http.py 文件源码

def safe_urlopen(url, method=None, params=None, data=None, json=None,
                 headers=None, allow_redirects=False, timeout=30,
                 verify_ssl=True, user_agent=None):
    """
    A slightly safer version of ``urlib2.urlopen`` which prevents redirection
    and ensures the URL isn't attempting to hit a blacklisted IP range.
    """
    if user_agent is not None:
        warnings.warn('user_agent is no longer used with safe_urlopen')

    session = build_session()

    kwargs = {}

    if json:
        kwargs['json'] = json
        if not headers:
            headers = {}
        headers.setdefault('Content-Type', 'application/json')

    if data:
        kwargs['data'] = data

    if params:
        kwargs['params'] = params

    if headers:
        kwargs['headers'] = headers

    if method is None:
        method = 'POST' if (data or json) else 'GET'

    try:
        response = session.request(
            method=method,
            url=url,
            allow_redirects=allow_redirects,
            timeout=timeout,
            verify=verify_ssl,
            **kwargs
        )
    # Our version of requests does not transform ZeroReturnError into an
    # appropriately generically catchable exception
    except ZeroReturnError as exc:
        import sys
        exc_tb = sys.exc_info()[2]
        six.reraise(SSLError, exc, exc_tb)
        del exc_tb

    # requests' attempts to use chardet internally when no encoding is found
    # and we want to avoid that slow behavior
    if not response.encoding:
        response.encoding = 'utf-8'

    return response