I'm using reactive extensions (well, trying, learning) in a windows store app. I have a series of async operations that will eventually navigate to an authorization web page for RTM. Given the reading I've done, I would expect to write something like the following:
var result = rtm
.GetFrob()
.Select(s => rtm.GetAuthenticationUrl(s))
.ObserveOnDispatcher()
.Do(uri => AuthWebView.Navigate(new Uri(uri)))
.First();
However, I can't seem to find a method ObserveOnDispatcher, and further there is no Scheduler.Dispatcher property either, leading me to think on a Windows Store application there is something deeper gong on with the main UI thread and how you reference it.
GetFrob, btw, creates an IObservable sequence using Observable.FromAsync (if that helps with this).
BTW, if I remove that line, I fail in the call to the Navigate as posting it from the wrong thread. So, what is the proper thing to do here to make sure I'm back on the correct thread?
BTW, Excuse the ".Do" operation here, I know it isn't "nice", however, I'm still experimenting in throw-away code.
Many thanks in advance!
Argh. Apparently I just am not good enough at search. :(
Turns out that adding the nuget package Rx-Xaml includes the proper assemblies for the scheduler, etc. Details can be found on the main Rx blog. Of course, my app is back to hanging now, but that may be due to something else dumb on my part.
Related
I'm new to the world of coding and Web dev and for my first real project, I've started building a quiz web app using Meteor.
Long story short, the app basically displays a random question to the user, then takes in their answer and gets feedback (it's a bit more complicated than that, but for the purposes of this question, that's the main functionality).
I've managed to get it working, but pretty much everything (apart from account creation and that kind of stuff) is done on the client-side (such as getting the random qn) - which I'd imagine is not very secure..
I'd like to move most of the calculations and operations on the server, but I don't want to publish any of the Questions collection to the client, since that means the client can essentially change it and/or view the correct answer.
So, my question is, would it be considered 'bad practice' if I don't publish anything to the client (except their user document) and basically do everything through Meteor methods (called on the client, and executed server-side)?
I've already tried implementing it and so far everything's working fine, but was just wondering whether it's good practice. Would it hurt performance in any way?
I've searched online for a while, but couldn't really find a definitive answer, hence my post here... TIA
The below example pulled right from the documentation showing how to omit fields.
// Server: Publish the `Rooms` collection, minus secret info...
Meteor.publish('rooms', function () {
return Rooms.find({}, {
fields: { secretInfo: 0 }
});
});
Hint: this one might sound complicated, because I am trying to give as much info as possible, but I suspect that I just want someone to tell me "yes, you are correct".
On this legacy system, which dates from 2002, the user visits a web page and uses an RFID reader to read a tag number, which is then written to an input field on the web page.
The only s/w that comes with the reader is a custom DLL, nop .exe.
The very sparse documentation insists that only MSIE be used and that all security relating to ActiveX be disabled.
When I look into the source of the web page I see calls to functions in the DLL.
Now, here's the fun part: I know zilch about ActiveX, I have to make a minor change to the DLL *but* the VB6 source code has been lost, so I guess that I have to recreate the (seemingly very simple) DLL from scratch - this week.
Decompiling the DLL shows me the functions (locateReader, getTagVal, closeReader). However, by decompiling I can't really know the number or type of the parameters, nor the return values ... and if anyone knows the API they are refusing to share it, but basically it all seems to have been lost in the mists of time as companies went bust, were bought & sold, merged & demerged and the initial DLL might have been written by an external guy, but no one knows who.
So, can I get the function params & type from the ASP page source?
I see things like
Reader = new ActiveXObject("<dllName>.Reader");
Reader.locateReader();
tagVal = Reader.getTagVal();
Reader.closeReader();
So, I would say that none of the fn()s take parameters, that closeReader doesn't have to return anything; it looks like locateReader doesn't return anything either, so I guess that error handling will have to be in the DLL (loop forever with a popup demanding that a reader be attached; and getTagVal seems to return a string.
Does that sound about right? Any other comments (other than lessons to be learned)?
The 'code' you've put here looks like the a direct call to the device. And getTagVal() seems to get the RFID value? Since this is an COM (Active X) call can you call this in a simple .net program and see if you can access the reader? If you can then you may be able to just wrap the existing functionaliy in your wrapper.
