判断文件类型在开发中非常常见的需求，怎样才能准确的判断文件类型呢？首先大家想到的是文件的后缀，但是非常遗憾的是这种方法是非常不靠谱的，因为文件的后缀是可以随意更改的，而python中有个小插件可以实现，下面我们就来详细探讨下
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 .
一个小巧自由开放Python开发包，主要用来获得文件类型。包要求Python 3.
功能特色
•简单友好的API
•支持宽范围文件类型
•提供文件扩展名和MIME类型判断
•文件的MIME类型扩展新增
•通过文件（图像、视频、音频…）简单分析
•可插拔：添加新的自定义类型的匹配
•快，即使处理大文件
•只需要前261个字节表示的最大文件头，这样你就可以通过一个单字节
•依赖自由（只是Python代码，没有C的扩展，没有libmagic绑定）
•跨平台文件识别
安装
pip install filetype
API
详情请查看 annotated API reference .
实例
简单的文件类型识别
importfiletype
defmain():
kind=filetype.guess('tests/fixtures/sample.jpg')
ifkindisNone:
print('Cannot guess file type!')
return
print('File extension: %s'%kind.extension)
print('File MIME type: %s'%kind.mime)
if__name__=='__main__':
main()
支持类型
图片
• 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
视频
• 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
音频
• mid – audio/midi
• mp3 –
• m4a – audio/m4a
• ogg – audio/ogg
• flac – audio/x-flac
• wav – audio/x-wav
• amr – audio/amr
资料库
• 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
字体
• woff – application/font-woff
• woff2 – application/font-woff
• ttf – application/font-sfnt
• otf – application/font-sfnt
基准测试
使用链接中的文件进行测试，你可以点击获得到它： 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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