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Python使用filetype精確判斷文件類型

更新時(shí)間：2017年07月02日 09:16:27 作者：lon.y@qq.com

判斷文件類型在開發(fā)中非常常見的需求，怎樣才能準(zhǔn)確的判斷文件類型呢？首先大家想到的是文件的后綴，但是非常遺憾的是這種方法是非常不靠譜的，因?yàn)槲募暮缶Y是可以隨意更改的，而python中有個(gè)小插件可以實(shí)現(xiàn)，下面我們就來詳細(xì)探討下

filetype.py

Small and dependency free Python package to infer file type and MIME type checking the magic numbers signature of a file or buffer.

This is a Python port from filetype Go package. Works in Python +3 .

一個(gè)小巧自由開放Python開發(fā)包，主要用來獲得文件類型。包要求Python 3.+

功能特色

•簡(jiǎn)單友好的API
•支持寬范圍文件類型
•提供文件擴(kuò)展名和MIME類型判斷
•文件的MIME類型擴(kuò)展新增
•通過文件（圖像、視頻、音頻…）簡(jiǎn)單分析
•可插拔：添加新的自定義類型的匹配
•快，即使處理大文件
•只需要前261個(gè)字節(jié)表示的最大文件頭，這樣你就可以通過一個(gè)單字節(jié)
•依賴自由（只是Python代碼，沒有C的擴(kuò)展，沒有l(wèi)ibmagic綁定）
•跨平臺(tái)文件識(shí)別

安裝

pip install filetype

API

詳情請(qǐng)查看 annotated API reference .

實(shí)例

簡(jiǎn)單的文件類型識(shí)別

import filetype
 
def main():
 kind = filetype.guess('tests/fixtures/sample.jpg')
 if kind is None:
  print('Cannot guess file type!')
  return
 
 print('File extension: %s' % kind.extension)
 print('File MIME type: %s' % kind.mime)
 
if __name__ == '__main__':
 main()

支持類型

圖片

• jpg – image/jpeg
• png – image/png
• gif – image/gif
• webp – image/webp
• cr2 – image/x-canon-cr2
• tif – image/tiff
• bmp – image/bmp
• jxr – image/vnd.ms-photo
• psd – image/vnd.adobe.photoshop
• ico – image/x-icon

視頻

• mp4 – video/mp4
• m4v – video/x-m4v
• mkv – video/x-matroska
• webm – video/webm
• mov – video/quicktime
• avi – video/x-msvideo
• wmv – video/x-ms-wmv
• mpg – video/mpeg
• flv – video/x-flv

音頻

• mid – audio/midi
• mp3 – audio/mpeg
• m4a – audio/m4a
• ogg – audio/ogg
• flac – audio/x-flac
• wav – audio/x-wav
• amr – audio/amr

資料庫

• epub – application/epub+zip
• zip – application/zip
• tar – application/x-tar
• rar – application/x-rar-compressed
• gz – application/gzip
• bz2 – application/x-bzip2
• 7z – application/x-7z-compressed
• xz – application/x-xz
• pdf – application/pdf
• exe – application/x-msdownload
• swf – application/x-shockwave-flash
• rtf – application/rtf
• eot – application/octet-stream
• ps – application/postscript
• sqlite – application/x-sqlite3
• nes – application/x-nintendo-nes-rom
• crx – application/x-google-chrome-extension
• cab – application/vnd.ms-cab-compressed
• deb – application/x-deb
• ar – application/x-unix-archive
• Z – application/x-compress
• lz – application/x-lzip

字體

• woff – application/font-woff
• woff2 – application/font-woff
• ttf – application/font-sfnt
• otf – application/font-sfnt

基準(zhǔn)測(cè)試

使用鏈接中的文件進(jìn)行測(cè)試，你可以點(diǎn)擊獲得到它： real files .

Environment: OSX x64 i7 2.7 Ghz
------------------------------------------------------------------------------------------ benchmark: 7 tests ------------------------------------------------------------------------------------------
Name (time in ns)                       Min                     Max                   Mean                StdDev                 Median                   IQR            Outliers(*) Rounds Iterations
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
test_infer_image_from_bytes        357.6279 (1.0)       29,166.5395 (1.0)       1,642.3360 (1.0)        380.9934 (1.0)       1,509.9843 (1.0)        158.9457 (1.0)       9095;13752 102301           6
test_infer_audio_from_bytes        953.6743 (2.67)      96,082.6874 (3.29)     16,534.5880 (10.07)    3,002.1143 (7.88)     15,974.0448 (10.58)      953.6743 (6.00)       4514;6051   41528           1
test_infer_video_from_bytes     13,828.2776 (38.67)    272,989.2731 (9.36)     16,151.3144 (9.83)     3,361.2320 (8.82)     15,020.3705 (9.95)       953.6743 (6.00)       2522;2887   22193           1
test_infer_image_from_disk      15,974.0448 (44.67)    108,957.2906 (3.74)     18,621.0844 (11.34)    3,895.4441 (10.22)    17,166.1377 (11.37)    1,192.0929 (7.50)       1528;1804   10206           1
test_infer_video_from_disk      23,841.8579 (66.67)    229,120.2545 (7.86)     28,691.3476 (17.47)    6,242.9901 (16.39)    25,987.6251 (17.21)    4,053.1158 (25.50)      1987;1247   15651           1
test_infer_zip_from_disk        26,941.2994 (75.33)    230,073.9288 (7.89)     32,123.3861 (19.56)    7,524.4988 (19.75)    29,087.0667 (19.26)    4,768.3716 (30.00)      1349;1292   16132           1
test_infer_tar_from_disk        33,855.4382 (94.67)    164,031.9824 (5.62)     36,884.4401 (22.46)    4,489.4443 (11.78)    36,001.2054 (23.84)      953.6743 (6.00)       1036;1828   14666           1
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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