So I am new to the whole datacache thing. I am building an app for a client who has potential to grow substantially so I am using the datacache instead of Session variables so that I can have multiple servers.
I have been in development mode and this has worked just fine, but it has just been me.
Now we are testing and completely new people on a computer that have never been to the site before are being recognized as another user somehow...
I do use cookies to remember a user, but these guys are coming in for the first time so that can't be it. Never had this problem with Session variables so I must be doing something wrong with the datacache.
Why does the datacache confuse the users? How do I prevent this?
Thanks!
David
cache = server level, session = user level. Your server is saving the cache data and passing it along to the users. If you have intentions of having multiple users connected, and storing separate data for each, sessions is actually the correct way to do it.
As for performance, yes there will be a slight performance hit, but it shouldn't be too drastic unless you've got a massive amount of users hitting the site at one time or you're storing huge amounts of data to the session.
You need to use Session to store a logged in users credentials and other session specific information. Datacache is used to store application wide data that can be quickly accessed, things like xml files used on the website or perhaps a dataset used by anyone on the website. Session is a unique id and "thread" for each user for their specific user name and all other information related to their logged in id.
Related
I wanted to try this code/solution to my ASP.net (VScode 1.69.1) but I am not sure where is the "Global.asax". Anyone know how I can apply the code below to asp.net core?
https://teknohippy.net/2008/08/21/stopping-aspnet-concurrent-logins/
I would not advise you to use that code, it wasn't even good advice back in 2015, but we can explore the concept and it's flaws which might help you come to a better overall solution.
This post will provide some context to the issue: Single Instance Login Implementation but is not a direct duplicate. The original source article does actually go into better detail about the general issues with this approach: http://www.nullskull.com/articles/20030418.asp
Using an In-Memory cache is not a viable option for production as multiple instances of the application would not share the same cache, especially if the application is hosted across multiple servers or serverless infrastructure that is configured to scale out beyond a single instance.
If all you want to do is block new logins, if the user is already logged in, then a server-based or cache concept itself is the right solution, conceptually to enforce a single instance across different browser sessions and across multiple servers will require that there is a server-side cache or store that holds the source of truth for all active connections. This could be in the form of a database or a distributed cache like REDIS.
But this is not a practical model for how users actually use their browsers and devices. Instead of blocking new logins, it is more practical from a user point of view to expire or force close the existing logins. The problem with only blocking new logins is that if the user doesn't have access to the original browser session that holds the login, then there is no way to log out the previous session, you would have to wait for it to timeout. The challenge with being able to expire a login session is that your clients and the server code must be designed to round-trip to the session store to validate the session token. Most default JWT or even cookie implementations do not do this, they will rely on the expiry or validity information in the token itself, and bypass consulting the store.
Instead of the article you have found, please try these resources:
ASP.NET Core security topics
Can I force a logout or expiration of a JWT token?
JSON Web Tokens (JWT) are Dangerous for User Sessions—Here’s a Solution
I'm currently trying to set up a session management interface for users to essentially log out their sessions that may be active on other devices. However, I'm still somewhat new to Asp.Net Core 2.1 and am having trouble finding good documentation on the subject.
I thought about using the distributed SQL server cache system. However, after further inspection, I found that the keys for the distributed cache are not equal, as they shouldn't be, with the session id.
I also tried writing some middleware that stores the session id in a separate table with a many-to-one relationship with the user table. This table would have a sliding expiration dates and a tokens. If the session had a token, the session would be persisted.. My thought was to assign a token to the client using a cookie. That way if their session expired, it would lookup the session with the cookie token and, if one existed, log the corresponding user in. Then it would copy over the token and delete the old session. Kind of like a 'remember me' system. If the token is null and the session time was expired, it would be disposed of. If no session was found, or the user field is null, it would log the user out. If duplicate tokens were found, it would log all of the sessions with the corresponding token out. However, I'd rather use some kind of built in feature, if it exists, to minimize the risk in opening up unwanted security vulnerabilities.
I've also found examples where you can log another user out... But, because Asp.Net Identity is cookie-based, it allows the user to continue to use the site until their cookie expires... This would be undesirable in this scenario.
I know that Asp.Net had the IHttpSessionState, but I've been unable to find a similar interface in Core. Unfortunately, most solutions I've found either point to implementing a custom-made system, or they just show how to log the current session out.
