Question

When users are entering information on my site and experience an exception, what is the best way to capture that exception. I would like to know what were they filling out on the form when the exception occurred. How have you handled it? what tool have you used? I have looked into ELMAH and log4net and currently trying to use log4net to capture this information. Any suggestions on what is the best way to capture form fields?

Answer 1

In your Application_Error in Global.asax.cs, you can access the following and log them. This is what we do (with our specifics removed).

Obviously in place of each var whatever = ..., you would do LogInSomeWay(whatever). This code just demonstrates assigning each important piece of the current experience to a variable.

Hope this helps.

Code

void Application_Error(object sender, EventArgs e)
{
    Exception ex = Server.GetLastError();
    HttpContext context = HttpContext.Current;

    bool requestAvailable = false;
    try
    {
        if (context.Request != null)
        {
            requestAvailable = true;
        }
    }
    catch{}

    if (context != null) var serverName = context.Server.MachineName;

    if (context != null && requestAvailable)
    {
        var referrer = context.Request.UrlReferrer != null ? context.Request.UrlReferrer.ToString() : "";

        // If you use forms authentication and define your own principal, do some logging with it here
        OurPrincipal user = OurContext.Current.LoggedOnPrincipal;
        if (user != null && user.Identity != null && user.Identity.IsAuthenticated && user.Person != null)
        {
            var logonName = user.Person.LogonName;
            var loginPersonName = user.Person.FirstName + " " + user.Person.LastName;
        }

        var userIP = context.Request.UserHostAddress;
        var userDns = context.Request.UserHostName;
        var userAgent = context.Request.UserAgent;
        var exceptionText = ex.ToString();

        foreach (string key in context.Request.ServerVariables.AllKeys)
        {
            var currentServerVarKey = key;
            var currentServerVarValue = context.Request.ServerVariables[key];
        }

        if (context.Request.ServerVariables["REQUEST_METHOD"] == "POST"
            && context.Request.Form != null && context.Request.Form.AllKeys != null)
        {
            foreach (string key in context.Request.Form.AllKeys)
            {
                var currentFormKey = key;
                var currentFormValue = context.Request.Form[key];
            }
        }
    }
}