Rahul Soni's blog

ASP.NET:How to write error messages into a text file using a simple httpModule

In one of my previous posts, I mentioned about how to troubleshoot some issues with the use of a module. In this post, I will show you how a similar module could be of use when you want to log all the errors in a text file for troubleshooting purposes. Please ensure that C:\Temp folder has Write access for the account that is running the IIS Worker Process. Here is the code for the module...

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.IO;
namespace myModules
{
    class Trigger:IHttpModule
    {
        public void Init(System.Web.HttpApplication context)
        {
            context.EndRequest += new EventHandler(this.EndRoutine);
        }
        public void EndRoutine(object o, EventArgs e)
        {
            HttpApplication myApp;
            myApp = (HttpApplication)o;
            HttpContext c = myApp.Context;
            if (myApp.Context.AllErrors != null)
            {
                StreamWriter sw = new StreamWriter("C:\\Temp\\ErrorList.txt", true);
                foreach (Exception ex in myApp.Context.AllErrors)
                {
                    sw.WriteLine("Error occurred at #{0}", DateTime.Now.ToString());
                    sw.WriteLine("Error occurred in page #{0}", c.Request.FilePath);
                    sw.WriteLine(ex.InnerException.Message);
                    sw.WriteLine(ex.InnerException.StackTrace);
                    sw.WriteLine();
                }
                sw.Dispose();
            }
        }
        public void Dispose()
        {
            //Nothing to Dispose as of now
        }
    }
}

You can save the downloaded file to the bin folder of your web application and add the following to the web.config...

        <httpModules>
            <add name="Trigger" type="myModules.Trigger, myModules"/>
        </httpModules>

Here is the sample output (C:\Temp\ErrorList.txt) for one of the applications where I have used the Throw New AppDomainUnloadedException or similar lines to create the error...

Hope this helps,
Rahul

Quote of the day:
The nice thing about standards is that there are so many of them to choose from. - Andrew S. Tanenbaum

Posted at > 6:10 PM IST

Logparser Scenario 9:Find out what is the peak time for your IIS Server

This blog entry is a continuation of the KB Article http://support.microsoft.com/?id=910447

Scenario 9:Find out what is the peak time for your IIS Server

How can you find out what is the peak time (peak hour) for your Website using Logparser?

Answer:

Logparser "SELECT quantize(time,60), count(*) as Frequency from ex080716.log GROUP BY quantize(time,60) order by quantize(time, 60)" -rtp:-1

Here is a brief snapshot of my LogFile...

And here is the output...

QUANTIZE(time, 60) Frequency
------------------ ---------
02:37:00           4
02:38:00           3
02:39:00           8
02:40:00           55
02:41:00           215
02:45:00           40
02:46:00           36

Statistics:
-----------
Elements processed: 361
Elements output:    7
Execution time:     0.00 seconds

You may also try...

Logparser "SELECT quantize(time,60), count(*) as Frequency INTO Image.GIF from ex.log GROUP BY quantize(time,60) order by quantize(time, 60)"

Here is the output...

This tells me that 2:41 GMT is the Peak Minute for my web-site. If you want to get the details per hour... change the query to...

Logparser "SELECT quantize(time,3600), count(*) as Frequency INTO Image.GIF from ex.log GROUP BY quantize(time,3600) order by quantize(time, 3600)"

As you can easily figure out, my site doesn't have too many hits after all

Hope this helps...
Rahul

Quote of the day:
People who have no weaknesses are terrible; there is no way of taking advantage of them. - Anatole France

Posted at > 10:07 AM IST

Run a batch file as a specific User (or Administrator) from ASP.NET...

...well first of all, I am NOT recommending it, but sometimes it could be necessary! Now, let's proceed to the code...

