向scray中的ASMX Webservice发送Ajax请求

Question

我正在尝试浏览网站ASP.NET Webform。查看源页面可以发现，每当页面加载时，表单都会从服务器接收一个VarsSessionID。当单击继续按钮时，表单向ASMX Webserivce发送一个AJAX请求。重定向到显示新搜索结果的url。在

我已经实现了my scrapy spider来提交ajax post请求，如图所示：

import scrapy
from scrapy.http import *
from scrapy.selector import Selector
import json
from scrapy.utils.response import open_in_browser



class TestSpider(scrapy.Spider):
    name = "test"
    allowed_domains = ['customer2.videcom.com']
    start_urls = ['http://customer2.videcom.com/med-
    view/VARS/Public/CustomerPanels/requirements.aspx?country=ng&lang=en']

def parse(self, response):
    form_data = {
        'VarsSessionID': '',
        '__VIEWSTATE': '/wEPDwULLTE4MTk4NDM5NjEPZBYCAgMPZBYCAgMPFgIeB1Zpc2libGVoZGSNuC4VK36MoPTmce49gcH1j2nxAPDYsLXii0G/syddwQ=='}
    yield FormRequest.from_response(response,
                                    formid='frmChangePage',
                                    formdata=form_data,
                                    method='POST',
                                    callback=self.after_parse,
                                    url='http://customer2.videcom.com/med-view/VARS/Public/CustomerPanels/requirements.aspx?country=ng&lang=en',
                                    )

def after_parse(self, response):
    print "====RESPONSE==="
    print response.headers
    print "=========="
    print response.request.headers
    print "=========="
    VarsSessionID = Selector(response=response).xpath("//*[@id='VarsSessionID']/@value").extract()[0]
    viewstate = Selector(response=response).xpath("//*[@id='__VIEWSTATE']/@value").extract()[0]
    print "VarsSessionID: " + VarsSessionID
    print "__VIEWSTATE: " + viewstate
    url = "http://customer2.videcom.com/med-view/VARS/Public/WebServices/AvailabilityWS.asmx/GetFlightAvailability?VarsSessionID="+VarsSessionID
    payload = {
        "FormData":
            {
                'Origin': ['LOS'],
                'VarsSessionID': VarsSessionID,
                'Destination': ['ABV'],
                'DepartureDate': ['05-May-2017'],
                'ReturnDate': '',
                'Adults': '1',
                'Children': '0',
                'SmallChildren': '0',
                "Seniors": '0',
                "Students": '0',
                "Infants": '0',
                "Youths": '0',
                "Teachers": '0',
                "SeatedInfants": '0',
                "EVoucher": '',
                "recaptcha": 'SHOW',
                "SearchUser": 'PUBLIC',
                "SearchSource": "requirements"
            }, "IsMMBChangeFlightMode": 'false'
    }
    headers = {
        'Accept': 'application/json, text/javascript, */*',
        'Accept-Encoding': 'gzip, deflate, br',
        'accept-language': 'en_US',
        'Connection': 'keep-alive',
        'content-type': 'application/json',
        'Cookie': {'VarsSessionID':''},
        'User-Agent': "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36"
    }
    yield Request(url,
                  callback=self.after_search,
                  method='POST',
                  body=json.dumps(payload),
                  headers=headers)

def after_search(self, response):
    print "========SEARCH HEADERS========"
    print response.headers
    print response.request.headers
    open_in_browser(response)

我使用Chrome开发工具检查了头文件（请求和响应），以确定cookies和其他头信息。在

在运行上面的代码时，我一直得到一个Internal Server Error 500，如下所示：

^{pr2}$

我需要帮助来计算如何发布数据和接收搜索结果，例如当我用浏览器搜索时。谢谢

Answer 1

将请求中硬编码的__VIEWSTATE参数替换为“fresh”参数。在

获取某个时间后的复杂状态是无效的。在

有时在ASP网站上，FormRequest.from_response无法正确捕获此参数，因此您可能需要检查响应.正文以了解如何提取__VIEWSTATE。在

下面是一个很好的例子：https://blog.scrapinghub.com/2016/04/20/scrapy-tips-from-the-pros-april-2016-edition/