使用Python C扩展时如何解决"UnicodeDecodeError:'utf-8'编解码器无法解码字节"的问题? [英] How to fix 'UnicodeDecodeError: 'utf-8' codec can't decode byte' when using Python C Extensions?

问题描述

给出以下文件 bug.txt :

event "øat" not handled

我在文件 fastfilewrapper.cpp

#include <Python.h>
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>

static PyObject* hello_world(PyObject *self, PyObject *args) {
    printf("Hello, world!\n");
    std::string retval;
    std::ifstream fileifstream;

    fileifstream.open("./bug.txt");
    std::getline( fileifstream, retval );
    fileifstream.close();
    std::cout << "retval " << retval << std::endl;
    return Py_BuildValue( "s", retval.c_str() );
}

static PyMethodDef hello_methods[] = { {
        "hello_world", hello_world, METH_NOARGS,
        "Print 'hello world' from a method defined in a C extension."
    },
    {NULL, NULL, 0, NULL}
};

static struct PyModuleDef hello_definition = {
    PyModuleDef_HEAD_INIT,
    "hello", "A Python module that prints 'hello world' from C code.",
    -1, hello_methods
};

PyMODINIT_FUNC PyInit_fastfilepackage(void) {
    Py_Initialize();
    return PyModule_Create(&hello_definition);
}

我使用 setup.py

from distutils.core import setup, Extension

# https://bugs.python.org/issue35893
from distutils.command import build_ext

def get_export_symbols(self, ext):
    parts = ext.name.split(".")
    if parts[-1] == "__init__":
        initfunc_name = "PyInit_" + parts[-2]
    else:
        initfunc_name = "PyInit_" + parts[-1]

build_ext.build_ext.get_export_symbols = get_export_symbols

setup(name='fastfilepackage', version='1.0',  \
      ext_modules=[Extension('fastfilepackage', ['fastfilewrapper.cpp'])])

然后，我使用以下 test.py 脚本:

Then, I use this test.py script:

import fastfilepackage

iterable = fastfilepackage.hello_world()
print('iterable', iterable)

但是当我运行 test.py Python脚本时，Python抛出此异常:

But Python throws this exception when I run the test.py Python Script:

$ PYTHONIOENCODING=utf8 python3 test.py
Hello, world!
retval event "▒at" not handled
Traceback (most recent call last):
  File "test.py", line 3, in <module>
    iterable = fastfilepackage.hello_world()
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xf8 in position 7: invalid start byte

如何从无效的Unicode字符中恢复?

How can I recover from invalid Unicode characters?

即绑定C和Python时忽略这些错误.

i.e., ignore these errors when binding C and Python.

仅在使用Python时，我可以使用它:

When purely working with Python, I can use this:

file_in = open( './bug.txt', errors='replace' )
line = file_in.read()
print( "The input line was: {line}".format(line=line) )

与 Python C扩展绑定时，等同于 errors ='replace'的是什么?

What is the equivalent to errors='replace' when binding with Python C Extensions?

推荐答案

如果您想使用'replace'错误处理语义，则应像这样在C端进行处理，并将其返回到python端:

If you want to have 'replace' error handling semantic you should do it on the C side like so and return it to the python side:

return PyUnicode_DecodeUTF8(retval.c_str(), retval.size(), "replace");

在我们的情况下，这会像:

This will give in our case sth like:

Hello, world!
retval event "?at" not handled
iterable event "�at" not handled

这篇关于使用Python C扩展时如何解决"UnicodeDecodeError:'utf-8'编解码器无法解码字节"的问题?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！