New session per browser tab/window in ASP.NET MVC 3 app - asp.net

I need to have a new session per browser window/tab. I am aware of the fact that ASP.NET assigns one session per process. I am also aware that browsers share this session between all open tabs/windows of the app. However, I need to come up with a way to create a new session for a new tab/window.
Cookieless session-state is not an option also. I already looked at that. I am looking to keep URL's clean.
I looked at the following solutions.
1) asp.net - session - multiple browser tabs - different sessions?. This solutions suggests using IsPostBack property, which is not available in MVC.
2) https://sites.google.com/site/sarittechworld/track-client-windows. This one looks very complex and I don't fully understand the javascript magic that is happening in it. I don't want to put in a solution that I don't understand. Also, I am not fully aware of any security holes that this solution may create.
Can someone point me in the right direction?

The only way to achieve this is to append the session id in the url which is what cookieless sessions are intended to do. Unfortunately you seem to have ruled out this possibility due to the ugly urls it produces.

I've created a NuGet package called ASP.NET MVC Conversational Session. Here you find more information: http://blog.micic.ch/net/asp-net-mvc-conversational-session
I released the first version yesterday. Have a look at the demo code or download the demo solution and let me know if there are things to improve. :)
EDIT: By default: The "identifier" is passed via URL when you use the appropriate extension method in the View. But you can add the identifier on your own. It gives you more flexiblity. (For example when you have links which are not generated via #Html.ActionLink.. etc.)

Related

Avoid session spamming from crawlers and other bots

Since crawlers and most bots don't use cookies, they create a lot of unnecessary sessions. At least for identified bots we'd like to avoid creating a session.
We're using SqlInMemoryProvider which doesn't appear to be open source.
https://cloudblogs.microsoft.com/sqlserver/2014/07/10/new-asp-net-session-state-provider-for-sql-server-in-memory-oltp/
Is there a way to run code to intercept session creation for certain conditions? My guess is one would need access to the custom SqlInMemoryProvider to achieve that. But maybe i'm missing something. ;)
Technology: Asp.Net Webforms, don't bother advising for MVC, thanks ;)
Answer for other people in my situation.
There are no hooks.
Everything needs to be done in the custom session-state store provider.
It's possible to use the free disassembler DotPeek by JetBrains.
One can dissassemble an existing state provider to c# code.
After that the code can be extended, for example detect known bots with a library (for example) https://github.com/totpero/DeviceDetector.NET and prevent such sessions from being created.

How can make a query string like facebook.com/username?

I am building a website with asp.net. But I have an issue: I want to make user profile page link like in facebook.
For example,
"hostname.com/username" instead of "hostname.com/profile.aspx?something=something"
How can I achieve this?
Thank you for your time and valuable answers.
That feature called "URL Routing". If you are using MVC, then MVC Framework has That feature included. But if you are using Web Forms application, then You have to do this manual.
For Web Forms application, You can use Nuget Package Microsoft.AspNet.FriendlyUrls to make your application so that it generate url's what you want.
Refer http://www.devcurry.com/2013/05/friendly-urls-in-aspnet-web-forms.html
http://www.hanselman.com/blog/IntroducingASPNETFriendlyUrlsCleanerURLsEasierRoutingAndMobileViewsForASPNETWebForms.aspx (This is microsoft suggested)
This is typically done with a framework of some kind, but the concept it fairly simple --
If you're trying to do this quickly, you'll want to do your research on which one to use, but I'll explain the principle that makes it work -
In your server config (like an .htaccess) - you will rewrite the requests for *.aspx files go to a central index.aspx - this file then bootstraps your index however you want -
In your case, it would take the /username portion and query the database for a user with that username, fetch the associated data, and do whatever with it.
It's a relatively simple concept, and you could write something of your own device to bootstrap the request to your code, but you're probably better off looking for some (micro)framework that handles all that for you...
Good luck - !

ASP.NET Session Mix-up using StateServer (SCARY!)

We store two objects in session. Somehow, one of the objects from another user got loaded into a different user's session. The user should have had no access to this particular data, and as soon as they saw it they knew something was very wrong.
We have visual proof of the data that was presented to him, and there is certainly no way it could've happened unless the sessions got mixed up. This is a very scary situation which we can not figure out (we can not reproduce it). The only answer for us is to blame ASP.NET StateServer for mixing the session variables up, which is completely unacceptable and puts us in a bad position.
Our applications are ASP.NET 2.0 apps running on Windows Server 2003 with IIS6, using the StateServer cookieless="false" session mode and FormsAuthentication.
Has anybody else had this problem? How can we resolve it?
We ran into this exact issue in my previous company and took 3 weeks to debug it. ASP.NET was giving a user someone else's session state. It was really impossible to duplicate in a debug environment.
The fix when we found it was just something in web.config. I don't fully remember it, so I spent some time googling. I believe the issue had something to do with output caching. Take a look at this article under "Sessions and Output Caching".
http://download.microsoft.com/download/3/a/7/3a7fa450-1f33-41f7-9e6d-3aa95b5a6aea/MSDNMagazineJuly2006en-us.chm (the article is titled Keep Sites Running Smoothly By Avoiding These 10 Common ASP.NET Pitfalls by Jeff Prosise in July 2006 edition of MSDN magazine)
If that sounds like your scenario, then the fix might just be disabling the enableKernelOutputCache option in web.config.
Good luck.
Look for bugs in your own code first - this is by far the most likely explanation. E.g. using static fields or other shared memory such as the ASP.NET cache for user-specific data.
Possible answer - similar isue reported using cookieless session state.
session showing something wrong
Edit - Added
Another possible answer:
An ASP.NET page is stored in the HTTP.sys kernel cache in IIS 6.0 when the ASP.NET page generates an HTTP header that contains a Set-Cookie response
How many times did it occur? Did you check for users using browser back or sending links to each other with session ids?
One way to check for sure about State Server bug is to switch to another session manager, fallback to in-proc if you can or use SQL Server but would be better to find a way to reproduce the bug it first so you could test it.
Could the two crossed users both be using the same cacheing proxy? If so, then one user might see data that was cached for another user if the URLs matched, especially if the proxy isn't well behaved.
Wasn't this the main problem with the Google Web Accelerator project (now discontinued)?
Had this problem, turned out to be an OutputCache attribute on a partial view.

