PHPとRustを組み合わせて音声ファイルをエンコードする話

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1. PHPͱRustΛ૊Έ߹ΘͤͯԻ੠ ϑΝΠϧΛΤϯίʔυ͢Δ࿩ PHPerKaigi 2020 LT @yaminoma_tw

2. Shumpei Urabe (@yaminoma_tw) ޷͖ͳϑϨʔϜϫʔΫ͸ BEAR.Sunday PHPerݟश͍

3. PHP FFIͷ͓͸ͳ͠

4. FFIͱ͸ʁ • PHPҎ֎ͷݴޠͰ࣮૷͞ΕͨωΠςΟϒίʔυΛݺͼग़͢͜ͱ ͕Ͱ͖Δ࢓૊Έ • FFI͸ωΠςΟϒ࣮ߦͳͷͰɺύϑΥʔϚϯεͷ޲্͕ظ଴Ͱ͖ Δ

5. PHP FFIͷྺ࢙ • Ҏલ͔ΒPECLͰFFIͷΤΫεςϯγϣϯ͸͋ͬͨ • ͔͠͠ɺ10೥Ҏ্ߋ৽͞Ε͍ͯͳ͍ঢ়گͰ์ஔ͞Ε͍ͯͨ

6. PHP FFIͷྺ࢙ • ͦ͜ͰZendࣾͷDmitry Stogovࢯ͸ɺlibffiΛ࢖֦ͬͨுΛ։ൃͨ͠ • 2019೥1݄ʹࢍ੒24ɺ൓ର15ͱ͍͏ൺֱతᷮࠩͰPHP 7.4΁ͷ࠾༻ ͕ܾ·Γɺ͜ͷ֦ு͕ແࣄPHP 7.4ʹऔΓࠐ·Εͨ

   • ͦͷ݁ՌɺPECLͷFFIΤΫεςϯγϣϯʹൺ΂ΔͱɺΠϯλʔϑΣ ΠεͷΈهड़͢Δ͚ͩͰग़དྷΔΑ͏ʹͳͬͨ

7. ຊ୊

8. PHPͰԻ੠ϑΝΠϧΛΤϯίʔυͯ͠ΈΔ • Ի੠ϑΝΠϧͷΤϯίʔυͱ͍͑͹FFmpeg͕ఆ൪Ͱ͋Δ • FFmpegͷίϚϯυΛexecͰୟ͘ͷ͸؆୯Ͱ͸͋Δ͕ɺexecͰ ࣮ߦͨ͘͠ͳ͍ͱ͖΋͋Δ • PHP୯ମͰԻ੠ϑΝΠϧΛΤϯίʔυͰ͖Δͱ௒ศརʂ

9. ͱ͍͏͜ͱͰ࡞Γ·ͨ͠

10. php-mp3-encoder • https://github.com/yaminoma/php-mp3-encoder • RustͰMP3ͷΤϯίʔμʔͰ͋Δlibmp3lameΛ࢖ͬͯɺWAVϑΝ Πϧ͔ΒMP3ʹΤϯίʔυ͢Δαϯϓϧ • ͜ͷlibmp3lame΋bindgenΛ࢖ͬͯRust͔ΒFFIͰݺͼग़͍ͯ͠Δ

11. ͘͠Έ

12. wavͷத਎Λ uint8_t* Ͱ౉͢ Τϯίʔυͨ͠ϑΝΠϧ໊Λ char* Ͱ౉͢

13. PHPͰFFIΛ༗ޮʹͯ͠ΈΔ git clone https://github.com/php/php-src.git cd php-src git checkout PHP-7.4 ./configure

    --with-ffi make

14. PHPͰFFIΛ༗ޮʹͯ͠ΈΔ • σϑΥϧτ͸ ffi.enable=preload ʹͳ͓ͬͯΓɺϓϦϩʔυΛ ߦͬͨؔ਺·ͨ͸CLIΠϯλʔϑΣΠεͰͷΈFFIػೳΛ࢖༻͢ Δ͜ͱ͕Մೳ • ffi.enable=trueʹ͢ΔͱɺશͯͷFFIͷػೳΛ࢖͏͜ͱ͕ग़དྷΔ

15. RustͰΤϯίʔυ͢Δ෦෼Λ࣮૷͢Δ #[no_mangle] pub extern "C" fn encode(data: *mut u8, length:

    u32) -> *const c_char { unsafe { let buf: &mut [u8] = core::slice::from_raw_parts_mut(data, length as usize); let mut ptr = io::Cursor::new(buf); let mut wav_reader = hound::WavReader::new(&mut ptr).unwrap(); let mut data = Vec::new(); for sample in wav_reader.samples() { match sample { Ok(smpl) => data.push(smpl), _ => panic!("failed"), } } let timestamp = Rational64::from_integer(0); let raw_frame = RawFrame { timestamp, data }; let mut encoder = Encoder::new(); let output_file_name = encoder.encode(raw_frame); return CString::new(output_file_name) .expect("failed") .into_raw(); } }

16. RustͰdylibΛϏϧυͯ͠PHPͰαʔϒ͢Δ $ cargo build --release $ php -d ffi.enable=1 -S

    localhost:8000 -t src

17. μΠφϛοΫϥΠϒϥϦΛಡΈࠐΉ $signature = "const char* encode(uint8_t *data, uint32_t length);"; return

    \FFI::cdef( $signature, __DIR__ . "/../target/ release/libmp3encoder.dylib");

18. freadͰϑΝΠϧΛಡΈऔΔ $file = $_FILES['audio_file']['tmp_name']; $handle = fopen($file, "rb"); $fsize =

    filesize($file); $value = fread($handle, $fsize);

19. FFIͷݺͼग़͠ͱ࣮ߦ $ffi = loadLibrary(); $length = \strlen($value); $buffer = FFI::new(FFI::arrayType($ffi->type('uint8_t'),

    [$length])); FFI::memcpy($buffer, $value, $length); $bufferPtr = FFI::cast($ffi->type('uint8_t*'), $buffer); $outputFileName = $ffi->encode($bufferPtr, $length);

20. ݁Ռ • 5෼ͷۂ͕େମ8ඵ͘Β͍Ͱม׵͕ऴΘͬͨ • PHPͷFFIͷυΩϡϝϯτ͕৘ใྔগͳͯ݁͘ߏۤ͠Μͩ • FFI͕༗ޮʹͳ͍ͬͯΕ͹ͲͷαʔόͰ΋MP3͕ΤϯίʔυͰ͖ Δʂ

21. FFIͷকདྷ • ܭࢉྔͷଟ͍ϓϩάϥϜΛFFIͰݺͼग़͢ͱྑ͍͔΋͠Εͳ͍ • ·ͩ·࣮ͩݧతͳཁૉ͕ଟ͍ͷͰɺϓϩμΫγϣϯϨσΟʔͰ ͸ͳ͍ • ͜Ε͔Βଞͷݴޠͱ૊Έ߹ΘͤͯPHP͕΋ͬͱ੝Γ্͕͍ͬͯ ͖͍ͨʂ

22. ͓͠·͍