Question

我有这段代码：

def __executeCommand(self, command: str, input: str = None) -> str:
    p = sub.Popen(command, stdout=sub.PIPE, stderr=sub.PIPE, stdin=sub.PIPE, universal_newlines=True)
    p.stdin.write(input)
    output, error = p.communicate()
    if (len(errors) > 0):
        raise EnvironmentError("Could not generate the key: " + error)
    elif (p.returncode != 0):
        raise EnvironmentError("Could not generate the key. Return Value: " + p.returncode)
    return output

我在行output, error = p.communicate()中得到了一个UnicodeDecodeError：

Traceback (most recent call last):
  File "C:\Python34\lib\threading.py", line 921, in _bootstrap_inner
    self.run()
  File "C:\Python34\lib\threading.py", line 869, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Python34\lib\subprocess.py", line 1170, in _readerthread
    buffer.append(fh.read())
  File "C:\Python34\lib\encodings\cp1252.py", line 23, in decode
    return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 27: character maps to <undefined>

我该如何解决这个问题？

Answer 1

univeral_newlines=True启用文字模式。使用locale.getpreferredencoding(False)字符编码将子进程输出（字节）解码为@cdosborn mentioned。

如果它不起作用，请提供encoding使用的实际command。和/或将错误处理程序（例如'ignore','surrogateescape', etc）指定为errors参数：

from subprocess import Popen, PIPE

def __executeCommand(self, command: str, input: str = None, 
                     encoding=None, errors='strict') -> str:
    text_mode = (encoding is None)
    with Popen(command, stdout=PIPE, stderr=PIPE, stdin=PIPE,
               universal_newlines=text_mode) as p:
        if input is not None and not text_mode:
            input = input.encode(encoding, errors) # convert to bytes
        output, err = p.communicate(input)
    if err or p.returncode != 0: 
        raise EnvironmentError("Could not generate the key. "
                               "Error: {}, Return Value: {}".format(
                                   ascii(err), p.returncode))
    return output if text_mode else output.decode(encoding, errors)

Answer 2

universal_newlines=true设置会导致出现错误来源的其他编码。

def __executeCommand(self, command: str, input: str = None) -> str:
    p = sub.Popen(command, stdout=sub.PIPE, stderr=sub.PIPE, stdin=sub.PIPE)
    output, error = p.communicate(input)
    if (len(errors) > 0):
        raise EnvironmentError("Could not generate the key: " + error)
    elif (p.returncode != 0):
        raise EnvironmentError("Could not generate the key. Return Value: " + p.returncode)
    return output

universal_newlines=true会根据输出结果进行编码：

python -c 'import locale; print locale.getpreferredencoding()'

当Python期望您的输入与上面的编码匹配时，Python会抛出错误，而是以不同的编码清楚地处理一个字节。

有关python 3.4 universal_newlines here。

的更多信息

Answer 3

如果您使用的是Python 3.6或更高版本，则可以通过更改以下行来修复错误：

p = sub.Popen(command, stdout=sub.PIPE, stderr=sub.PIPE, stdin=sub.PIPE, universal_newlines=True)

对此：

p = sub.Popen(command, stdout=sub.PIPE, stderr=sub.PIPE, stdin=sub.PIPE, encoding="utf-8", universal_newlines=True)

我在上面使用了UTF-8，但是您可以将其替换为所需的任何编码。

Popen.communicate（）抛出UnicodeDecodeError

3 个答案: