Содержание
Code Listing 5-1 shows the configuration settings from machine.config that specify the default settings for session state. Notice in the above MVC controller, we attempt to create or read a MagicSpell object from the session upon loading the MVC view page. We’ve also included a button on the page which calls the Submit() method via an AJAX callback, returning a PartialView with the same content.
Important Use integrated authentication rather than store SQL Server credentials within your configuration file. If you decide to use SQL Server user names and passwords, do not use the system administrator account. Instead use an account that has only the necessary access to the database object required for the operations .
SQL Server is an enterprise-class database solution optimized for managing, storing, and retrieving data quickly and efficiently. In a clustered environment, SQL Server can be configured to failover. For example, when the clustered production SQL server fails, a backup can take over. When ASP.NET is configured to use state server for out-of-process session, it uses a TCP/IP address and port number to send HTTP requests to the state server . We recommend SQLServer for out-of-process session state because it is just as fast as StateServer and SQL Server is excellent at managing data. Furthermore, ASP.NET can communicate with SQL Server natively (meaning internally, using the System.Data.SqlClient libraries), and SQL Server can be configured to support data failover scenarios.
Create a class with two String members, and store that class object in a session variable. If you have an ASP.NET session variable (e.g. an ArrayList object) that is not one of the “basic” types, ASP.NET will serialize/deserialize it using the BinaryFormatter, which is relatively slower. Important Ensure SQL Server Agent is running before running the SQL Scripts.
In particular, we’ll focus on implications of Session State and potential solutions for scaling session across multiple processors and servers. We’ll also view an example web application utilizing Session to examine the differences of running InProc versus OutOfProc in a web garden/web farm environment. InProc – Session state will be lost if the worker process (aspnet_wp.exe) recycles, or if the appdomain restarts.
This indicates the same worker process within the web garden has served us the page consecutively. This would be same result as if IP affinity were configured for the web garden or web farm. If we continue to refresh the page, we would expect asp net usage the same magical spell to display with the view count incremented accordingly. Consider the case where the above C# ASP .NET web application has grown to the point where a single web server is no longer sufficient to serve all requests.
While this is not possible i prefer to only specify the key once and then forget about it whereever i can. Putting it in a constant and then using the Extension Methods could be OK, but IMHO not that nice. Admittedly, I am not that familiar with session management in asp.net, so my concern with threading issues might not be valid. There is no timeout specified for SessionId cookie and they are deleted when the Browser session ends. The cookie is sent to the user’s computer and it contains information that identifies the user.
Asp Net Session Dataset, Datatable, And net Class Storage
The first line of code takes the value of the Name textbox control and stores it in the Session object. By specifying the code of Session[“Name”] , we are giving the property a name called “Name.” By specifying a name for the property, it becomes easier to retrieve it at a later point in time. In our example, we are going to use the Session object to store the name entered in the name textbox field in the page. We are then going to retrieve that value and display it on the page accordingly. This stores the value in a Session object and the ‘key’ part is used to give the value a name.
We’ll create this object initially when the ASP .NET MVC Razor view page loads. We’ll maintain a count of how many times the object has been viewed in the same session. The larger gain for web gardens is not speed, but rather robustness. If one of the worker processes hosting in a web application goes down or freezes, in a single worker-process environment, the entire web application would go down. However, in a web garden scenario, the remaining worker processes could continue serving requests, even as the faulty worker process is taken down and restarted.
Store And Retrieve Session Variables
In cases in which SQLServer is not available, StateServer works well, but it unfortunately does not support data replication or failover scenarios. Requests from each web server for session data can pull from the database to retrieve session information and resynchronize. A benefit to SQLServer OutOfProc session state is that it allows for fail-over SQL servers and backup of mission critical information.
A web garden is a hosting environment, on a single PC, consisting of multiple worker processes within a .NET web application pool. Typically, a web garden is utilized on a multi-core (multi-processor) PC or web server. Ideally, each worker process within the application pool would execute on an individual processor, helping to achieve more robust execution and processing of the C# ASP .NET web application threads. When using out-of-process session, ASP.NET makes two requests to the out-of- process session store for every one page requested . When the request first starts, the session state module connects to the state store, reads the session state data, and marks the session as locked. At this point the page is executed, and the Session object is accessible.
It is common to abstract a layer of the web application design for handling data processing and database activity. This layer can be abstracted further into a WCF web service layer, hosted and executed within its own web server, separate from the main web application’s web server. Taking this one step further, the main web application can execute on its own web farm and load balancer, while the WCF web service executes on its own web farm and load balancer.
Throw Another Web Server Into The Mix
To configure SQL Server to support ASP.NET session state, either open the InstallSqlState.sql file in isqlw.exe , or use the command-line tool osql.exe. To use SQL Server Query Analyzer, from the Start menu, navigate to \All Programs\Microsoft SQL Server\Query Analyzer. Note that clustered SQL Server scenarios are not supported out of the box for ASP.NET session state. To enable the clustering or replication features of SQL Server, session data must be stored in a non-tempDB table. These events can be programmed in either global.asax or within an HTTP module. We often get asked why we store session data using tempdb vs. a table.