You need to try and generate a TLB from the component:
So, if you only have a COM dll, you
need to get an idl-file from it:
Visual Studio, start it and go to the meny Tools->OLE/COM Object Viewer.
This is called oleview.exe and can also be got from the windows sdk
In that application, select meny File->View Typelib..
Select the COM dll and you will see the Typelib.
Select the meny File->Save as. Save it with an appropriate name. For
example "mycom.idl"
start midl.exe or mktyplib.exe with the idl-filname as the argument. "midl
mycom.idl"
Read MSDN for more info about midl and
mktyplib
Are the any GIL-less LLVM-based languages, targeted mainly for JIT-execution which allows to reload PART of the code on the fly?
Like re-compile 1 class, and reload it without stopping the whole program.
Anyone tryed that?
Any chance on doing that with clang (surely, with great deal of developers caution, restriction and manual state handling)?
I think that this is a dynamite idea, and a feature that I would love to have! Have you given any thought to how you would like to interface with the feature?
obj1 = Foo()
compiler.Recompile(Foo, '/some/path/myapp/newsrc/foo.blah');
obj2 = Foo()
// Would this be True?
type(obj1) == type(obj2)
I assume that you expect existing instances to remain unchanged by the recompile?
This seems like it would be easier with functions, as long as they kept the same prototype, but doing it with classes seems like it would get messy.
Also, what to do about threading?
Thread.start(wait 1; bar();); // bar is a function
compiler.Recompile(bar, '/some/path/myapp/newsrc/bar.blah');
Lets say that in our thread we start calling "bar" during the recompile. Does the call block until the recompile is done and then call the new function? Does the old function still exist until the compile is complete? What if we have a function pointer, after the recompile, where does it point? To the original function or to the new one?
Does anyone have any thoughts on how this could be implemented in a strait forward way?
Hmm, can't think of anything off the top of my head. The only major product I can think of is JRebel, but that's for Java.
Apparently, it does not exist yet.
I've asked this before but I was hoping for another answer and perhaps some code samples because I've been having a difficult time with this. I have an asp.net page. The user hits the "Run" button and I have code IN AN ASSEMBLY, not in the APP_CODE folder that is called and runs a long process that moves product info from a file into the database. While the user waits, I would like them to see status updates like what product the import process in on and status info. I'm assuming I'd break off into another thread and use Ajax but I have no idea how to do this. Some code samples would be very helpful, thanks.
A simpler way to do this without needing to go into multi threading (which can cause all sorts of nasty, hard to track down bugs) is to use AsyncResults in .NET and AJAX which allow you to query a process.
A good example to start you off can be found here.
found it by using HttpResponse.Flush
I have seen several projects that use the Trace functionality to capture events and stream them out to a log file. I have been unsuccessful in finding a simple to follow guide that will show me how to configure Trace to capture and write said logfile. Does anyone have a link recommendations, or provide some simple steps to follow?
The Trace object writes the statements to any attached TraceListeners. You can build your own, but there are a number already defined in the System.Diagnostics namespace, including:
ConsoleTraceListener (Console)
DefaultTraceListener (Visual Studio / Debugger)
DelimitedListTraceListener (TextWriter, special formatting)
EventLogTraceListener (EventLog - anything that inherits from System.Diagnostics.EventLog)
TextWriterTraceListener (TextWriter - think file)
You can, of course, inherit your own from the TraceListener class that writes to where ever you want. For example, you could log to a database, have it send e-mails or pages in certain situations, or write the statements back to a logging platform like log4net.
The big thing is that you need to create an instance of whatever listeners you want and then add them to the Trace' class Listeners collection. You can add as many as you need and Trace will write to all of them. This way, you can write your logging code once using a well-supported and understood object that's part of the framework, and you can attach anything you need to it.
I stumbled into a MSDN article that really helps. Sorry I didn't find it before posting the question but perhaps others may have the same question and haven't found this link.
Take a look at logging frameworks. We rolled out own, but are now migrating over to log4net available free at http://logging.apache.org/log4net/
Im looking for a way to set the Category of the EventLog, the FormattedEventLogTraceListener writes into (not the category of the message).
But I can't find an appropriate property of this class.
Is it possible to set this?