Ruby

A Simple Web Crawler

See more Spider Examples

This demonstrates a very simple web crawler using the Chilkat Spider component. Ruby

require 'chilkat'

success = false

spider = Chilkat::CkSpider.new()

seenDomains = Chilkat::CkStringArray.new()
seedUrls = Chilkat::CkStringArray.new()

seenDomains.put_Unique(true)
seedUrls.put_Unique(true)

# You will need to change the start URL to something else...
seedUrls.Append("http://something.whateverYouWant.com/")

# Set outbound URL exclude patterns
# URLs matching any of these patterns will not be added to the 
# collection of outbound links.
spider.AddAvoidOutboundLinkPattern("*?id=*")
spider.AddAvoidOutboundLinkPattern("*.mypages.*")
spider.AddAvoidOutboundLinkPattern("*.personal.*")
spider.AddAvoidOutboundLinkPattern("*.comcast.*")
spider.AddAvoidOutboundLinkPattern("*.aol.*")
spider.AddAvoidOutboundLinkPattern("*~*")

# Use a cache so we don't have to re-fetch URLs previously fetched.
spider.put_CacheDir("c:/spiderCache/")
spider.put_FetchFromCache(true)
spider.put_UpdateCache(true)

while seedUrls.get_Count() > 0

    url = seedUrls.pop()
    spider.Initialize(url)

    # Spider 5 URLs of this domain.
    # but first, save the base domain in seenDomains
    domain = spider.getUrlDomain(url)
    seenDomains.Append(spider.getBaseDomain(domain))

    for i in 0 .. 4
        success = spider.CrawlNext()
        if (success == true)

            # Display the URL we just crawled.
            print spider.lastUrl() + "\n";

            # If the last URL was retrieved from cache,
            # we won't wait.  Otherwise we'll wait 1 second
            # before fetching the next URL.
            if (spider.get_LastFromCache() != true)
                spider.SleepMs(1000)
            end

        else
            # cause the loop to exit..
            i = 999
        end

    end

    # Add the outbound links to seedUrls, except
    # for the domains we've already seen.
    for i in 0 .. spider.get_NumOutboundLinks() - 1

        url = spider.getOutboundLink(i)
        domain = spider.getUrlDomain(url)
        baseDomain = spider.getBaseDomain(domain)
        if (seenDomains.Contains(baseDomain) == false)
            # Don't let our list of seedUrls grow too large.
            if (seedUrls.get_Count() < 1000)
                seedUrls.Append(url)
            end

        end

    end

end