title: Crawling: Difference between "query string parameter" and "request payload"
body: <p>I am trying to crawl a ajax site using Scrapy, the url is <a href="http://www.target.com/p/bounty-select-a-size-white-paper-towels-12-mega-rolls/-/A-14920157#prodSlot=medium_1_2&amp;term=bounty" rel="noreferrer">http://www.target.com/p/bounty-select-a-size-white-paper-towels-12-mega-rolls/-/A-14920157#prodSlot=medium_1_2&amp;term=bounty</a></p>
  
  <p>My goal is to get the store id. I did that by checking all the XHR request in chrome developer tool and find the one with name ("v1?request_type=availability&amp;key=.....") to be the one I want.</p>
  
  <p>My questions are:</p>
  
  <ol>
  <li><p>In developer tool, there is "Query string parameter" which seems to be the part after <code>?</code> of the request url.   There is also Request Payload section, which is a json.
  So which one should I use to send to the server? If i need request payload, how can I send a json file?</p></li>
  <li><p>when i send the whole url to get json:
  <a href="https://api.target.com/available_to_promise_aggregator/v1?request_type=availability&amp;key=q0jGNkIyuqUTYIlzZKoCfK6ugaNGSP8h" rel="noreferrer">https://api.target.com/available_to_promise_aggregator/v1?request_type=availability&amp;key=q0jGNkIyuqUTYIlzZKoCfK6ugaNGSP8h</a></p></li>
  </ol>
  
  <p>I get "Request method 'GET' not supported", so should I use POST instead or there is something wrong I did? </p>