title: How to process while scrapy crawling data from an url which one's data controlled by another url
body: <p>Recently I'm researching crawling,and I choose <code>dataurl</code>,I can easily get the data with scrapy.But it is always responsing English data.</p>
  
  <p>For getting Chinese data,I found  what <code>dataurl</code> responses depends on what   country language of  <code>urlControllLangContentByServerSide</code> is with parameter  <code>&amp;plang=1</code>. I even append <code>&amp;plang=3</code>  or formdata <code>{plang:3}</code>for <code>dataurl</code>,but that doesn't work </p>
  
  <p>In short,<code>urlControllLangContentByServerSide</code> should be visited first ,if i want to get the Chinese data of <code>dataurl</code>,this has been proved by  many tests on postman,and I don't know how to deal with this  in code.</p>
  
  <p>Thank you for your time for reading and thinking.</p>
  
  <pre><code> def start_requests(self):
       urlControllLangContentByServerSide='http://messefrankfurt.kenti-creative.com/index.php?moduleId=129&amp;pageName=list2&amp;pId=14&amp;plang=3'
       dataurl='http://messefrankfurt.kenti-creative.com/modules/exhibitor/ajax/more2.php?moduleId=129&amp;pageName=list2&amp;pId=14&amp;yId=0&amp;hId=0&amp;uId=-2&amp;cId=undefined&amp;aId=-1&amp;fId=0&amp;plang=3'
      # I even append &amp;plang=3 for dataurl,But that doesn't work 
       for  s in range(5):
           time.sleep(.5)  #im trying to visit this url many times to tell server what  
           #language should be used!  maybe that server uses session to controll language data.
           yield scrapy.Request(urlControllLangContentByServerSide,callback=self.parse_m,method='POST')
  
       for  i in range(5):
           form_data={"page":"%s" % i}
           self.current_index=i
           yield scrapy.FormRequest(url, callback=self.parse,
                               method='POST', formdata=form_data)
       print(self.wrongs)
   def  parse_m(self,response):
       with open('mother%s.html'% random.randint(3,90) ,'wb') as f:
           f.write(response.body)
  </code></pre>