python挑战之level 19

连接： http://www.pythonchallenge.com/pc/hex/bin.html

登陆密码：（butter,fly)

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图片是印度大陆，上面很多文字，，看不清，应该是地名吧

标题：please!

注释：有很多

From: leopold.moz@pythonchallenge.com
Subject: what do you mean by "open the attachment?"
Mime-version: 1.0
Content-type: Multipart/mixed; boundary="===============1295515792=="

It is so much easier for you, youngsters.
Maybe my computer is out of order.
I have a real work to do and I must know what's inside!

<table><tbody><tr><td class="line-content"><span class="html-comment">--===============1295515792==</span></td></tr><tr><td class="line-number" value="25"> </td><td class="line-content"><span class="html-comment">Content-type: audio/x-wav; name="indian.wav"</span></td></tr><tr><td class="line-number" value="26"> </td><td class="line-content"><span class="html-comment">Content-transfer-encoding: base64</span></td></tr></tbody></table>

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百度一下：原来这是要我们从网页源码中给出了一封邮件，需要从附件生成一段音频文件进行音频的处理，播放音频，只有一个单词sorry，百度原来需要替换网址，发现提示：

 "what are you apologizing for?"

import base64
with open('first.txt','r') as f:
    data=f.read()
data_deb64=base64.b64decode(data)
with open('indian.wav','wb') as w:
    w.write(data_deb64)

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不知道该如何做了。看别人把这句话作为标题发给上面的邮箱，的到的回复是：

Never mind that.

Have you found my broken zip?

md5: bbb8b499a0eef99b52c7f13f4e78c24b

Can you believe what one mistake can lead to?

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百度了一下，看看别人的答案，原来是根据图片的颜色不一样，需要将wav文件反转，

import wave

wi = wave.open('indian.wav','rb')
wo = wave.open('indian_out.wav','wb')
#获取wav的(nchannels, sampwidth, framerate, nframes, comptype, compname)信息
wo.setparams(wi.getparams())
#根据声音的帧数，反转声音
for i in range(wi.getnframes()):

    wo.writeframes(wi.readframes(1)[::-1])  #读取一帧反转一帧
wi.close()
wo.close()

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录制视频的那个人使用的方法也不错，详细讲解了wav的构造，大家可以听听他的视频：

它使用的方法如下：

wi = open('indian.wav','rb')
wo = open('indian_out2.wav','wb')

data=wi.read()
wav_head,wav_data=data[:44],data[44:]
print(type(data[44:]))
print(type(data[44]))
print('%d'%(16+1))
#根据声音的帧数，反转声音
#chr(b2)+chr(b1)，是因为bi,b2现在是十进制，转化为二进制
reverse_data=''.join(chr(b2)+chr(b1) for (b1,b2) in zip(wav_data[0::2],wav_data[1::2]))
#添加头部和声音数据
wo.write(wav_head)
#需要写入bytes类型
wo.write(reverse_data.encode('utf-8'))

wi.close()
wo.close()

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结果为：you are an idiot

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