Code reusability - App_Code or BIN or UserControls?

I recently had a discussion on another forum with another developer and the topic was Code Reuse in ASP.NET. The stated scenario was that he needs to update code frequently on Production servers during server uptimes, and this results in Session getting reset for all users. He is avoiding putting shared code or classes into the App_Code folder or precompiled DLL's into the Bin folder because any updates will also refresh the Session.
The solution he has come up with is to put his shared code into UserControls and reference them wherever required. This enables him to update only the UserControl files which would be recompiled dynamically on next request without forcing a Session restart. Note that the Usercontrols are not intended to have any UI, they probably only house some business logic.
I tried to convince him against this because it felt intrinsically wrong to me - but I could not provide any hard facts to support my claim that this was a very bad way of doing things. The only thing I could think of is that it violates the principle of separation of business logic from UI. Am I grossly mistaken or are there concrete reasons why this should not be done? Links or examples would be helpful.
Note: Using out-of-process Session state is not an option at present, nor have they been able to decide on scheduled downtimes. Also, since this is a site under active development, they don't seem to be using any sort of professional deployment model yet.
Thanks in advance.
Edit: Additionally, it would be helpful if someone could clarify exactly why the Session restarts in the above mentioned cases.
It does seem like an unusual approach, and persistent session is the obvious answer. Assuming that reasons not to use persistent session are legitimate, sometime you just have to go with whatever works. I'd make a point of clearly documenting in the source files the unusual use of usercontrols and live with it.
To answer the why does session get reset edit. With in process session all the session data is in memory as part of your application. Various changes to the web site (e.g. web.config and others I don't recall off the top of my head) cause the application to restart wiping out all current state in your application. Persisting to SQL or the out of process session state server would allow the application to reset and lose any state without affecting the session data.
It sounds like the main problem is that he's updating production code too frequently. Other than that, UserControls seem like a perfectly reasonable place to put business logic, especially if you have a good naming convention for them or can put them in a common folder.
May i ask, why isn't out-of-process session state an option, really?
Since this guy seems to put in so much effort to get around this "problem", wouldn't he be better off looking at better solutions? out-of-process session state is the only good solution.
I'll agree with Dennis, there are really no issues moving from inproc to the state server. Not sure what your dev/deployment platforms are, but they should include a session state service - start that up, change your web.config, and the problem is solved.
it's a clever (and ugly) solution to a common problem
The main problem is the architecture of such system; the code that needs to be updated can be put on a different service outside his web app, his code behind can then call these services, and the services can be updated when needed without affecting the web app
Every base has been covered already, but I really hate bad practices like this. If the guy can't simply change to a state server to fix the problem that he has, then he doesn't really deserve the help. What would happen if he put his class in the root folder of the project and compiled it independently? Either way, I would think this guy is a bad developer for not thinking about scalability, and not planning for downtime. What I'm guessing is he doesn't have a development environment available. Tsk tsk tsk.
As an answer to your question, as stated by everyone else, put the code in a user control, and document well.

