Spider/Robot UserAgent Detection C#

Question

I'm working on an application that redirects users to upgrade browser if they are not on our browser list.

My goal is to create an exception to detect if they are a crawler, based on their UserAgent string.

At this point, I'm getting the a message ..."no definition or extension method for .ToLower"

Here is my code:

    private bool IsValidCrawler(HttpRequestBase request)
    {
        bool isCrawler = true;

        switch (request.Browser.Crawler.ToLower())  
        {
            case "googlebot":
            case "bingbot":
            case "yahoo!":
            case "facebookexternalhit":
            case "facebookplatform":
                break;
        }

        return isCrawler;
    }

Can anyone point me to where I have gone wrong?

Answer 1

If you look at the documentation for the Crawler property (http://msdn.microsoft.com/en-us/library/system.web.configuration.httpcapabilitiesbase.crawler(v=vs.110).aspx) you'll notice it's a boolean type.

The property itself will let you know if the request is coming from a known crawler. You can try the following for the time being. Leaving the method so you don't have to change too much.

private bool IsValidCrawler(HttpRequestBase request)
{
    bool isCrawler = request.Browser.Crawler;

    return isCrawler;
}