I create a connection using NSURLConnection in my view controller class. I want to make sure that my connections are nil when the AppDelegate calls the applicationWillResignActive methods.
I don't know how to call on that ivar from the AppDelegate. There is an answer on this site:
How to make variable accessible in the appDelegate and/or other view controllers?
This could work, but is there another way?
Thanks
Related
In a raw Spring WebSocket application (not using sockjs/STOMP or any other middleware), how can I have Spring inject beans that have been registered in the HTTP session scope so that they can be used by code in my WebSocketHandler bean?
Note that what I am not asking is any of these questions:
How do I create beans in a scope that is accessible to all handler invocations for the same WebSocket session (e.g. as described in the answer to Request or Session scope in Spring Websocket). The beans I need to access already exist in the scope for the HTTP session
How do I (programatically) access objects in the servlet container's HTTP session storage (I haven't tried to do this, but I'm pretty sure the answer involves using an HttpSessionHandshakeInterceptor), but that doesn't get me injection of Spring scoped dependencies.
How to use a ScopedProxy to pass beans between code in different scopes (e.g. as described here); I'm already familiar with how to do this, but attempting to do so for a WebSocketHandler causes an error because the session scope hasn't been bound to the thread at the point the object is accessed.
How to access the current security principal -- again, very useful, but not what I'm currently trying to achieve.
What I'm hoping to do is provide a simple framework that allows for the traditional HTTP-request initiated parts of an MVC application to communicate directly with a WebSocket protocol (for sending simple push updates to the client). What I want to be able to do is push data into a session scoped object from the MVC controller and pull it out in the websocket handler. I would like the simplest possible API for this from the MVC controller's perspective, which if it is possible to just use a session-scoped bean for this would be ideal. If you have any other ideas about very simple ways of sharing this data, I'd also like to hear those in case this approach isn't possible.
You can also use Java API for websocket. This link https://spring.io/blog/2013/05/23/spring-framework-4-0-m1-websocket-support
explains how to do this with Spring.
Ufortunately, something like this
#ServerEndpoint(value = "/sample", configurator = SpringConfigurator.class)
public class SampleEndpoint {
private SessionScopedBean sessionScopedBean;
#Autowired
public SampleEndpoint(SessionScopedBean sessionScopedBean) {
this.sessionScopedBean = sessionScopedBean;
}
}
causes exception (because we're trying to access bean outside its scope), but for singleton and prototype beans it works well.
To work with session attributes you can modify the hanshake and pass required attributes:
public class CustomWebSocketConfigurator extends SpringConfigurator {
#Override
public void modifyHandshake(ServerEndpointConfig config,
HandshakeRequest request,
HandshakeResponse response) {
//put attributes from http session to websocket session
HttpSession httpSession = (HttpSession) request.getHttpSession();
config.getUserProperties().put("some_attribute",
httpSession.getAttribute("some_attribute_in_http_session"));
}
}
P. S. More a comment than an answer. I just wanted to add another way of handling session attributes in websocket to your question-answer. I have been searching the web for exactly the same issue and the way showed above seems to me the most systematic approach to handling the session data in websocket.
How come the method called from Client-side has to be a static method? The issue i am facing is that if the method is static then I can't access my server side controls such as CheckBoxPanel.
Is there any workaround this?
The method is static so that the server doesn't need to create an instance of the Page class just to run the method.
Even if the method wasn't static, you wouldn't be able to use the controls in the page anyway, because the form data in the page isn't posted to the server when you make a PageMethod call. You need to send all the information that the method needs in the call itself.
Background
I have a multitenant application that uses multiple databases per-tenant. I'm using CodeFirstMembership, so I have full controll over the SimpleMembership implementation. Both my User/Role entities are in the same DbContext as the rest of my application.
The Problem
In order to facilitate multi-tenance, I have a custom route that looks exactly the same as what the default vanilla MVC route looks like, with the exception that I grab the subdomain, check it against the tenants that have an account, and grab their specific connection string. I have an extension method on the RouteData called .GetSubdomain() that will return the subdomain used, so I can really do the check and get the connection string wherever, if that helps you with your answer.
I need my membership provider to be able to access the subdomain check information in order to point to the correct database for the [Authorize] method to work correctly.
