Multiple inheritance in scrapy spiders

Question

Is it possible to create a spider which inherits the functionality from two base spiders, namely SitemapSpider and CrawlSpider?

I have been trying to scrape data from various sites and realized that not all sites have listing of every page on the website, thus a need to use CrawlSpider. But CrawlSpider goes through a lot of junk pages and is kind of an overkill.

What I would like to do is something like this:

1. Start my Spider which is a subclass of SitemapSpider and pass regex matched responses to the parse_products to extract useful information method.

2. Go to links matching the regex: /reviews/ from the products page, and sending the data to parse_review function.
   Note: "/reviews/" type pages are not listed in sitemap

3. Extract information from /reviews/ page

4. CrawlSpider is basically for recursive crawls and scraping

-------ADDITIONAL DETAILS-------

The site in question is www.flipkart.com The site has listings for a lot of products, with each page having its own detail page. Along with the details page, their is a corresponding "review" page for the product. The link to the review page is also available on the product details page.

Note: Review pages are not listed on the sitemap.

class WebCrawler(SitemapSpider, CrawlSpider):
    name = "flipkart"
    allowed_domains = ['flipkart.com']
    sitemap_urls = ['http://www.flipkart.com/robots.txt']
    sitemap_rules = [(regex('/(.*?)/p/(.*?)'), 'parse_product')]
    start_urls = ['http://www.flipkart.com/']
    rules = [Rule(LinkExtractor(allow=['/(.*?)/product-reviews/(.*?)']), 'parse_reviews'),
             Rule(LinkExtractor(restrict_xpaths='//div[@class="fk-navigation fk-text-center tmargin10"]'), follow=True)]

    def parse_product(self, response):
        loader = FlipkartItemLoader(response=response)
        loader.add_value('pid', 'value of pid')
        loader.add_xpath('name', 'xpath to name')
        yield loader.load_item()

    def parse_reviews(self, response):
        loader = ReviewItemLoader(response=response)
        loader.add_value('pid','value of pid')
        loader.add_xpath('review_title', 'xpath to review title')
        loader.add_xpath('review_text', 'xpath to review text')
        yield loader.load_item()

Answer 1

You are on the right track, the only thing left is at the end of your parse_product function, you have to yield all the urls extracted by the crawler like so

def parse_product(self, response):
    loader = FlipkartItemLoader(response=response)
    loader.add_value('pid', 'value of pid')
    loader.add_xpath('name', 'xpath to name')
    yield loader.load_item()

    # CrawlSpider defines this method to return all scraped urls.
    yield from self.parse(response)

If you don't have the yield from syntax then just use

for req in self.parse(response):
    yield req