I have been looking to find a way for my Qt application to know if a VNC connection is active.
How/can I get a VNC connection status?
This is an embedded Linux application.
A starting point would be to look into the Qt sources at src/plugins/gfxdrivers/vnc/qscreenvnc_p.h; there a class QVNCServer is declared that also defines a isConnected() method which appears to do exactly what you need.
The crucial point, however, is to access that method from your application code; as can be deducted from the filename suffix _p the classes in that header are private (read: internal) to the Qt libs and not part of the public interface. Accordingly they are not documented in the reference, and I haven't found a public method to get the current QVNCServer object, nor any other VNC related instance that could provide a pointer to that object.
My suggestion is that you start with the related public interface in src/plugins/gfxdrivers/vnc/qscreenvnc_qws.h, which incorporates the server class as part of a QProxyScreen subclass, and work onwards from there to get an idea how the VNC server instance is created, and where the pointer to it is handled. You may be able to add a method to the QVNCScreen interface which allows you to get the connection state from your application. However you'll have to patch the Qt sources and rebuild the libraries.
Getting the QScreen object in application code is easy:
foreach(const QScreen* s, QScreen::instance()->subScreens())
{
if(s->classId() == QScreen::VNCClass)
//Here you can cast the screen instance and call a method on it
}
Related
With Liferay 6, using *LocalServiceUtil static calls was common. Starting from Liferay 7, these calls should be avoided in favor of #Referenceing the OSGi service and using it as a private member of the class, if I understood correctly (feel free to correct me).
Problem: When I replace my old *LocalServiceUtil calls with the OSGi-friendly equivalent, I get this exception:
com.liferay.portal.kernel.security.auth.PrincipalException:
PermissionChecker not initialized
at com.liferay.portal.kernel.service.BaseServiceImpl.getPermissionChecker
at com.liferay.portal.service.impl.UserServiceImpl.getUserById
How to fix it?
I could get a random admin via the OSGi equivalent of UserLocalServiceUtil.getRoleUsers(RoleLocalServiceUtil.getRole(company.getCompanyId(),"Administrator").getRoleId()) and use it in the the OSGi equivalent of PermissionThreadLocal.setPermissionChecker(PermissionCheckerFactoryUtil.create(randomAdmin)) but that sounds very hacky, plus it would put the responsibility of my code's actions on the shoulders of this unlucky admin.
My code:
protected void myMethod() {
userService.getUserById(userId);
}
#Reference(unbind = "-")
protected com.liferay.portal.kernel.service.UserService userService;
I think you actually wanted to inject UserLocalService.
In OSGi you should only strip the *Util suffix to receive equivalent functionality.
What you did is moved from LocalService (UserLocalServiceUtil) to remote service (UserService). The local services do not check permissions so there is no permission checker initialisation.
Apart from the above, you should be sure that no mischief can happen when using Local services. It's not recommended to expose this kind of functionality to end users but it's fine for some background processing.
I have a WebApp on Azure that uses a dll. This library needs Interop libraries x86 and x64.
Sometimes, at the restart of the App (I suppose), the App fails due to an exception:
System.EntryPointNotFoundException: Unable to find an entry point named 'sqlite3_config' in DLL 'SQLite.Interop.dll'. at System.Data.SQLite.UnsafeNativeMethods.sqlite3_config_none(SQLiteConfigOpsEnum op) at System.Data.SQLite.SQLite3.StaticIsInitialized() at System.Data.SQLite.SQLiteLog.Initialize() at System.Data.SQLite.SQLiteConnection..ctor(String connectionString, Boolean parseViaFramework) at T_Dox.WebService.SQLiteDb.CreateConnection() at WebService.CeDb.Connect()
The SQLite used is the SQLCipher's one.
What am I missing here? I don't understand why the app stops working suddenly even if I don't make any changes.
The App is a Web Service (.asmx file) that uses a data access layer to perform some business logic.
It was under a web site project, then we moved it into another project, a webapi\mvc project.
The routing bypasses this extension, so it works as before, a simple web service call.
The called web method initializes a business class loaded from another .net library (a VB.Net library).
Inside, this class uses a wrapper to a sqlConnection, in this case the SQLiteConnection.
In its constructor it starts an SQLiteConnection, and normally it works.
Then it performs some CRUD operations ...
So I can represent the operation this way:
[WebService(Namespace = "...")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class SampleService : System.Web.Services.WebService
{
[WebMethod]
public ServerInfo Test()
{
var sampleBusinessClass = new SampleBusinessCLass();
sampleBusinessClass.DoSomething();
using(var connection = new SQLiteConnection()) //the constructor is the parameterless one
{
//...
