Scrapy, javascript form, not crawling next page - scrapy

Question

I am having an issue. I am using scrapy to extract data from HTML tables that are displayed after a form search. The problem is that it will not continue to crawl to the next page. I have tried multiple combinations of rules. I understand that it is not recommended to override the default parse logic in CrawlSpider. I have found many answers that fix others issues but, I have not been able to find a solution in which a form POST must occur first. I look at my code and see that it requests the allowed_urls then POST to search.do and the results are returned in HTML formatted results page and thus the parsing begins. Here is my code and I have replaced the real url with nourl.com
from scrapy.contrib.spiders import CrawlSpider, Rule
from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
from scrapy.selector import Selector
from scrapy.http import FormRequest, Request
from EMD.items import EmdItem
class EmdSpider(CrawlSpider):
name = "emd"
start_urls = ["https://nourl.com/methor"]
rules = (
Rule(SgmlLinkExtractor(restrict_xpaths=('//div//div//div//span[#class="pagelinks"]/a[#href]'))),
Rule(SgmlLinkExtractor(allow=('')), callback = 'parse_item')
)
def parse_item(self, response):
url = "https://nourl.com/methor-app/search.do"
payload = {"county": "ANDERSON"}
return (FormRequest(url, formdata = payload, callback = self.parse_data))
def parse_data(self, response):
print response
sel = Selector(response)
items = sel.xpath('//td').extract()
print items
I have left allow = ('') blank because I have tried so many combinations of it. Also in my xpath leads to this:
<div align="center">
<div id="bg">
<!--
Main Container
-->
<div id="header2"></div>
<!--
Content
-->
<div id="content">
<!--
Hidden/Accessible Headers
-->
<h1 class="hide"></h1>
<!--
InstanceBeginEditable name="Content"
-->
<h2></h2>
<p align="left"></p>
<p id="printnow" align="center"></p>
<p align="left"></p>
<span class="pagebanner"></span>
<span class="pagelinks">
[First/Prev]
<strong></strong>
,
<a title="Go to page 2" href="/methor-app/results.jsp?d-49653-p=2"></a>
,
<a title="Go to page 3" href="/methor-app/results.jsp?d-49653-p=3"></a>
[
/
]
</span>
I have checked with multiple tools and my xpath is correctly pointing to the URLs to go to next page. my output in the command prompt is only grabbing data from the first page. I have seen a couple of tutorials where the code contains a yield statement but I am not sure what that does other than "tell the function that it will be used again later without loosing its data" Any ideas would be helpful. Thank you!!!

Answer 1

It may be because you need to select the actual URL in your rule, not just the <a>node. [...] in XPath is used to make a condition, not select something. Try:
//span[#class="pagelinks"]/a/#href
Also a few comments:
How did you find this HTML? Beware of tools to find XPath, as HTML retrieved with browsers and with scrapy may be different, because scrapy doesn't handle Javascript (which can be used to generated the page you're looking at, and also some browsers try to sanitize HTML).
It may not be the case here, but the "javascript form" in a scrapy question spooked me. You should always check that the content of response.body is what you expect.
//div//div//div is exactly the same as //div. The two slashes means we don't care anymore about the structure, just select all the nodes named div in the children of the current node. That also why here //span[...] might do the trick.