我正在使用scrapy向网站发出表单请求。表单需要上传pdf文件，我们如何在Scrapy中完成。我试着这样 -
<groupId>org.alfresco</groupId>
<artifactId>alfresco-repository</artifactId>
<version>5.1</version>
<classifier>tests</classifier>
<scope>test</scope>
答案 0 :(得分：1)
目前，Scrapy没有内置支持上传文件。
在RFC1867中指定了通过HTTP中的表单上传文件。根据规范，需要Content-Type: multipart/form-data的HTTP请求（在您的代码中为application/x-www-form-urlencoded）。
要使用Scrapy实现文件上传，您需要：
scrapy.Request开始（而不是FormRequest）。Content-Type标头值。答案 1 :(得分：1)
我花了整整一天的时间试图弄清楚如何实现这一点。 最终，我遇到了2016年以来从未合并过的Scrapy pull request，其中包含一个多部分表单请求的实现：
from scrapy import FormRequest
from six.moves.urllib.parse import urljoin, urlencode
import lxml.html
from parsel.selector import create_root_node
import six
import string
import random
from scrapy.http.request import Request
from scrapy.utils.python import to_bytes, is_listlike
from scrapy.utils.response import get_base_url
class MultipartFormRequest(FormRequest):
def __init__(self, *args, **kwargs):
formdata = kwargs.pop('formdata', None)
kwargs.setdefault('method', 'POST')
super(MultipartFormRequest, self).__init__(*args, **kwargs)
content_type = self.headers.setdefault(b'Content-Type', [b'multipart/form-data'])[0]
method = kwargs.get('method').upper()
if formdata and method == 'POST' and content_type == b'multipart/form-data':
items = formdata.items() if isinstance(formdata, dict) else formdata
self._boundary = ''
# encode the data using multipart spec
self._boundary = to_bytes(''.join(
random.choice(string.digits + string.ascii_letters) for i in range(20)), self.encoding)
self.headers[b'Content-Type'] = b'multipart/form-data; boundary=' + self._boundary
request_data = _multpart_encode(items, self._boundary, self.encoding)
self._set_body(request_data)
class MultipartFile(object):
def __init__(self, name, content, mimetype='application/octet-stream'):
self.name = name
self.content = content
self.mimetype = mimetype
def _get_form_url(form, url):
if url is None:
return urljoin(form.base_url, form.action)
return urljoin(form.base_url, url)
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)
def _multpart_encode(items, boundary, enc):
body = []
for name, value in items:
body.append(b'--' + boundary)
if isinstance(value, MultipartFile):
file_name = value.name
content = value.content
content_type = value.mimetype
body.append(
b'Content-Disposition: form-data; name="' + to_bytes(name, enc) + b'"; filename="' + to_bytes(file_name,
enc) + b'"')
body.append(b'Content-Type: ' + to_bytes(content_type, enc))
body.append(b'')
body.append(to_bytes(content, enc))
else:
body.append(b'Content-Disposition: form-data; name="' + to_bytes(name, enc) + b'"')
body.append(b'')
body.append(to_bytes(value, enc))
body.append(b'--' + boundary + b'--')
return b'\r\n'.join(body)
def _get_form(response, formname, formid, formnumber, formxpath):
"""Find the form element """
root = create_root_node(response.text, lxml.html.HTMLParser,
base_url=get_base_url(response))
forms = root.xpath('//form')
if not forms:
raise ValueError("No <form> element found in %s" % response)
if formname is not None:
f = root.xpath('//form[@name="%s"]' % formname)
if f:
return f[0]
if formid is not None:
f = root.xpath('//form[@id="%s"]' % formid)
if f:
return f[0]
# Get form element from xpath, if not found, go up
if formxpath is not None:
nodes = root.xpath(formxpath)
if nodes:
el = nodes[0]
while True:
if el.tag == 'form':
return el
el = el.getparent()
if el is None:
break
encoded = formxpath if six.PY3 else formxpath.encode('unicode_escape')
raise ValueError('No <form> element found with %s' % encoded)
