c# How to handle Stackoverflow exception in recursive function

Question

Hi I am making my web scraping tool, and I need to have a recursive function in milliseconds to view offer availability. But I can't handle the stackoverflow exception because i keep calling the viewoffers() function. Please help :)

public void viewoffers(IWebDriver driver, string user, string pass)
    {
            Thread.Sleep(timespan);

            try { int c = driver.WindowHandles.Count; }
            catch { AbortThread(user); }

            driver.Navigate().GoToUrl("https://as.realtrans.com/webtop/orders/offers/offer_order_viewInfo.asp?user=" + user);

            try { int c = driver.WindowHandles.Count; }
            catch { AbortThread(user); }

            if (driver.Url.ToString().Contains("offer_order_viewInfo.asp?user="))
            {

                try { int c = driver.WindowHandles.Count; }
                catch { AbortThread(user); }

                if (driver.PageSource.Contains("id=\"chkOffer\""))
                {
                    driver.FindElement(By.Id("chkOffer")).Click();
                    driver.FindElement(By.ClassName("CellClass")).FindElement(By.TagName("a")).Click();
                    driver.FindElement(By.Name("btnSubmit")).Click();
                }


                this.viewoffers(driver, user, pass);

            }
            else
            {
                this.reopenaccount(driver, user, pass);

            }
    }


    public void AbortThread(string username)
    {
        RunningAccounts ra = runningAccounts.Find(item => item.account.username == username);
        runningAccounts.Remove(ra);
        threadsList.Remove(ra.thread);
        ra.thread.Abort();

    }

And it will just stop if I make close of the running thread in my program.

Matthew Haugen · Accepted Answer · 2014-07-15 06:15:23Z

1

Alas, recursion and the stack. The solution here, unfortunately, is to write your code in such a way that doesn't use recursion. Remember that recursion is never required. As a general rule of computer science, if you can write it with recursion, you can write it with a loop. It's nothing more than a shortcut, albeit a really nice shortcut to have (up until it overflows). But if you do it in a loop, that should handle all your problems and be way lighter on resources.

I obviously haven't tested this, and it's using a while (true) which I generally consider bad practice, but here's an example that should show the theory behind this conversion:

public void viewoffers(IWebDriver driver, string user, string pass)
{
    while (true)
    {
        Thread.Sleep(timespan);

        try { int c = driver.WindowHandles.Count; }
        catch { AbortThread(user); }

        driver.Navigate().GoToUrl("https://as.realtrans.com/webtop/orders/offers/offer_order_viewInfo.asp?user=" + user);

        try { int c = driver.WindowHandles.Count; }
        catch { AbortThread(user); }

        if (driver.Url.ToString().Contains("offer_order_viewInfo.asp?user="))
        {
            try { int c = driver.WindowHandles.Count; }
            catch { AbortThread(user); }

            if (driver.PageSource.Contains("id=\"chkOffer\""))
            {
                driver.FindElement(By.Id("chkOffer")).Click();
                driver.FindElement(By.ClassName("CellClass")).FindElement(By.TagName("a")).Click();
                driver.FindElement(By.Name("btnSubmit")).Click();
            }
        }
        else
        {
            break;
        }
    }

    this.reopenaccount(driver, user, pass);
}

}

edited Jul 15, 2014 at 6:15

answered Jul 15, 2014 at 5:31

Matthew Haugen

13.4k5 gold badges41 silver badges55 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Matthew Haugen Over a year ago

Make sure you read through it, of course. I think it should work, but you should never blindly run code off the internet without reading it and understanding it first. :)

Asaf Over a year ago

@MatthewHaugen Like boost? ;)

Vincent Over a year ago

Uhm, it could be me still needing to wake up. But your suggestion looks like it's still recursive since viewoffers still calls (this.)viewsoffers.

Matthew Haugen Over a year ago

Asaf, something like that. :). @Vincent oh gosh. Maybe I have the opposite problem--I need to go to bed. That's embarrassing. My apologies. I just forgot to delete that line. Fixing it now...

Matthew Haugen Over a year ago

See, everyone, why we don't blindly run code off the internet? :)

Collectives™ on Stack Overflow

c# How to handle Stackoverflow exception in recursive function

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related