Python之基于十六进制判断文件类型

Posted 2020-11-22 小粉优化大师

核心代码：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Author  : suk
import struct
from io import BytesIO


# 支持文件类型
# 用16进制字符串的目的是可以知道文件头是多少字节
# 各种文件头的长度不一样，少则2字符，长则8字符
def typeList(types):
    type_dict = {\'jpg\': [\'FFD8FFE000104A464946\'],
                 \'png\': [\'89504E470D0A1A0A0000\'],
                 \'gif\': [\'47494638396126026F01\'],
                 \'tif\': [\'49492A00227105008037\'],
                 \'bmp\': [\'424D8E1B030000000000\'],
                 \'dwg\': [\'41433130313500000000\'],
                 \'html\': [\'3C21444F435459504520\'],
                 \'htm\': [\'3C21646F637479706520\'],
                 \'css\': [\'48544D4C207B0D0A0942\'],
                 \'js\': [\'696B2E71623D696B2E71\'],
                 \'rtf\': [\'7B5C727466315C616E73\'],
                 \'psd\': [\'38425053000100000000\'],
                 \'eml\': [\'46726F6D3A203D3F6762\'],
                 \'wps\': [\'D0CF11E0A1B11AE10000\'],
                 \'mdb\': [\'5374616E64617264204A\'],
                 \'ps\': \'[252150532D41646F6265]\',
                 \'pdf\': [\'255044462D312E\'],
                 \'rmvb\': [\'2E524D46000000120001\'],
                 \'flv\': [\'464C5601050000000900\'],
                 \'mp4\': [\'00000020667479706D70\'],
                 \'mp3\': [\'49443303000000002176\'],
                 \'mpg\': [\'000001BA210001000180\'],
                 \'wmv\': [\'3026B2758E66CF11A6D9\'],
                 \'wav\': [\'52494646E27807005741\'],
                 \'avi\': [\'52494646D07D60074156\'],
                 \'mid\': [\'4D546864000000060001\'],
                 \'zip\': [\'504B0304140000000800\', \'504B0304140000080800\', \'504B03040A0000080000\'],
                 \'rar\': [\'526172211A0700CF9073\'],
                 \'ini\': [\'235468697320636F6E66\'],
                 \'jar\': [\'504B03040A0000000000\'],
                 \'exe\': [\'4D5A9000030000000400\'],
                 \'jsp\': [\'3C25402070616765206C\'],
                 \'mf\': [\'4D616E69666573742D56\'],
                 \'xml\': [\'3C3F786D6C2076657273\'],
                 \'sql\': [\'494E5345525420494E54\'],
                 \'java\': [\'7061636B616765207765\'],
                 \'bat\': [\'406563686F206F66660D\'],
                 \'gz\': [\'1F8B0800000000000000\'],
                 \'properties\': [\'6C6F67346A2E726F6F74\'],
                 \'class\': [\'CAFEBABE0000002E0041\'],
                 \'chm\': [\'49545346030000006000\'],
                 \'mxp\': [\'04000000010000001300\'],
                 \'docx\': [\'504B0304140006000800\', \'504B03040A0000000000\'],
                 \'torrent\': [\'6431303A637265617465\'],
                 \'mov\': [\'6D6F6F76\'],
                 \'wpd\': [\'FF575043\'],
                 \'dbx\': [\'CFAD12FEC5FD746F\'],
                 \'pst\': [\'2142444E\'],
                 \'qdf\': [\'AC9EBD8F\'],
                 \'pwl\': [\'E3828596\'],
                 \'ram\': [\'2E7261FD\']
                 }
    ret = {}
    for k_hex, v_prefix in type_dict.items():
        if k_hex in types:
            ret[k_hex] = v_prefix
    return ret


# 字节码转16进制字符串
def bytes2hex(bytes):
    num = len(bytes)
    hexstr = u""
    for i in range(num):
        t = u"%x" % bytes[i]
        if len(t) % 2:
            hexstr += u"0"
        hexstr += t
    return hexstr.upper()


# 获取文件类型
def file_type(filename):
    binfile = open(filename, \'rb\')  # 必需二制字读取
    tl = typeList(types=["jpg", "zip", "docx"])
    ftype = None
    for type_name, hcode_list in tl.items():
        flag = False
        for hcode in hcode_list:
            numOfBytes = int(len(hcode) / 2)  # 需要读多少字节
            binfile.seek(0)  # 每次读取都要回到文件头，不然会一直往后读取
            hbytes = struct.unpack_from("B" * numOfBytes, binfile.read(numOfBytes))  # 一个 "B"表示一个字节
            f_hcode = bytes2hex(hbytes)  # 如果判断不出来，打印出这个值，往字典增加即可
            # print("上传数据流hex", s_hcode, \'=\', "代码字典hex", hcode)  # 如果判断不出来，打印出这个值，往字典增加即可
            if f_hcode == hcode:
                flag = True
                break
        if flag:
            ftype = type_name
            break
    binfile.close()
    return ftype


# 获取字节流类型
def stream_type(stream, types):
    """
    :param stream:流数据
    :param types:需要判断文件类型,格式:["jpg","jpn"]
    :return:
    """
    tl = typeList(types=types)
    ftype = None
    for type_name, hcode_list in tl.items():
        flag = False
        for hcode in hcode_list:
            numOfBytes = int(len(hcode) / 2)  # 需要读多少字节
            hbytes = struct.unpack_from("B" * numOfBytes, stream[0:numOfBytes])  # 一个 "B"表示一个字节
            s_hcode = bytes2hex(hbytes)
            # print("上传数据流hex", s_hcode, \'=\', "代码字典hex", hcode)  # 如果判断不出来，打印出这个值，往字典增加即可
            if s_hcode == hcode:
                flag = True
                break
        if flag:
            ftype = type_name
            break
    return ftype


def stream_split(stream, count=3):
    """
    主要处理流是分段获取的数据
    :param stream: 块流
    :param count: 取多少段合成来判断类型,默认三段
    :return:
    """
    block_stream = BytesIO()
    temp = 1
    for block in stream:
        block_stream.write(block)
        if temp == count:
            break
        temp += 1
    return block_stream.getvalue()

is_file_type.py

type_dict字典，根据自己上传的文件，来填写，数据来自互联网。

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基于Flask的上传示例

@index.route(\'/upload\', methods=[\'GET\', \'POST\'])
def upload():

    if request.method == \'GET\':
        return render_template(\'upload.html\')

    upload_obj = request.files.get(\'code_file\')

    if not upload_obj:
        return \'没有选择文件上传\'

    ret = stream_type(stream_split(upload_obj.stream), ["jpg", "png", "pdf"])

    if not ret:
        return \'上传失败，文件类型不匹配，类型必须 "jpg" or "png" or "pdf"\'

    file_name = upload_obj.filename
    upload_obj.save(os.path.join(\'files\', file_name))

    return \'上传文件成功\'

upload.html

{% extends \'layout.html\' %}
{% block content %}
<h1>上传代码</h1>
<form action="" method="post" enctype="multipart/form-data">
    <input type="file" name="code_file">
    <input type="submit" value="上传"></input>
</form>
{% endblock %}

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开始上传文件：

上传不在列表中的文件类型

 

 

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上传在列表中的文件类型