1. Create a page called RunBatchFile.vb and paste the following...

Imports System.Diagnostics
Imports System.IO
Partial Class RunBatchFile
    Inherits System.Web.UI.Page
    Dim _password As New System.Security.SecureString
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim password As String
        'Read from any Registry or Encrypted config file if you like for added security.
        password = "YOUR___PASSWORD"  
        For Each c As Char In password
            _password.AppendChar(c)
        Next
        Dim strFilePath As String = "c:\\temp\\test.bat"
        Dim psiMyProcess As ProcessStartInfo = New ProcessStartInfo("cmd.exe")
        psiMyProcess.LoadUserProfile = True
        psiMyProcess.UserName = "Administrator"
        psiMyProcess.Password = _password
        psiMyProcess.UseShellExecute = False
        psiMyProcess.CreateNoWindow = True
        psiMyProcess.RedirectStandardOutput = True
        psiMyProcess.RedirectStandardInput = True
        psiMyProcess.RedirectStandardError = True
        psiMyProcess.WorkingDirectory = "c:\\temp\\"
        Dim prcProcess As Process = Process.Start(psiMyProcess)
        Dim strm As StreamReader = File.OpenText(strFilePath)
        Dim strOut As StreamReader = prcProcess.StandardOutput
        Dim strIn As StreamWriter = prcProcess.StandardInput
        Do While strm.Peek() <> -1
            strIn.WriteLine(strm.ReadLine())
        Loop
        strm.Close()
        strIn.WriteLine(String.Format("# {0} ran successfully. Exiting now!", strFilePath))
        strIn.WriteLine("Exit")
        prcProcess.Close()
        Dim strOutput As String = strOut.ReadToEnd().Trim()
        strIn.Close()
        strOut.Close()
        Response.Write(String.Format("<font face=courier size=0>{0}</font>", _
                strOutput.Replace(System.Environment.NewLine, "<br>")))
    End Sub
End Class

2. The batch file that I have is a one liner (and a no-brainer)... [Here, one and two are folders containing a few files]

xcopy one\*.* two /y

3. If everything is in place, you should get something like this as output...

Hope this helps,
Rahul

How to use httpModules to troubleshoot your ASP.NET application

No matter how many things you keep in mind before developing an application, when once they are put in production... quite often you will see something not behaving the way you expected. Many-a-times, the applications would throw an error which you can troubleshoot depending on the error message you found. In this post, my intention is not to cover those "error" scenarios. I intend to cover something which is more problematic to troubleshoot... like intermittent slowness in some pages, or some errors that are coming up and you are not able to locate what's wrong with those bad-pages.

What would you do in those situations??

I know there is not a single correct answer to this question and it is scenario specific. Let me show you one little trick which might help you while troubleshooting your web-applications. This application (module) is no-where near completion... it just shows you how you can use Modules to troubleshoot the issue. You can tweak the code based on your scenario and work accordingly. I will share the plain httpmodule in this post. Once I am done with this module with lots of other automated configuration stuff (like capturing all viewstate, session information, etc), I will update my blog accordingly.

Let's proceed by creating a class Library (I will call it myModules)

1. Add a reference to System.Web
2. Copy the following in a new class file called Trigger.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
namespace myModules
{
    class Trigger:IHttpModule
    {
        DateTime fTimerValue;
        public void Init(System.Web.HttpApplication context)
        {
            context.BeginRequest += new EventHandler(this.BeginRoutine);
            context.EndRequest += new EventHandler(this.EndRoutine);
        }
        public void BeginRoutine(object o, EventArgs e)
        {
            fTimerValue = DateTime.Now;
        }
        public void EndRoutine(object o, EventArgs e)
        {
            HttpApplication myApp;
            TimeSpan t = TimeSpan.MinValue;
            myApp = (HttpApplication)o;
            HttpContext c = myApp.Context;
            if(c.Response.StatusCode == 200)
            {
                t = DateTime.Now - fTimerValue;
                if (t.TotalSeconds > 5)
                {
                    c.Response.Write("Tweak this page!! It took... " + t.TotalSeconds + " seconds");
                    c.Response.Write("<BR>");
                    c.Response.Write("Name > " + c.Request.PhysicalPath);
                    return;
                }
            }
            myApp.Context.Response.Write("This response took " + t.ToString() + " seconds");
        }
        public void Dispose()
        {
            //Nothing to Dispose as of now
        }
    }
}

        <httpModules>
            <add name="Trigger" type="myModules.Trigger, myModules"/>
        </httpModules>

5. I tried this with an Empty project. And introduced Sleep statement in the Page_Load...

    protected void Page_Load(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(26000);
    }

The output is...

 
As I said earlier... this is a very meager output, and not enough to fix the issue. But now that you know how to use Modules to troubleshoot your application, feel free to tweak around the code and fix the issue at hand.

Happy troubleshooting!
Rahul

Visual Studio 2008 - More control over Recent Projects list in Start Page

If you work with a lot of samples, the chances are quite likely that you will end up in a rather dirty list of Recent Projects List in Visual Studio. I'm personally quite nit-picky and I really hate it when I find something like this...

