I'm putting together a very basic sort of "hello world" app with SignalR, with the minor caveat that it's self-hosted, which introduces an additional wrinkle or two. Basically, I'm trying to figure out the right way to call methods on my client(s) from the server.
On my client, for instance, I've got a method that looks like this:
roomHub.onEcho = function (msg) {
console.log("onEcho called: " + msg);
};
And I can call it successfully from my server-side hub like so:
public class RoomHub : Hub
{
public void Echo(string echo)
{
Clients.onEcho(echo);
}
}
And it works, but of course, it calls all the clients, not just one. And in the various samples I've seen online (e.g., https://github.com/SignalR/SignalR/blob/master/samples/Microsoft.AspNet.SignalR.Hosting.AspNet.Samples/Hubs/Benchmark/HubBench.cs, I see all sorts of commands that make it look like I should be able to specify who gets called, e.g.:
public void Echo(string echo)
{
Clients.Caller.onEcho(echo);
Clients.Caller(Context.ConnectionId).onEcho(echo);
Clients.All.onEcho(echo);
}
But I can't get any of the above syntaxes to work. For Clients.All.onEcho() and Clients.Caller.onEcho(), absolutely nothing happens. For Clients.Caller(Context.ConnectionId).onEcho(), Firebug tells me that it's actually trying to call a Caller() method on my JavaScript roomHub instance, which of course isn't there.
Here's the weird bit, though. If I look at the Hub class, I can see why none of these work - because the Hub constructor overrides a bunch of the properties of its "Clients" object with NullClientProxies:
protected Hub()
{
Clients = new HubConnectionContext();
Clients.All = new NullClientProxy();
Clients.Others = new NullClientProxy();
Clients.Caller = new NullClientProxy();
}
But I'm kinda mystified as to why it does that - or why the samples seem to work anyway - or what the expected approach should be.
Any thoughts? What am I doing wrong here?
We've been updating docs recently so you've probably seen lots of inconsistent data around the place. The latest version of SignalR is 1.0 alpha2 ( http://weblogs.asp.net/davidfowler/archive/2012/11/11/microsoft-asp-net-signalr.aspx ). All of the documentation has been updated to show the new syntax so if you're using an older version, please upgrade. Check out the wiki for examples https://github.com/SignalR/SignalR/wiki/Hubs
Related
Let's say I have these classes:
Old_Class
New_Class
If this exists ->something(new Old_Class()) or Old_Class::staticMethod() or $oldClass->methodCall() I want a code sniff to warn "Old_Class usage found, recommend using New_Class instead".
I found this sniff Generic.PHP.ForbiddenFunctions but it only seems to catch built-in php functions is_array, is_null, etc.
Do I need to write a custom sniff for this?
If so, what token should I added to the register() function to catch on?
I couldn't use a built-in one. I had to write one using T_STRING.
public function register()
{
return [
T_STRING,
];
}
public function process(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
{
$tokens = $phpcsFile->getTokens();
if ($tokens[$stackPtr]['content'] === 'Old_Class') {
$error = 'Old_Class usage found, consider using New_Class instead.';
$phpcsFile->addWarning($error, $stackPtr);
}
}
I know this is a fairly old question, but there are two possible solutions I'm aware of:
The Slevomat coding standard for Codesniffer includes a sniff to report usage of any of an array of forbidden classes
Static analysis tools are another approach for this. If you mark a class with the #deprecated annotation, I know from personal experience that Psalm will flag it with the DeprecatedClass issue, and if you can't fix them all at once, you can add them to the baseline, which will suppress the issue, but keep track of it, so you can still use Psalm in continuous integration and not break on existing issues. I believe PHPStan has similar functionality.
I suspect a problem with an old version of the ObjectBuilder which once was part of the WCSF Extension project and meanwhile moved into Unity. I am not sure whether I am on the right way or not so I hope someone out there has more competent thread-safety skills to explain whether this could be an issue or not.
I use this (outdated) ObjectBuilder implementation in an ASP.Net WCSF web app and rarely I can see in the logs that the ObjectBuilder is complaining that a particular property of a class cannot be injected for some reason, the problem is always that this property should never been injected at all. Property and class are changing constantly. I traced the code down to a method where a dictionary is used to hold the information whether a property is handled by the ObjectBuilder or not.
My question basically comes down to: Is there a thread-safety issue in the following code which could cause the ObjectBuilder to get inconsistent data from its dictionary?
