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"""
This module implements the FormRequest class which is a more covenient class
(than Request) to generate Requests based on form data.
See documentation in docs/topics/request-response.rst
"""
import urllib
from cStringIO import StringIO
from scrapy.xlib.ClientForm import ParseFile
from scrapy.http.request import Request
from scrapy.utils.python import unicode_to_str
def _unicode_to_str(string, encoding):
if hasattr(string, '__iter__'):
return [unicode_to_str(k, encoding) for k in string]
else:
return unicode_to_str(string, encoding)
class FormRequest(Request):
def __init__(self, *args, **kwargs):
formdata = kwargs.pop('formdata', None)
super(FormRequest, self).__init__(*args, **kwargs)
if formdata:
items = formdata.iteritems() if isinstance(formdata, dict) else formdata
query = [(unicode_to_str(k, self.encoding), _unicode_to_str(v, self.encoding))
for k, v in items]
self.method = 'POST'
self._set_body(urllib.urlencode(query, doseq=1))
self.headers['Content-Type'] = 'application/x-www-form-urlencoded'
@classmethod
def from_response(cls, response, formname=None, formnumber=0, formdata=None,
clickdata=None, dont_click=False, **kwargs):
encoding = getattr(response, 'encoding', 'utf-8')
forms = ParseFile(StringIO(response.body), response.url,
encoding=encoding, backwards_compat=False)
if not forms:
raise ValueError("No <form> element found in %s" % response)
form = None
if formname:
for f in forms:
if f.name == formname:
form = f
break
if not form:
try:
form = forms[formnumber]
except IndexError:
raise IndexError("Form number %d not found in %s" % (formnumber, response))
if formdata:
# remove all existing fields with the same name before, so that
# formdata fields properly can properly override existing ones,
# which is the desired behaviour
form.controls = [c for c in form.controls if c.name not in formdata]
for k, v in formdata.iteritems():
for v2 in v if hasattr(v, '__iter__') else [v]:
form.new_control('text', k, {'value': v2})
if dont_click:
url, body, headers = form._switch_click('request_data')
else:
url, body, headers = form.click_request_data(**(clickdata or {}))
kwargs.setdefault('headers', {}).update(headers)
return cls(url, method=form.method, body=body, **kwargs)
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