Basically, is there already some kind of mechanism in Asp.Net Core that already implements something like this? If not, is there any specific interfaces that I should be researching and trying to implement? If not, should I resort to writing my own system? If so, are there any holes in my logic above?
Here's an example of what I'm talking about, pulled from Facebook's account management. I know that it's a much larger scope website, but I wouldn't think that such a feature would be extremely hard to integrate? Might be wrong though...
(Redacted some personal info)
I'm re-writing a website from the ground up for azure. Each user has ownership of a number of objects, and has a number of permissions. Together, these determine what they are authorized to do. The question is, how should this information be stored. I want to do the authentication myself, using custom logic.
For performance reasons, I'd like to cache these authorization lists for each user once they're logged in. Can someone give me a sample for how to store & access this session information securely and efficiently.
Edit
I looked into the App Fabric Access Control, but that seemed overkill as I was going to have to create a separate site for authentication, which doesn't seem to make sense. Would the claims based authentication make sense separately though? How would you do that if it does?
Would it make more sense to just keep the username in a cookie in the traditional way and then re-query table storage with each request to get the permissions etc.? How would storing the username work in Azure?
Cost is a big factor here as it's a very small site (by azure standards) but I want high performance for a small number of users.
If you want to run with a reasonable amount of availability you need to run your site with two instances. If you're running with two instances you need to use a session provider that's no the default InProc one. Your choices are:
AppFabric Caching (which you don't want to use because it's too expensive, fair enough)
Azure Storage Session Provider. Don't use this. It's an interesting experiment, but it's only sample code, it's slow and doesn't cope well in production.
SQL Server session provider.
If the permissions for a user weren't going to change while they were logged in, you could just store their permissions in session. This will probably be fast enough. However this information will need to be read from SQL for each request that uses session and it is overhead.
If you wanted to make things faster you could just store the user ID in session and load the permissions into a static dictionary (keyed on user ID) when needed. These items will need to be expired after a certain amount of time or lack of use.
Well, you could use the Azure App Fabric cache to store the session info. ASP.Net can be configured to use it as the backing store for its session state as like a normal custom session state provider.
This article from MSDN shows you how to configure it:
http://msdn.microsoft.com/en-us/library/windowsazure/gg278339.aspx
From your code you just use the normal ASP.Net way to get/set the state.
Be aware though - it could be expensive ($45/month for 128MB of cache).
My web application has 2 types of users: non-authenticated visitors and authenticated customers. I'd like the pages that visitors see to work with InProc session and, as soon as a user moves to the the login page, create a new session that works using SQL server session mode.
Is this possible and if so, how is it implemented?
Thanks for your suggestions.
You can only have one sessionMode per Application (Virtual Directory).
You can make 2 separate applications with single-sign-on , to the user it would look like 1 Application.
That is not 100% the same, authenticated users that visit the public pages would use InProc. Up to you if that matters.
On the other hand, are you sure this is worth the effort at all? You can't use the Session for data in a multi-server + InProc scenario anyway (that may depend on your IP setup). And storing (small amounts of) data in the SqlServer shouldn't be much of a problem.
I am creating a website on ASP.Net in which a user logs on and I need to store the user specific data (plus some extra data) somewhere so that all the pages in my website can readily access the data.
At one time many users could be accessing the website and every user will have his own specific data.
Currently I am using sessions to store the data after login and accessing the data on different pages as and when needed. I am also using session to pass data from one page to another. I also don't want to use cookies as many companies don't allow cookies to be created.
I understand that this is not the best practice. Can you guys suggest what would be the best way to manage the data?
Thanks,
Abhi.
Sessions are not necessarily a bad way to go. Ensure that data kept in the session is as concise as possible, and that your application will support all environments that it may be deployed into.
Also remember that Sessions do not provide data persistance once the session has been expired, so if you require data persistence, then a database would be more suitable.
This is what MS says about it, http://msdn.microsoft.com/en-us/library/ms178581.aspx:
"SessionID values are sent in clear text, whether as a cookie or as part of the URL. A malicious user could get access to the session of another user by obtaining the SessionID value and including it in requests to the server. If you are storing sensitive information in session state, it is recommended that you use SSL to encrypt any communication between the browser and server that includes the SessionID value."
As long as you use a save connection you should be fine
ASP.NET already provides you with information about the user through the IPrincipal interface and the User property.
If you need extra information about each user, you can use these to implement a User Context.