# If we get here, it means that either formname was None
# or invalid
if formnumber is not None:
try:
form = forms[formnumber]
except IndexError:
raise IndexError("Form number %d not found in %s" %
(formnumber, response))
else:
return form
def _get_inputs(form, formdata, dont_click, clickdata, response):
try:
formdata = dict(formdata or ())
except (ValueError, TypeError):
raise ValueError('formdata should be a dict or iterable of tuples')
inputs = form.xpath('descendant::textarea'
'|descendant::select'
'|descendant::input[not(@type) or @type['
' not(re:test(., "^(?:submit|image|reset)$", "i"))'
' and (../@checked or'
' not(re:test(., "^(?:checkbox|radio)$", "i")))]]',
namespaces={
"re": "http://exslt.org/regular-expressions"})
values = [(k, u'' if v is None else v)
for k, v in (_value(e) for e in inputs)
if k and k not in formdata]
if not dont_click:
clickable = _get_clickable(clickdata, form)
if clickable and clickable[0] not in formdata and not clickable[0] is None:
values.append(clickable)
values.extend(formdata.items())
return values
def _value(ele):
n = ele.name
v = ele.value
if ele.tag == 'select':
return _select_value(ele, n, v)
return n, v
def _select_value(ele, n, v):
multiple = ele.multiple
if v is None and not multiple:
# Match browser behaviour on simple select tag without options selected
# And for select tags wihout options
o = ele.value_options
return (n, o[0]) if o else (None, None)
elif v is not None and multiple:
# This is a workround to bug in lxml fixed 2.3.1
# fix https://github.com/lxml/lxml/commit/57f49eed82068a20da3db8f1b18ae00c1bab8b12#L1L1139
selected_options = ele.xpath('.//option[@selected]')
v = [(o.get('value') or o.text or u'').strip() for o in selected_options]
return n, v
def _get_clickable(clickdata, form):
"""
Returns the clickable element specified in clickdata,
if the latter is given. If not, it returns the first
clickable element found
"""
clickables = [
el for el in form.xpath(
'descendant::*[(self::input or self::button)'
' and re:test(@type, "^submit$", "i")]'
'|descendant::button[not(@type)]',
namespaces={"re": "http://exslt.org/regular-expressions"})
]
if not clickables:
return
# If we don't have clickdata, we just use the first clickable element
if clickdata is None:
el = clickables[0]
return (el.get('name'), el.get('value') or '')
# If clickdata is given, we compare it to the clickable elements to find a
# match. We first look to see if the number is specified in clickdata,
# because that uniquely identifies the element
nr = clickdata.get('nr', None)
if nr is not None:
try:
el = list(form.inputs)[nr]
except IndexError:
pass
else:
return (el.get('name'), el.get('value') or '')
# We didn't find it, so now we build an XPath expression out of the other
# arguments, because they can be used as such
xpath = u'.//*' + \
u''.join(u'[@%s="%s"]' % c for c in six.iteritems(clickdata))
el = form.xpath(xpath)
if len(el) == 1:
return (el[0].get('name'), el[0].get('value') or '')
elif len(el) > 1:
raise ValueError("Multiple elements found (%r) matching the criteria "
"in clickdata: %r" % (el, clickdata))
else:
raise ValueError('No clickable element matching clickdata: %r' % (clickdata,))
这是我用来调用请求的代码（在我的情况下，我需要上传图片）：
with open(img_path, 'rb') as file:
img = file.read()
file_name = os.path.basename(img_path)
multipart_file = MultipartFile(file_name, img, "image/png")
form_data = {
"param": "value", # this is an example of a text parameter
"PicUpload": multipart_file
}
yield MultipartFormRequest(url=upload_url, formdata=form_data,
callback=self.my_callback)
可惜的是已经过去了这么长时间，而Scrapy仍然没有内置的方法来执行此操作，特别是因为几年前有人编写了一个非常简单的实现。