Solved

VB.net Webclient - trying not to cache webpage

Posted on 2015-02-12
4
218 Views
Last Modified: 2015-03-06
The main thing I am trying to do is get page load time of a website.  But it seems to work the first time I put a new website domain in, but run it again it appears to be a lot faster (cache). I dont want that, I want it make sure it does not load cache version.  Any ideas on what I did wrong below?  I'm also open to a better way to get total page load time.

Dim sw = New Stopwatch()
sw.Start()
Dim policy As New RequestCachePolicy(RequestCacheLevel.NoCacheNoStore)
Dim sourceString As String = New System.Net.WebClient().DownloadString("http://www.google.com")

 sw.Stop()
 Dim ts As TimeSpan = sw.Elapsed
        txtWebSource.Text = sourceString
        ' Format and display the TimeSpan value. 
        Dim elapsedTime As String = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 1)
        lblPingTime.Text = elapsedTime

Open in new window

0
Comment
Question by:keith1001
  • 2
  • 2
4 Comments
 
LVL 35

Expert Comment

by:Kimputer
ID: 40605340
You didn't actually use the policy. Make sure WebClient.CachePolicy is used in your code.

Please note that the numbers AFTER the first run are pretty accurate, even if you DIDN'T use the policy (I only mentioned you didn't use it so in your further .net programming, setting a variable and not using it later is senseless). Cache isn't used (you can capture your network traffic, you will see it is indeed reloaded from the server every time).
Since you used a quick website, you would think it's not accurate. If you tested on a foreign slow website, you probably wouldn't notice it.
Why the first run is always a bit higher has probably something to do with the .Net framework.
0
 

Author Comment

by:keith1001
ID: 40607298
I have tested it on bigger sites, and the 1st run is always longer by a couple seconds.

So what do I need to add the set the policy to NoCache or Reload?
0
 
LVL 35

Accepted Solution

by:
Kimputer earned 500 total points
ID: 40607559
Read my message again. I said even if you didn't use the policy, the results will largely STILL be the same (first run longer). You should discard the first result, it's a .NET thing. All subsequent timings are correct.
So Policy to NoCache, Reload or NOT SETTING it, it doesn't matter. Your application WILL get the files from the server, NOT from disk or memory.
0
 

Author Closing Comment

by:keith1001
ID: 40650492
Sorry for long time for accepting, fighting some health issues unfortunately.
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This tutorial demonstrates one way to create an application that runs without any Forms but still has a GUI presence via an Icon in the System Tray. The magic lies in Inheriting from the ApplicationContext Class and passing that to Application.Ru…
Creating an analog clock UserControl seems fairly straight forward.  It is, after all, essentially just a circle with several lines in it!  Two common approaches for rendering an analog clock typically involve either manually calculating points with…

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question