Python使用filetype精确判断文件类型

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

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  –  audio/mpeg
• 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
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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
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------