英文:
Reading zip file content for later compute sha256 checksum fails
问题
我有一个包含一些常规文件的zip文件。这个文件已上传到文件服务器。
现在我正在尝试计算zip文件的sha256校验和，然后将校验和写入一个*.sha256sum文件，并将其上传到文件服务器。
然后，当有人从文件服务器下载zip文件和校验和文件（.sha256sum）时，他/她会再次计算zip文件的sha256并将其与存储为文本的校验和文件（.sha256sum）中刚下载的校验和进行比较。
当我尝试计算zip文件的sha256校验和时，出现错误。
with open(filename) as f:
data = f.read()
hash_sha256 = hashlib.sha256(data).hexdigest()
错误如下，并且在行data = f.read()中抛出：
in decode
return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap'编解码器无法解码位置44处的字节0x90：字符映射到<undefined>
英文:
I have a zip file which contains some regular files. This file is uploaded to a fileserver.
Now I am trying to compute the sha256 checksum for the zip file, then write the checksum into a *.sha256sum file and upload to the fileserver as well.
Then when one downloads the zip file and the checksum file (.sha256sum) from the fileserver, he/she computes again the sha256 of the zip file and compare it with the one stored as text in the checksum file (.sha256sum) just downloaded.
When I try to compute the sha256 checksum of the zip file i get an error.
with open(filename) as f:
data = f.read()
hash_sha256 = hashlib.sha256(data).hexdigest()
The error is the following and it is thrown in line data = f.read():
in decode
return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap' codec can't decode byte 0x90 in position 44: character maps to <undefined>
答案1
得分: 2
你必须以二进制模式打开文件：
with open(filename, 'rb') as f:
data = f.read()
hash_sha256 = hashlib.sha256(data).hexdigest()
根据读写文件文档：
通常情况下，文件以文本模式打开，这意味着您从文件中读取和写入字符串，这些字符串是以特定编码编码的。
因此，在底层进行了一些操作，以使其成为可用的文本，而您并不希望这样。
在模式后附加 'b' 将文件以二进制模式打开。二进制模式数据以字节对象读取和写入。
英文:
You must open the file in binary mode:
with open(filename, 'rb') as f:
data = f.read()
hash_sha256 = hashlib.sha256(data).hexdigest()
Per Reading and Writing files:
> Normally, files are opened in text mode, that means, you read and write strings from and to the file, which are encoded in a specific encoding.
So, there's something going on under the hood to make it usable text, which you don't want.
> Appending a 'b' to the mode opens the file in binary mode. Binary mode data is read and written as bytes objects.
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