Session variable are set to null between page - asp.net

I have a solution with 2 projects : Core and Web. In the Core, I manage session I do something and I call this method :
public void SetLog()
{
HttpContext.Current.Session["Logged"] = true;
}
That's work.
When I change page (I use the ASP.NET 4.0 default template for testing), I click on the "About" link and I call this method :
public bool IsLogged()
{
if (HttpContext.Current.Session["Logged"] == null)
return false;
return true;
}
On the About page, Session are null, normal ? how solve this ?
Thanks,

I suspect that you have 2 web applications: Core and Web hosted on 2 different domains: http://localhost:1234 and http://localhost:5678. You seem to be setting the session variable inside the first web application but this session is only about the first application. As soon as you leave this application the other has a completely distinct session. Remember that sessions cannot be shared between ASP.NET applications. There are workarounds for this but out of the box it doesn't work.

Related

Implementing Security in ASP.NET Web App as afterthought

As with many real world applications out there, the security (login/password) was just there to grant/deny access to the complete application. Now the client has asked for fine grained security like some web pages should only be viewable, some users can delete other cannot etc.
basically the client is requesting the following.
Effective Permission:: Users--> Web page --> Type of Access (View,Create/Edit,Delete)
Details of Application
ASP.NET/C#
MSSQL Server 2008 for Biz data
SQLCE for users/passwords/profiles/logs
Ext.NET for main UI
We discussed that it is better to enhance the security.sdf file and have a table for screens (webpages) and a join table of user + screens + a number that denotes type of access i.e.
1: Read
2: Write
4: Delete
These can be checked using bitwise operator. The application uses ASP.NET impersonation to gain access to MSSQL2008
The problem is how to implement it in the web application?
If anyone has better ideas please share!!!
You can use the IsInRole function and categorize your users into roles. Each role can have some action that can be done only. So by asking in witch role is the user you can let him do or not thinks.
HttpContext.Current.User.IsInRole("Role")
Or you can do it reversely, ask if this action is available for this role, here is a simple object, with permissions and checks.
public enum csPermissions
{
pActionDelete = 1,
pActionEdit = 2 ,
// more names...
}
private int[] AdminPermission = {
(int)csPermissions.pActionEdit,
(int)csPermissions.pActionDelete,
// more permissions...
};
private int[] BackOfficePermission = {
(int)csPermissions.pActionEdit,
// more permissions...
};
public static bool IsThisAllowed(csPermissions AskPermitForThisAction)
{
// questions here for all users roles...
// here is only an example
if (HttpContext.Current.User.IsInRole("Administator")))
{
for (int i = 0; i < AdminPermission.Length; i++)
if (AdminPermission[i] == (int)AskPermitForThisAction)
return true;
}
// no permission found
return false;
}

Read AssemblyTitle attribute in ASP.NET

I use code below to read AssemblyTitle attribute of .NET apps, unfortunately Assembly.GetEntryAssembly() always return Null in ASP.NET app. How to read AssemblyTitle in ASP.NET app?
public static string Title
{
get
{
var attributes = Assembly.GetEntryAssembly().GetCustomAttributes(typeof(AssemblyTitleAttribute), false);
if (attributes.Length > 0)
{
var titleAttribute = (AssemblyTitleAttribute)attributes[0];
if (titleAttribute.Title.Length > 0)
return titleAttribute.Title;
}
return System.IO.Path.GetFileNameWithoutExtension(Assembly.GetEntryAssembly().CodeBase);
}
}
You must have a type that you know is defined in the same assembly that contains the AssemblyTitle. Then you can do:
typeof(MyType).Assembly.GetCustomAttributes
Note that (for what I know) there isn't any other bulletproof method.
For example using HttpContext.Current doesn't work if you want to do it not during a web request (so you can do it on response of a user action, but not from a separate thread, or from a static initializer, or from global.asax)
Some similar readings (full of half successes):
GetEntryAssembly for web applications
Using the Web Application version number from an assembly (ASP.NET/C#)
I use the following in asp.net web app:
if (ApplicationDeployment.IsNetworkDeployed)
return ApplicationDeployment.CurrentDeployment.CurrentVersion.ToString();
return System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString();
Edit: Sorry, thats just the version, not the title! I combined your version and mine:
System.Reflection.Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(AssemblyTitleAttribute), false);
That gets the assembly title attribute just fine. The difference is in GetExecutingAssembly() versus your GetEntryAssembly().

How to prevent user from direct url entering

I am using ASP.NET 4.0 Framework.I have a directory which contains 10 PDF files i.e pdf1,pdf2....pdf10. On button click i am using Response.Redirect & passing Pdf file path in order to open it in the browser. but, this enables user to view the path(url) of the PDF folder using this url he can open any other pdf directly. How can i stop him accessing PDF directly from the url
Use Request.ServerVariables["HTTP_REFERER"] this will tell you where the request had come from. If its not on your site then take appropriate action.
e.g.
if(Request.ServerVariables["HTTP_REFERER"].ToLower().IndexOf("mysite.com") == -1){
// Not from my site
Response.Redirect("NotAllowed.aspx");
}
This link may help you to stop him accessing PDF directly from the url.
Use this code in Global.asax.cs and Call [NoDirectAccess] to all controllers
//Prevent direct URL access: Call [NoDirectAccess] to all controllers to block
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class NoDirectAccessAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (filterContext.HttpContext.Request.UrlReferrer == null ||
filterContext.HttpContext.Request.Url.Host != filterContext.HttpContext.Request.UrlReferrer.Host)
{
filterContext.Result = new RedirectToRouteResult(new
RouteValueDictionary(new { controller = "Home", action = "Login", area = "" }));
}
}
}
You will need to add a secure layer. If you are using MVC it will probably be simpler to implement since you will do the authorisation in the controller action. However, for classic ASP you will probably need to implement a custom handler.
There is no easy solution to this. You could devise some sort of rolling code based on the server date/time that must be part of the query string and check for the correctness of this in the page load, if you make it sufficiently complicated / long, then people will not be able to enter this manually.