}
}
}
And the stack will be this (this is not the real one):
System.EntryPointNotFoundException: Unable to find an entry point named 'sqlite3_config' in DLL 'SQLite.Interop.dll'.
at System.Data.SQLite.UnsafeNativeMethods.sqlite3_config_none(SQLiteConfigOpsEnum op)
at System.Data.SQLite.SQLite3.StaticIsInitialized()
at System.Data.SQLite.SQLiteLog.Initialize()
at System.Data.SQLite.SQLiteConnection..ctor(String connectionString, Boolean parseViaFramework)
at xxx.WebService.SampleService.Test()
It always works, but sometimes it starts to launch this error until the stop and start of the web application on iss (in our case: Azure).
Inspecting the System.Data.SQlite.dll I can clearly see the entry point and actually it always passes this internal code (no conditions that can bypass this part) and it generally works.
The System.Data.SQlite.dll (1.0.96.0 version) is provided by SqlCypher product. I think it is the original System.Data.SQLite one because at first sight I can see the same assembly manifest and content.
The interop System.Data.SQLite uses is probably modified by SqlCypher team to give their features.
To avoid possible issues we put the interop in the path /bin/x64, then we compile our web app ONLY in x64 and it runs on a x64 environment.
when doing parallel/multithreading, if there are dependencies that are not thread safe, what kind of instance method can be used with autofac to get an instance per thread? from what I know, autofac is the kind of DI container for certain framework like asp.net/mvc but for the rest of the app type like windows service, it does not have any support. in my scenario, i am doing multithreading for a windows service that also hosting a web api service. what kind of registration can be used so that it will work for web api instanceperhttprequest and instanceperlifetimescope. two separate container?
EDIt:
using this parallel extension method here:
public static Task ForEachAsync<T>(this IEnumerable<T> source, int dop, Func<T, Task> body)
{
return Task.WhenAll(
from partition in Partitioner.Create(source).GetPartitions(dop)
select Task.Run(async delegate
{
using (partition)
{
while (partition.MoveNext())
{
await body(partition.Current);
}
}
}));
}
so the body will be use to do the work. DI will need to be inside of the body func.
It doesn't matter what kind of application you run; the pattern is always the same. You should resolve one object graph per request. In a web application, a request means a web request, in a windows service, a request is usually a timer pulse.
So in a windows service, each 'pulse' you start a new lifetime scope, and within this scope you resolve your root object and call it.
If however, you process items in parallel within a single request, you should see each processed item as a request of its own. So that means that on each thread you should start a new lifetime scope and resolve a sub object graph from that scope and execute that. Prevent passing services that are resolved from your container, from thread to thread. This scatters the knowledge of what is thread-safe, and what isn't throughout the application, instead of keeping that knowledge centralized in the startup path of your application where you compose your object graphs (the composition root).
Take a look at this article about working with dependency injection in multi-threaded applications. It's written for a different DI library, but you'll find most of the advice generically applicable to all DI libraries.
How do I configure my application so AutoMapper can map to internal types and/or properties in Silverlight 5? For example, I have the following type:
internal class SomeInfo
{
public String Value { get; set; }
}
I try to call Mapper.DynamicMap with this type as the destination and I receive the following error at runtime:
Attempt by security transparent method
'DynamicClass.SetValue(System.Object, System.Object)' to access
security critical type 'Acme.SomeInfo' failed.
I've tried instantiating the class first, then passing the instance to DynamicMap as well as changing the class scope to public with an internal setter for the property. I've also marked the class with the [SecuritySafeCritical] attribute. All of these tests resulted in the same error message.
The only way I've been able to get past this is to completely expose the class with public scope and public setters. This is, of course, a problem as I am developing a class library that will be used by other developers and using "internal" scope is a deliberate strategy to hide implementations details as well as make sure code is used only as intended (following the no public setters concept from DDD and CQRS).
That said, what can I do to make it so AutoMapper can work with internal types and/or properties?
(Note: The class library is built for SL5 and used in client apps configured to run out-of-browser with elevated trust.)
This is more of a Silverlight limitation - it does not allow reflection on private/protected/internal members from outside assemblies, see:
http://msdn.microsoft.com/en-us/library/stfy7tfc(VS.95).aspx
Simply put - AutoMapper can't access internal members of your assembly.
In a previous thread one of the respondents said that using wsHttpBinding used a session. Since I'm working in a clustered IIS environment, should I disable this? As far as I know, sessions don't work in a cluster.
If I need to disable this, how do I go about it?
That probably was me :-) By default, your service and the binding used will determine if a session comes into play or not.
If you don't do anything, and use wsHttpBinding, you'll have a session. If you want to avoid that, you should:
switch to another protocol/binding where appropriate
decorate your service contracts with a SessionMode attribute
If you want to stop a service from ever using a session, you can do so like this:
[ServiceContract(Namespace="....", SessionMode=SessionMode.NotAllowed)]
interface IYourSession
{
....
}
and you can decorate your service class with the appropriate instance context mode attributes:
[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]
class YourService : IYourService
{
....
}
With this, you should be pretty much on the safe side and not get any sessions whatsoever.
Marc