What I've tried
Initializing the membership provider in the InitializeSimpleMembershipAttribute
This didn't work because you can't pass in dynamic parameters into attributes (like RouteData.GetSubdomain())
Initializing the membership in the constructor.
While you can call RouteData methods in the constructor and have the app build/run, RouteData has not been populated at the point of the constructor in a controller, so this method didn't work either.
I didn't try this, but adding the check at the start of each controller method is likely not to work since the authorization has already ran.
So...
Out of what I've tried, it seems like I need to hook into the point between where RouteData is populated and the actual Authorization. Is there a point I can do this effectively?
Thanks!
WOW. In a total oversight, I failed to see the ActionExecutingContext that was being passed into the InitializeSimpleMembership attribute. The context being passed in actually contains RouteData, and the subdomain information needed to properly initialize the membership!
Ive got a WCF service which has multiple web methods in it. I want to be able to intercept the request on all methods and look at the Ip address. Id rather not put the logic into a method call at the top of each called web method is there a way to intercept all calls to these methods from one place?
If it was a page I would write a base page object but im nout sure if there are events raised on a wcf call?
WCF allows you to implement interceptors that are added to the stack. See this link for an example. I´m not sure whether this allows you the extract the senders IP but I think it´s worth a try.
You can implement IDispatchMessageInspector and do something like this.
public object AfterReceiveRequest(ref Message request,
IClientChannel channel, InstanceContext instanceContext)
{
RemoteEndpointMessageProperty remoteEndpoint = request.Properties
[RemoteEndpointMessageProperty.Name] as RemoteEndpointMessageProperty;
//remoteEndpoint.Address will give you the address.
return null;
}
You can use Custom Behaviors, they are part of WCF Extensibility features. Here's more information: Extending WCF with Custom Behaviors
There's a clever way to do this with the ServiceAuthorizationManager, and it's far easier than all the seriously hard work of the IDispatchMessageInspector.
Create a class in your WCF Service project like so:
public class MyServiceAuthorizationManager : ServiceAuthorizationManager
{
protected override bool CheckAccessCore(OperationContext operationContext)
{
string classMethod = operationContext.RequestContext.RequestMessage.Headers.Action;
if (classMethod.Contains("/transfer/Get"))
{
return true; // because someone is simply updating a client service reference
}
Console.WriteLine("Class Method Call: {0}",classMethod);
// do something with operationContext here as you need to inspect stuff
// return true if you want this class method call to succeed and go through
// return false if you want this class method to fail on the client
return true;
}
}
Then, in your service, right before your host.Open() call, add the link to MyServiceAuthorizationManager.
ServiceHost host = new ServiceHost(typeof(MyProject.Service1));
host.Authorization.ServiceAuthorizationManager = new MyServiceAuthorizationManager();
host.Open();
Now when you test your client connections, you'll notice that the console outputs what class method was called. You can also work against all the stuff in the operationContext object.
One way I use this is for a security header check. In my client, I add a header. Then, in the service, in this CheckAccessCore() call, I verify that this custom header exists. If it doesn't, then I return false. This is one more layer of protection that keeps the hackers out, and is great for the limited security in Named Pipes configurations too. If you're wanting to also do that, then click here for more information on how to add custom headers that automatically get sent on every client's method call on the service.
And note, among all this, I didn't have to mess with behaviors, claims, listeners, or message dispatches. I also didn't need to edit my WCF Configuration.
Note the string check for /transfer/Get above. This is important if you're doing header checks as a security mechanism like I was. If you don't have that condition and return true, then your WCF client IDE can't update its ServiceReference because the IDE doesn't know about that extra header (if you're adding a custom header and not specifying that header in the WCF client's app.config). Otherwise, you'll get an error The URI prefix is not recognized.
From client side, I need to call a server method that is not static.
For example, I got the following user control ucData (private instance of code-behind) that is Databind in the load event.
The server method I need should return ucData.IsValid(). So it can't be static
Is there a way I can do that ?
No...because there is no instance on the server to call the method on. Once the page is generated and sent to the client, there is no more context and all instances are destroyed.
Your best option is going to be to:
Create a static method
Pass that method the info needed to create the instance of the object you need
Call the method on the instance you just created
Return the results from your static method.