How to get HealthVault to work with multiple ApplicationID in same application

We may never know why Microsoft decided to limit developers by making HealthVault applications constrained to a single web/app.config entry for a HealthVault application. However I need to be able to make 2 (or more) HealthVault ApplicationID’s work with one ASP.NET website? I’m looking for an effective and reliable way to do this.
I won’t go into the details of the reasoning behind 2 different HealthVault applications, but other than to say we need it to work. I still cannot login correctly with MSDN Forums (think infinite redirection sign in loop) so I am hoping for a post here that will help me.
I did contact a HealthVault developer on how to achieve this however the developer gave a suggestion that I don’t believe would be reliable (if I’m wrong let me know).
The developer’s suggestion was to do the following in code when you needed to connect to HealthVault, but prior to connecting:
ConfigurationSettings.AppSettings[“ApplicationId”] = “[YOUR APP ID]”;
The problem is that this is a static property and I do see this as an issue as our web application will have different users accessing both HealthVault applications at the same time.
Does anyone have any suggestions to make 2 (or more) HealthVault ApplicationID’s work with one ASP.NET website? I’m looking for an effective and reliable way to do this.
There is a way to dynamically switch app ids on runtime. Both applications must be created, both certificates must be installed. Few things to keep in mind. For every authenticated connection, user will be granted a token (aka wctoken). This token is consumed when user is redirect back from Live ID (in case live id is used...) by your redirect.aspx page (assuming your redirect page inherits from HealthServiceActionPage.This means that everytime you switch applications, you must redirect user back to Live ID with new app id to receive new token.
Here is code sample that can be user to dynamically change settings:
public class ConfigurationManager : HealthWebApplicationConfiguration
{
private string appid;
public ConfigurationManager(string appid)
{
this.appid = appid;
}
public override Guid ApplicationId
{
get
{
return AppManager.Current.GetCurrentAppId(this.appid);
}
}
}
public class AppManager
{
private static readonly Object lck = new Object();
public Guid? App;
public static AppManager Current
{
get
{
AppManager mgr = null;
if (_current == null)
{
lock (lck)
{
mgr = new AppManager();
}
}
return mgr;
}
}
private static AppManager _current;
public Guid GetCurrentAppId(string id)
{
return new Guid(id);
}
}
Usage:
ConfigurationManager cm = new ConfigurationManager(your-app-id-here);
HealthWebApplicationConfiguration.Current = cm;

Static variables and long running thread on IIS 7.5

Help me solve next problem.
I have ASP .NET MVC2 application. I run it on IIS 7.5. In one page user clicks button and handler for this button sends request to server (jquery.ajax). At server action in controller starts new thread (it makes long time import):
var thread = new Thread(RefreshCitiesInDatabase);
thread.Start();
State of import is available in static variable. New thread changes value of variable in the begin of work.
User can check state of import too with the help of this variable, which is used in view. And user sees import's state.
When I start this function few minutes everything is okey. On page I see right state of import, quantity of imported records is changed, I see changes in logs. But after few minutes begin troubles.
When I refresh page with import state sometimes I see that import is okey but sometimes I see page with default values about import (like application is just started), but after that again I can see page with normal import's state.
I tried to attach Visual Studio to IIS process and debug application. But when request comes to controller sometimes static variables have right values and sometimes they have default values (static int has 0, static string has "" etc.).
Tell me what I do wrong. May be I must start additional thread in other way?
Thanks in advance,
Dmitry
I add parts of code:
Controller:
public class ImportCitiesController : Controller
{
[Dependency]
public SaveCities SaveCities { get; set; }
//Start import
public JsonResult StartCitiesImport()
{
//Methos in core dll, which makes import
SaveCities.StartCitiesSaving();
return Json("ok");
}
//Get Information about import
public ActionResult GetImportState()
{
var model = new ImportCityStatusModel
{ NowImportProcessing = SaveCities.CitiesSaving };
return View(model);
}
}
Class in Core:
public class SaveCities
{
// Property equals true, when program are saving to database
public static bool CitiesSaving = false;
public void StartCitiesSaving()
{
var thread = new Thread(RefreshCitiesInDatabase);
thread.Start();
}
private static void RefreshCitiesInDatabase()
{
CitiesSaving = true;
//Processing......
CitiesSaving = false;
}
}
UPDATE
I think, I found problem, but still I don't know how solve it. My IIS uses application pool with parameter "Maximum Worker Processes" = 10. And all tasks in application are handled by few processes. And my request to controll about import's state always is handled by different processes. And they have different static variables. I guess it is right way for solving.
But I don't know how merge all static values in one place.
Without looking at the code, here are the obvious question. Are you sure your access is thread safe (that is do you properly use lock to update you value or even access it => C# thread safety with get/set) ?
A code sample could be nice.
thanks for the code, it seem that CitiesSaving is not locked properly before read/write you should hide the instance variable behind a property to handle all the locking. Marking this field as volatile could also help (see http://msdn.microsoft.com/en-us/library/aa645755(v=vs.71).aspx )

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