Now... I don't know which of these Samples should I click on (since I have two in the list!). Anyway, there are multiple reasons why you would like to remove the junk entries from this list. One way is to open the Registry and navigate to HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\ProjectMRUList. This list contains all the values you are looking for. Delete the values which you don't like and restart Visual Studio.

Another way, which I think is a smarter one is to download this ZIP and do the following...

1. Extract it anywhere in your machine.
2. Open Visual Studio, click on Tools -> External Tools...
3. Click on Add button and in the Title field, write "Clear Recently Used List"
4. In the Command Line, browse to the <SAVED__PATH>\ClearRecentItems.exe and click on OK.


4. Now, you should have this tool listed on your Tools Menu in VS 2008.

5. Here is the sample output...

Feel free to download the code for this small utility...

Hope this helps,
Rahul

Why do I like overflow:scroll so much?

There are times when you want to incorporate a picture, a large piece of code in a limited web space... ex. a blog post which has a lot of <DIV> tags. Now, to crop or resize the picture may not be the option always. I still see a lot posts where the images are either cropped or line breaks are introduced into the code.

The problem with the line break is that it increases the overhead and time spent on the blogger's part in formatting the post. Apart from that, it also creates chances of typos which would make that code snippet not compile when an end user tries it.

Let's say I have a piece of code which I want to blog about (in Windows Live Writer)...

I use Paste from Visual Studio plugin and really love it. When I paste my code from Visual Studio using the Plugin, here is what I get...

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Reflection" %>
<%@ Import Namespace="System.Drawing" %>
<!DOCTYPE html 'I am making this line even longer' PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@ OutputCache Duration="72000" VaryByParam="none"  Location="Any" %>

See how the 4th line overflows! Not good, right? So, what next???

Noooo... please don't split that line.....

Select View -> HTML Code and add the DIV tag as follows around the code.

<div style="overflow: scroll">

Your Code Or Image.

</div>

Here is the output...

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Reflection" %>
<%@ Import Namespace="System.Drawing" %>
<!DOCTYPE html 'I am making this line even longer' PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@ OutputCache Duration="72000" VaryByParam="none"  Location="Any" %>

Hope this helps,
Rahul

UPDATE> Going forward I will be posting on www.dotnetscraps.com. It will give me much more flexibility in hosting the code and do some of the other things that I have in my mind for quite some time now.

AJAXControl Toolkit issue in VS 2008

When I tried opening the AjaxControlToolkit.sln by double clicking on it, it was throwing the following error at me...

---------------------------
Microsoft Visual Studio
---------------------------
The application for project 'H:\Downloads\AjaxControlToolkit\SampleWebSite' is not installed.

Make sure the application for the project type () is installed.
---------------------------
OK   Help  
---------------------------

To get rid of it, open the SLN file directly from File -> Open -> Project/Solution. Create a backup if you like (when prompted!).

You may also get the following error while trying to compile the Solution...

Parser Error Message: Could not load file or assembly 'System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

This is because, you probably didn't install the AJAXControl Toolkit. Get it from here.

Another error that you could encounter is...

error : Could not load file or assembly 'vjslib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
Done building project "TemplateVSI.csproj" -- FAILED.

Install JS Redist from here and you should be good.

Cheers,
Rahul

UPDATE> Windows Live Writer plug-ins

I have found that a couple of my plug-ins, namely Social Bookmarking and Smiley Plugin  don’t work as expected in Windows Live Writer’s latest version. If you are encountering any issues and running Vista machine, please try running WLW as an Administrator.

Apparently a few things changed with WLW and I am still investigating if there is a way to make this work in a Non-Admin mode. I will keep you posted if I discover the root cause.

Thanks,
Rahul

We now have a team blog...

...and I am pretty excited about it! In our team, we deal with a lot of issues with IIS and ASP.NET and have a plenty of folks in our team who blog individually, and do it pretty well.

We will continue to have our own blogs, but going forward you will see a lot of good information about troubleshooting IIS 7 and ASP.NET from a bunch of really talented folks. Feel free to subscribe to our new team blog  and let me know if you would like to see some more topics that you require help on. It could be anything from simple to complex, related to IIS 7 or ASP.NET. Our focus is not only knowledge sharing, but also sharing some of the troubleshooting skills that we acquire because of handling multiple complex issues as a part of our job.

Definitely, I won't have all the answers, but I am priviledged to be working with quite a lot of smart folks who do !!

