使用scrapy发送post请求的坑

>>> r = requests.post('http://httpbin.org/post', data = {'key':'value'})

>>> payload = (('key1', 'value1'), ('key1', 'value2'))
>>> r = requests.post('http://httpbin.org/post', data=payload)
>>> print(r.text)
{
  ...
  "form": {
    "key1": [
      "value1",
      "value2"
    ]
  },
  ...
}

>>> import json

>>> url = 'https://api.github.com/some/endpoint'
>>> payload = {'some': 'data'}

>>> r = requests.post(url, data=json.dumps(payload))

>>> url = 'https://api.github.com/some/endpoint'
>>> payload = {'some': 'data'}

>>> r = requests.post(url, json=payload)

return [FormRequest(url="http://www.example.com/post/action",
                    formdata={'name': 'John Doe', 'age': '27'},
                    callback=self.after_post)]

return scrapy.FormRequest(url, formdata=(payload))

return scrapy.Request(url, body=json.dumps(payload), method='POST', headers={'Content-Type': 'application/json'},)

my_data = {'field1': 'value1', 'field2': 'value2'}
request = scrapy.Request( url, method='POST', 
                          body=json.dumps(my_data), 
                          headers={'Content-Type':'application/json'} )

class FormRequest(Request):

    def __init__(self, *args, **kwargs):
        formdata = kwargs.pop('formdata', None)
        if formdata and kwargs.get('method') is None:
            kwargs['method'] = 'POST'

        super(FormRequest, self).__init__(*args, **kwargs)

        if formdata:
            items = formdata.items() if isinstance(formdata, dict) else formdata
            querystr = _urlencode(items, self.encoding)
            if self.method == 'POST':
                self.headers.setdefault(b'Content-Type', b'application/x-www-form-urlencoded')
                self._set_body(querystr)
            else:
                self._set_url(self.url + ('&' if '?' in self.url else '?') + querystr)
            ###


def _urlencode(seq, enc):
    values = [(to_bytes(k, enc), to_bytes(v, enc))
              for k, vs in seq
              for v in (vs if is_listlike(vs) else [vs])]
    return urlencode(values, doseq=1)

class Request(object_ref):

    def __init__(self, url, callback=None, method='GET', headers=None, body=None,
                 cookies=None, meta=None, encoding='utf-8', priority=0,
                 dont_filter=False, errback=None, flags=None):

        self._encoding = encoding  # this one has to be set first
        self.method = str(method).upper()

def request(method, url, **kwargs):
    """Constructs and sends a :class:`Request <Request>`.

    :param method: method for the new :class:`Request` object.
    :param url: URL for the new :class:`Request` object.
    :param params: (optional) Dictionary or bytes to be sent in the query string for the :class:`Request`.
    :param data: (optional) Dictionary or list of tuples ``[(key, value)]`` (will be form-encoded), bytes, or file-like object to send in the body of the :class:`Request`.
    :param json: (optional) json data to send in the body of the :class:`Request`.
    :param headers: (optional) Dictionary of HTTP Headers to send with the :class:`Request`.
    :param cookies: (optional) Dict or CookieJar object to send with the :class:`Request`.
    :param files: (optional) Dictionary of ``'name': file-like-objects`` (or ``{'name': file-tuple}``) for multipart encoding upload.
        ``file-tuple`` can be a 2-tuple ``('filename', fileobj)``, 3-tuple ``('filename', fileobj, 'content_type')``
        or a 4-tuple ``('filename', fileobj, 'content_type', custom_headers)``, where ``'content-type'`` is a string
        defining the content type of the given file and ``custom_headers`` a dict-like object containing additional headers
        to add for the file.
    :param auth: (optional) Auth tuple to enable Basic/Digest/Custom HTTP Auth.
    :param timeout: (optional) How many seconds to wait for the server to send data
        before giving up, as a float, or a :ref:`(connect timeout, read
        timeout) <timeouts>` tuple.
    :type timeout: float or tuple
    :param allow_redirects: (optional) Boolean. Enable/disable GET/OPTIONS/POST/PUT/PATCH/DELETE/HEAD redirection. Defaults to ``True``.
    :type allow_redirects: bool
    :param proxies: (optional) Dictionary mapping protocol to the URL of the proxy.
    :param verify: (optional) Either a boolean, in which case it controls whether we verify
            the server's TLS certificate, or a string, in which case it must be a path
            to a CA bundle to use. Defaults to ``True``.
    :param stream: (optional) if ``False``, the response content will be immediately downloaded.
    :param cert: (optional) if String, path to ssl client cert file (.pem). If Tuple, ('cert', 'key') pair.
    :return: :class:`Response <Response>` object
    :rtype: requests.Response

    Usage::

      >>> import requests
      >>> req = requests.request('GET', 'http://httpbin.org/get')
      <Response [200]>
    """

    # By using the 'with' statement we are sure the session is closed, thus we
    # avoid leaving sockets open which can trigger a ResourceWarning in some
    # cases, and look like a memory leak in others.
    with sessions.Session() as session:
        return session.request(method=method, url=url, **kwargs)