In this scenario, an additional web server would be needed to offload the original. StateServer – When storing data of basic types (e.g. string, integer, etc), in one test environment it’s 15% slower than InProc. However, the cost of serialization/deserialization can affect performance if you’re storing lots of objects. The StateServer out-of-process mode relies on a running Microsoft Windows NT Service as well as changes to the default configuration settings.
For instance, if you had a login page which has 2 textboxes, one for the name and the other for the password. When you click the Login button on that page, the application needs to ensure that the username and password get passed onto the next page.
- If you attempt to build a site that uses frames, and each page within a frame requires session state, the pages will execute serially.
- Yes, but then i had to post a solution with 6 or 7 classes plus unit tests.
- Requests from each web server for session data can pull from the database to retrieve session information and resynchronize.
- With terminology out of the way, we can discuss the solutions for migrating a C# ASP .NET web application from the default InProc Session state to an OutOfProc or distributed session state.
- In your example, you first call MySessionVariables.UserGroups.HasValue and then MySessionVariables.UserGroups.Value.Contains(“Admin”), both calls result in call to GetInternalValue.
- We recommend SQLServer for out-of-process session state because it is just as fast as StateServer and SQL Server is excellent at managing data.
As the user accesses the web application, he’ll be served from one of the web servers for the initial request. Session data will be saved and read from the web server and the initial request will process as expected. However, on the second request, it is possible the user will be served from the second web server. In this case, since the second server has its own Session state, the data saved from the first request will be missing. As the user’s requests alternate between the two servers in the web farm, Session data will become inconsistent, leading to incomplete, corrupt, and missing data within the web application.
Forget_code Modelscategoryviewmodel
If you must use SQL Server credentials, ASP.NET 1.1 supports storing credentials securely. ASP.NET session state supports two out-of-process options, state server and SQL Server . Each has its own configuration settings and idiosyncrasies to contend with, such as managing stored types. The ASP.NET State Service is recommended for medium-size Web applications. For enterprise-size or highly-transactional Web applications, SQL Server is recommended. If the account has the necessary permissions, integrated authentication should be used.
Asp Session Object
If no value is present, a new value is saved into the Session state. The variable is persisted in the web server’s memory and held for the duration of the timeout value, specified in the web.config. InProc – Fastest, but the more session data, the more memory is consumed on the web server, and that can affect performance. A cookie is a highly contentious, much debated feature supported by all browsers that allows the server to store a small amount of data, private to the server, on the client. Upon each client request to the server, the browser sends along any cookie data belonging to that server.
The majority of C# ASP .NET web applications are often developed with the intention of running in a single web server environment. They’ll often take advantage of ASP .NET’s Session State to store variables and data on the server, per user. As an ASP .NET web application grows in usage and popularity, scalability issues may arise, as the single web server is brought to its maximum capabilities.
Scaling A Web Farm With Web Services
The original design goal was to ensure that SQL Server state was fast, and because tempdb is memory-based, SQL Server state would be very fast. However, since SQL Server is so optimized, storing the data in non-temporary tables proved to be nearly as efficient. (SQL Server is super aggressive about keeping frequently accessed data in memory.) In retrospect, using tempdb probably wasn’t necessary. Important Don’t use the Session_End event; it can be called only for sessions created in the InProc mode. The event is not raised for sessions created in one of the out-of-process modes when sessions are abandoned.
Growing a web application’s architecture beyond a single web server design and utilizing the power of a web farm can greatly enhance the reliability and performance of a web application. However, for some high frequency and traffic-intensive web applications, a single web farm alone may not be enough. In these cases, the web application architecture can be expanded to span multiple web farms, particularly through the usage of WCF web services. Web farms are often used in enterprise environments to provide fail-safe and reliable services for highly-used web applications. Web farms offload incoming traffic by alternating between servers and by evenly distributing web application load. Additional web servers may be added or taken away from a web farm to increase or decrease the web application performance, as necessary for the target environment.
In your example, you first call MySessionVariables.UserGroups.HasValue and then MySessionVariables.UserGroups.Value.Contains(“Admin”), both calls result in call to GetInternalValue. Why not have a local variable to store the retrived value in, then you would only have to do that once every http request. The “AddSession” method has one overload method, which accepts various session options such as Idle Timeout, Cookie Name and Cookie Domain etc. We need to call “AddSession” method in ConfigureServices method of startup class. Microsoft.AspNetCore.Session package provides middleware to manage the sessions in ASP.NET Core.
This prevents the need to store a username and password in clear text within the configuration. When integrated authentication is used, ASP.NET accesses SQL Server using the credentials of the Windows user that the worker process runs as. By default, these credentials are ASPNET and NT AUTHORITY\NETWORK SERVICE on Windows Server 2003 running IIS 6.
The next line of code retrieves the stored value from the Session object. It then writes this value via the ‘Response.Write’ method back to the client. The other way is to use an object called a “Session Object.” The Session object is available throughout the lifecycle of the application.
The process is shared by multiple worker processes and web servers and servers as a memory-based database for holding session state data. StateServer serves data over a TCP port, typically port 42424, and allows incoming requests from outside servers. However, a drawback is that the usage of memory can grow over-time, potentially over-using the available server resources. Upon executing the web application, now a single magical spell is created and stored within session. Subsequent page refreshes continue to display the same magical spell and increment the view count each time. Since our web application is now loading session state from the 3rd-party StateServer process, all of the worker processes within the web garden can access the same, synchronized, session state data.