As an insider let me tell you that we are coming up with a lot of posts which will help you create different modules with IIS 7. Give us a lot of hits on the new blog </shameless promotion of our team ends!>)

Cheers,
Rahul

Logparser Scenario 8:Checking the traffic/requests between a specific client and server

This blog entry is a continuation of the KB Article http://support.microsoft.com/?id=910447.

Scenario 8: Checking the traffic/requests between a specific client and server

Why would you do it in the first place?
You may want to troubleshoot an authenticate issue for that specific client for the error that s/he reported to you. May be that's why!

Answer:

Logparser "select date, time, c-ip, cs-username, s-sitename, s-computername, s-ip, s-port, cs-method, cs-uri-stem, cs-uri-query, sc-status, sc-substatus,sc-win32-status, sc-bytes, cs-bytes, time-taken,cs-version, cs-host, cs(User-Agent), cs(Cookie), cs(Referer), s-event, s-process-type, s-user-time, s-kernel-time, s-page-faults, s-total-procs, s-active-procs, s-stopped-procs from <FILENAME> where c-ip='Client-IP'" -i:IISW3C -rtp:-1

And the output will be something like...

Hope that helps,
Rahul

The case of changing Time Zones in my Windows Mobile

I joined the Windows Mobile bandwagon pretty late and still getting used to it. No doubt, it is awesome, but it does come with its own set of frills. I realized it when my time zone (Start->Settings->System, Clock & Alarms) always went back to GMT+1 Prague, Budapest. I used to change it often and reset my time, but pretty soon it started frustrating me and I was thinking to go back to the service center to get this fixed.

Thankfully, the troubleshooter in me woke up and I decided to check if this is an issue just with my device or the OS. Pretty soon, I came to know from one of my colleagues, that not only he suffered from the same problem... he also found a fix for it.

Start -> Settings -> Personal Tab

Phone -> Time Zone -> Automatic Change time zone and clock. Uncheck this checkbox and the problem should go away.

Now, a bit of rant...

Windows Mobile is great, but as a newbie, I just don't get this behavior. Why the heck would this be a feature (or is this a bug)?? Changing the time zone sounds fine if I am travelling, but how does it make sense if I am located at Bangalore, have already set my time zone, and next morning I appear in Prague, without a ticket !!! Well, technology can sure take us places, I guess .

<Rant ends!>

Until next time
Rahul

Why am I unable to search for the folder which I know is present (in Vista)?

Or... what exactly is this "Compatibility Files" folder icon doing in my Windows Explorer??

Jerry's Blog explains this stuff beautifully!

So, why am I blogging about this?

Well... to cut the long story short, I have lost almost 3 hours yesterday searching for some files/folders to fix an issue with one of my software which had a corrupted cache folder. The support professionals asked me to delete some specific folder along with a couple of files, and I was not able to find them... no matter how much I searched. In the end, when I clicked on Compatibility Files, I found that the address bar changed as follows... and the files were right there! Honestly, it felt as if those files were giving that mocking smile at me !!

Thought you should know...

Until next time
Rahul

MSIL Trivia - 4 (Spot the difference)

I have created a very simple C# console application which gives me the following MSIL code when compiled... The next screenshot has almost the same code but with some special difference. Can you tell me what could have caused it and is it good or bad?

I will answer this in the comments (or next post as necessary) .

Until then...  

Cheers,
Rahul

A sample to help in other samples related DataSource

There are quite a few times, when I get an issue related with a specific DataControl and I want to bind it to a datasource. All geared up and with full enthusiasm, I start dealing with the issue... and DARN... I find that I did something awfully bad with my SQL Server during my last case!! So now, instead of fixing my core issue, I end up fixing my SQL Server. Since we don't really like digressing from the main issue I am posting this entry on my blog so that I could keep it handy and instead of fixing the SQL server, I can concentrate on fixing the root cause of the issue. By the way, SQL server rocks... more often than not, it is my bad that I end up doing something silly against it