Single ASP.net site with Multiple Instances & web.configs

We have a legacy ASP.net powered site running on a IIS server, the site was developed by a central team and is used by multiple customers. Each customer however has their own copy of the site's aspx files plus a web.config file. This is causing problems as changes made by well meaning support engineers to the copies of the source aspx files are not being folded back into the central source, so our code base is diverging. Our current folder structure looks something like:
OurApp/Source aspx & default web.config
Customer1/Source aspx & web.config
Customer2/Source aspx & web.config
Customer3/Source aspx & web.config
Customer4/Source aspx & web.config
...
This is something I'd like to change to each customer having just a customised web.config file and all the customers sharing a common set of source files. So something like:
OurApp/Source aspx & default web.config
Customer1/web.config
Customer2/web.config
Customer3/web.config
Customer4/web.config
...
So my question is, how do I set this up? I'm new to ASP.net and IIS as I usually use php and apache at home but we use ASP.net and ISS here at work.
Source control is used and I intend to retrain the support engineers but is there any way to avoid having multiple copies of the source aspx files? I hate that sort of duplication!
If you're dead-set on the single app instance, you can accomplish what you're after using a custom ConfigurationSection in your single web.config. For the basics, see:
http://haacked.com/archive/2007/03/12/custom-configuration-sections-in-3-easy-steps.aspx
http://msdn.microsoft.com/en-us/library/2tw134k3.aspx
Example XML might be:
<YourCustomConfigSection>
<Customers>
<Customer Name="Customer1" SomeSetting="A" Another="1" />
<Customer Name="Customer2" SomeSetting="B" Another="2" />
<Customer Name="Customer3" SomeSetting="C" Another="3" />
</Customers>
</YourCustomConfigSection>
Now in your ConfigSection Properties, expose Name, SomeSetting, and Another. When the Property is accessed or set, use a condition (request domain or something else that uniquely identifies the Customer) to decide which to use.
With the proper implementation, the app developers don't need to be aware of what's going on behind the scenes. They just use CustomSettings.Settings.SomeSetting and don't worry about which Customer is accessing the app.
I know it might seem annoying, but the duplication is actually a good thing. The problem here is with your process, not with the way the systems are setup.
Keeping the sites separate is actually a good thing. Whilst it looks like "duplication" it's actually not. It's separation. Making changes in the production code by your support engineers should be actively discouraged.
You should be looking at changing your process to change once deploy everywhere. This will make everything a lot easier for you in the long run.
To actually answer your question, the answer is no, you can't do it. The reason is that web.config isn't designed to store user level settings, it's designed to store per application instance settings. In your case, you need an application instance per user which means separate config files.
For your system to work, you need to be able to preemptively tell the application which config file to use, which isn't possible without some sort of input from the user.
Use an external source control application and keep rolling out updates as required.
It isn't really a good idea to let your live site be updated by support engineers in real time anyway.
Depending on what is actually in the web config, and what settings differ between customers, you could opt to use a single web config, and store other customer specific configuration options in a database or some other custom xml/text file. As long as the specific customer settings in the web.config don't have to do anything with how IIS operates, and you are just using it to store values, then this solution might work out well for you.
Thank you all again for your answers. After reading through them and having a think what I think I will do is leave the multiple instances alone for now and I will try to improve our update process first. then I will develop a new version of the application that has the user configuration information in the database layer and then pick the user based on the request domain or URL as someone suggested. That way I can have a single application instance supporting multiple different client configurations cleanly.
As most of the client configuration data is really presentation or data source related, nothing complicated. I think we ended up with multiple application instances mostly because the original programmer hadn't been expecting multiple customers and didn't design for that so when someone came along later and added a second customer they just duplicated the application which is wasteful as each instance is about 99.99% identical to the original.
I am implementing this as we speak.
In the main web.config, I have 1 item per installation. It points me toward the custom config file I built for each client (and toward the custom masterpage, css, images, etc).
Using WebConfigurationManager.OpenWebConfiguration, I open the new webconfigs in their subdirectories. I determine which one to use by using System.Web.HttpContext.Current.Request.Url.OriginalString, and determining the uRL that called me. Based on that URL, I know which web.config to use.
From that point forward the clients all use the same codebase. They have their own databases too.
The idea of having to update 30-40 installations when we make an update scares the death out of me. We do not want to support 30-40 codebases, so there won't be customization beyond the master page, css, and images.
I wrote a custom class lib that knows how to switch to the proper webconfig, and read the custom section I built with all our settings.
The only issue I have now is the FormsAuthentication Cookie. I need to be able to switch that as well. Unfortunately, the property for the name is read only
If I understand correctly, it sounds like you have multiple deployments (one for each client) where the only difference is the web.config, right?
First off, although I don't know your unique situation, I would generally urge you to stay with separate installs. It usually allows much more flexibility. Off the top of my head: are you ever going to have customizations, or different clients running different versions? Are you sure? The easiest way to stay flexible here is to keep going with separate installs.
In my opinion, it isn't ugly at all if your practices are aligned properly. Based on some things you mentioned, you have trouble in that area - obviously, possible source control buy-in/training issues. But you are aware of that. I would also take a hard look at your deployment procedures and so on. I have a feeling you might have further issues in that area, and I mean absolutely no offense.
That said, let's say you want to move forward with this.
You didn't say whether all the clients share a single common database, but I'm thinking no, since designing that type of system is often not worth the extra complexity (which can be severe in systems of any size) so people often opt to keep them separate.
What that means is that you have store your connection string somewhere. Usually that would be web.config... So that seems to break our plan.
Really, the apparent elegance of this situation is almost always wildly offset by the challenges it introduces. If I thought about it hard enough, I could maybe find a way around this by introducing another database that intelligently manages connection strings or maybe delving into keeping all your login info directly in web.config (which is possible but... not ideal), however my gut says the work will be wasted because some day you will end up going back to how you're doing it now.
Also: changing code directly in production is obviously not the best practice here. But you if you are on a monolithic shared platform with any amount of traffic, that can never ever ever happen. Food for thought.
Let me know if I'm missing something!

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