Python学习--- requests库中文编码问题

为什么会有ISO-8859-1这样的字符集编码

requests会从服务器返回的响应头的 Content-Type 去获取字符集编码，如果content-type有charset字段那么requests才能正确识别编码，否则就使用默认的 ISO-8859-1. 一般那些不规范的页面往往有这样的问题.

\requests\utils.py

def get_encoding_from_headers(headers):
    """Returns encodings from given HTTP Header Dict.

    :param headers: dictionary to extract encoding from.
    :rtype: str
    """

    content_type = headers.get('content-type')

    if not content_type:
        return None

    content_type, params = cgi.parse_header(content_type)

    if 'charset' in params:
        return params['charset'].strip("'\"")

    if 'text' in content_type:
        return 'ISO-8859-1'

如何获取正确的编码

requests的返回结果对象里有个apparent_encoding函数, apparent_encoding通过调用chardet.detect()来识别文本编码. 但是需要注意的是，这有些消耗计算资源.

\requests\models.py

    @property
    def apparent_encoding(self):
        """The apparent encoding, provided by the chardet library."""
        return chardet.detect(self.content)['encoding']

requests的text() 跟 content() 有什么区别？

requests在获取网络资源后，我们可以通过两种模式查看内容。 一个是r.text，另一个是r.content，那他们之间有什么区别呢？

分析requests的源代码发现，r.text返回的是处理过的Unicode型的数据，而使用r.content返回的是bytes型的原始数据。也就是说，r.content相对于r.text来说节省了计算资源，r.content是把内容bytes返回. 而r.text是decode成Unicode. 如果headers没有charset字符集的化,text()会调用chardet来计算字符集，这又是消耗cpu的事情.

通过看requests代码来分析text() content()的区别.

# r.text
@property
    def text(self):
        """Content of the response, in unicode.

        If Response.encoding is None, encoding will be guessed using
        ``chardet``.

        The encoding of the response content is determined based solely on HTTP
        headers, following RFC 2616 to the letter. If you can take advantage of
        non-HTTP knowledge to make a better guess at the encoding, you should
        set ``r.encoding`` appropriately before accessing this property.
        """

        # Try charset from content-type
        content = None
        encoding = self.encoding

        if not self.content:
            return str('')

        # Fallback to auto-detected encoding.
        if self.encoding is None:
            encoding = self.apparent_encoding

        # Decode unicode from given encoding.
        try:
            content = str(self.content, encoding, errors='replace')
        except (LookupError, TypeError):
            # A LookupError is raised if the encoding was not found which could
            # indicate a misspelling or similar mistake.
            #
            # A TypeError can be raised if encoding is None
            #
            # So we try blindly encoding.
            content = str(self.content, errors='replace')

        return content

# Content

@property
    def content(self):
        """Content of the response, in bytes."""

        if self._content is False:
            # Read the contents.
            if self._content_consumed:
                raise RuntimeError(
                    'The content for this response was already consumed')

            if self.status_code == 0 or self.raw is None:
                self._content = None
            else:
                self._content = bytes().join(self.iter_content(CONTENT_CHUNK_SIZE)) or bytes()

        self._content_consumed = True
        # don't need to release the connection; that's been handled by urllib3
        # since we exhausted the data.
        return self._content

requests中文乱码解决方法

方法一: 直接encode成utf-8格式.

r.content.decode(r.encoding).encode('utf-8')

r.encoding = 'utf-8'

方法二：如果headers头部没有charset，那么就从html的meta中抽取.