The class which holds this code (ReflectionStrategy.cs) is created as Singleton, so all requests to my web application use this class to create its view/page objects. Its dictionary is a private field, only used in this method and declared like that:
private Dictionary<int, bool> _memberRequiresProcessingCache = new Dictionary<int, bool>();
private bool InnerMemberRequiresProcessing(IReflectionMemberInfo<TMemberInfo> member)
{
bool requires;
lock (_readLockerMrp)
{
if (!_memberRequiresProcessingCache.TryGetValue(member.MemberInfo.GetHashCode(), out requires))
{
lock (_writeLockerMrp)
{
if (!_memberRequiresProcessingCache.TryGetValue(member.MemberInfo.GetHashCode(), out requires))
{
requires = MemberRequiresProcessing(member);
_memberRequiresProcessingCache.Add(member.MemberInfo.GetHashCode(), requires);
}
}
}
}
return requires;
}
This code above is not the latest version you can find on Codeplex but I still want to know whether it might be the cause of my ObjectBuilder exceptions. While we speak I work on an update to get this old code replaced by the latest version. This is the latest implementation, unfortunately I cannot find any information why it has been changed. Might be for a bug, might be for performance...
private bool InnerMemberRequiresProcessing(IReflectionMemberInfo<TMemberInfo> member)
{
bool requires;
if (!_memberRequiresProcessingCache.TryGetValue(member.MemberInfo, out requires))
{
lock (_writeLockerMrp)
{
if (!_memberRequiresProcessingCache.TryGetValue(member.MemberInfo, out requires))
{
Dictionary<TMemberInfo, bool> tempMemberRequiresProcessingCache =
new Dictionary<TMemberInfo, bool>(_memberRequiresProcessingCache);
requires = MemberRequiresProcessing(member);
tempMemberRequiresProcessingCache.Add(member.MemberInfo, requires);
_memberRequiresProcessingCache = tempMemberRequiresProcessingCache;
}
}
}
return requires;
}
The use of the hash code looks problematic if you run a very large number of classes / members, as can happen with the singleton approach you mentioned.
The double lock was totally odd in the old one (Only one thread goes into the whole section in all cases). Note that locking as the first thing certainly hurts performance. It is a trade of, notice that instead they create a copy to avoid modifying the list as it is being read.
in Flex 3.2 Having troubles converting remote object result to specific object on client side in modules.
For example I have VIPSAdmin module.
it has function
private function doResult(event:ResultEvent):void {
var data_:Array = ArrayUtil.toArray(event.result);
var result:ResultDTO = data_[0] as ResultDTO;
if(!result.isError()) {
trace(result.result);
vipsAdminDTO = result.result as VIPSAdmin;
compId= vipsAdminDTO.compId; // second time dying here
}
}
Function invoked when I get data from remote objet.
First time all great,when I unload this modeule and load it again:
data_[0] as ResultDTO;
Performs fine, but
vipsAdminDTO = result.result as VIPSAdmin;
vipsAdminDTO always null!
Even when
trace(result.result);
produces [object VIPSAdmin]
What a heck I missing here!? Looks like it just cannot do
result.result as VIPSAdmin;
even when trace and debug says it is instance of VIPSAdmin
I've figured out what is the problem, problem is that when I first instantiate something in module then in main app, somehow classes are not alined even that they are identical !
So solution is to make a fake instance in application class first, then if you use that same class to make an instance in module it will work!
I do it very simple in my main application class I just added:
VIPSAdmin;
This seems to create some sort of ghost instance, which I belie will be pickup by GC later, but will build tables of instances properly! Which solved my problem.
Not sure if this is appropriate solution ! but it sure works.
I am developing an application in GWT as my Bachelor's Thesis and I am fairly new to this. I have researched asynchronous callbacks on the internet. What I want to do is this: I want to handle the login of a user and display different data if they are an admin or a plain user.
My call looks like this:
serverCall.isAdmin(new AsyncCallback<Boolean>() {
public void onFailure(Throwable caught) {
//display error
}
public void onSuccess(Boolean admin) {
if (!admin){
//do something
}
else{
//do something else
}
}
});
Now, the code examples I have seen handle the data in the //do something// part directly. We discussed this with the person who is supervising me and I had the idea that I could fire an event upon success and when this event is fired load the page accordingly. Is this a good idea? Or should I stick with loading everything in the inner function? What confuses me about async callbacks is the fact that I can only use final variables inside the onSuccess function so I would rather not handle things in there - insight would be appreciated.
Thanks!
Since the inner-class/ anonymous function it is generated at runtime it needs a static memory reference to the variables it accesses. Putting final to a variable makes its memory address static, putting it to a safe memory region. The same happens if you reference a class field.
Its just standard java why you can only use Final variables inside an inner-class. Here is a great discussion discussing this topic.
When I use the AsyncCallback I do exactly what you suggested, I fire an event though GWT's EventBus. This allows several different parts of my application to respond when a user does log in.
When I'm in the flash debugger, and I have some callbacks saved, I can see that the functions have a property named savedThis that is very usefull to know where that callback came from.
I'm trying to access that property from code, but for some reason I can't.
callback.savedThis throws an Error because it can't find the property, probable because it's private.
So I tried to add a method to the Function class that would give me access to it:
Function.prototype.getSavedThis = function()
{
return this.savedThis
}
But it gives me the same error about not finding the property, even though I can see it in the debugger.
Is there a way to access it?
Note: I'm not planing on using this in production code, I'm making some classes to help me with debugging by automating some data gathering, and it would be incredible useful to get this information without having to add code to every callback saved informing of the this object.
You can get a reference to a calling function by using the 'arguments.callee' property.
For example:
bar( arguments.callee );
public function bar( caller:Function ) : void { trace( caller ); }