"audio/mpeg": "mpeg",
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}
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EXT_BY_FAMILY = {
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"mp4": ".m4a",
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"aac": ".aac",
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"wav": ".wav",
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"ogg": ".ogg",
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"webm": ".webm",
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"mpeg": ".mp3",
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}
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def sniff_audio_family(data: bytes) -> str | None:
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"""Return the audio family from magic bytes, or None if unrecognized."""
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if len(data) >= 12:
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if data[4:8] == b"ftyp":
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return "mp4"
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if data[:4] == b"RIFF" and data[8:12] == b"WAVE":
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return "wav"
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if data[:4] == b"OggS":
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return "ogg"
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if data[:4] == b"\x1a\x45\xdf\xa3":
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return "webm"
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if data[:3] == b"ID3":
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return "mpeg"
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if len(data) >= 2 and data[0] == 0xFF and (data[1] & 0xF6) == 0xF0:
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# ADTS frame sync: AAC (also accepted as mpeg-family audio)
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return "aac"
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return None
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def declared_family(mime_type: str) -> str | None:
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return FAMILY_BY_MIME.get(mime_type.lower().split(";")[0].strip())
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def is_compatible(mime_type: str, data: bytes) -> bool:
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"""True when the declared MIME matches the sniffed magic bytes.
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mpeg and aac are treated as one family: Android records AAC in ADTS or
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in MP4 containers and MIME reporting around these is inconsistent.
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"""
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declared = declared_family(mime_type)
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sniffed = sniff_audio_family(data)
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if declared is None or sniffed is None:
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return False
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if {declared, sniffed} == {"mpeg", "aac"}:
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return True
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return declared == sniffed
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def extension_for(mime_type: str, data: bytes) -> str:
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sniffed = sniff_audio_family(data)
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if sniffed is not None:
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return EXT_BY_FAMILY[sniffed]
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return EXT_BY_FAMILY.get(declared_family(mime_type) or "", ".bin")
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