SamplePage1.aspx in C#

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
    public class SampleDataSource
    {
        DataTable dt;
        public SampleDataSource()
        {
            dt = new DataTable();
            dt.Columns.Add("ID", typeof(int));
            dt.Columns.Add("Name", typeof(string));
            dt.Columns.Add("Description", typeof(string));
            dt.Columns.Add("Address", typeof(string));
            for (int i = 0; i < 10; i++)
            {
                DataRow dr;
                dr = dt.NewRow();
                dr["ID"] = i;
                dr["Name"] = "Some Name " + i.ToString();
                dr["Description"] = "Some Description " + i.ToString();
                dr["Address"] = "Some Address " + i.ToString();
                dt.Rows.Add(dr);
            }
        }
        public DataTable DataSource
        {
            get
            {
                return this.dt;
            }
        }
    }
    protected void Populate_Click(object sender, EventArgs e)
    {
        SampleDataSource s = new SampleDataSource();
        GridView1.DataSource = s.DataSource;
        GridView1.DataBind();
    }
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GridView1" Width="50%" runat="server">
        </asp:GridView>
        <asp:Button ID="Populate" runat="server" Text="Populate" onclick="Populate_Click" />
    </div>
    </form>
</body>
</html>

SamplePage2.aspx in VB.NET

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
    Public Class SampleDataSource
        Dim dt As DataTable
        Public Sub New()
            Dim i As Integer
            dt = New DataTable
            dt.Columns.Add("ID", GetType(Integer))
            dt.Columns.Add("Name", GetType(String))
            dt.Columns.Add("Description", GetType(String))
            dt.Columns.Add("Address", GetType(String))
            For i = 0 To 10
                Dim dr As DataRow
                dr = dt.NewRow
                dr("ID") = i
                dr("Name") = "Some Name " + i.ToString()
                dr("Description") = "Some Description " + i.ToString()
                dr("Address") = "Some Address " + i.ToString()
                dt.Rows.Add(dr)
            Next
        End Sub
        Public ReadOnly Property DS() As DataTable
            Get
                Return dt
            End Get
        End Property
    End Class
    Protected Sub btnPopulate_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim sd As New SampleDataSource()
        dgSample.DataSource = sd.DS
        dgSample.DataBind()
    End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="dgSample" width="50%" runat="server"></asp:GridView>
        <asp:Button ID="btnPopulate" Text="Populate" runat="server" onclick="btnPopulate_Click" />
    </div>
    </form>
</body>
</html>

I know this might not be helpful to most of you at all since this code doesn't do much by itself. I have certain samples to do, and may be in future, this post will help me and some of my folks here while troubleshooting!

Until next time
Rahul

Windows Powershell is for Administrators... is it really?

For those who are unaware, Windows Powershell is a new Windows command line shell with System Administrators being the target audience. That's the reason why I kept myself away from this tool for a pretty long time (I am more of a Developer than an Administrator). Then one day, I found myself enrolled for a training in Powershell

Before going to the training I was preparing myself to get the basic background of what it was and stuff, and now I feel that I was really dumb to keep myself away from such a cool new thing for such a long time.

Download it from this link and read the manual. The manual is pretty good.

The POWERSHELL includes an interactive prompt and a very robust scripting engine. It is built on top of the .NET Framework 2.0 and instead of accepting and returning text, it has the power of accepting and returning .NET objects. If you think about it, you will notice that most shells including CMD.exe in Windows... SH, KSH, CSH and BASH Unix shells operate by executing a command in text format which could be calling external commands like "XCopy.exe" and getting the output (or doing the task) for you. There were a few inbuilt commands as well like dir, copy, etc. but that's about it. If you need more utilities, you need to create additional programs and call them appropriately. Windows Powershell brings the concept of cmdlets (pronounced "Command-Let"). Please read the documentation to know more about it. In contrast to a normal shell, PS gives you access to File System + other data stores like registry, digital certificate stores, as easily as you can access the file system.

After you install it... you will find it pretty simliar to the command prompt. Don't let this look deceive you. There is a powerful beast inside this interface.

Start with get-help get-* and you will see the list of Get commands it throws at you.

In PS, the convention is pretty simple...

Similarly, have a look at some of the other outputs... I find it interesting enough to start my journey into PowerShell.

My journey has just begun, and I have subscribed to the following...

http://blogs.msdn.com/PowerShell/

Using powershell from IIS/.NET troubleshooting perspective would be my agenda in the coming time. This blog post is my first on Powershell, and that too before writing any real cmdlets. Pretty soon, after I get comfortable with creating the real cmdlets, I will share them with you as well. Stay tuned...

Before I end this post, here is what you can do for today (if you haven't already).

1. Open the PowerShell's Shortcut property.
2. Set the Shortcut key to CTRL+Shift+P (or anything else of your choice) and click Ok.

3. Whenever you want to open a PS command prompt... all you have to do is to press your shortcut key

Cheers,
Rahul

Quote of the day:
I have enough money to last me the rest of my life, unless I buy something. - Jackie Mason