I am working with play framework 2.5. I know that there are certain events take place at the start of Play Application (netty server) such as class-loading, application loading, binding, injection etc.
But can anyone specify the general flow order when initializing and starting play application?
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I've been looking everywhere for some information as to how one might go about registering for power state changes in a C++ application. I don't have a window handle and the program does not always run in as a service. I see that there are powerstate broadcasts available to register for but I cant seem to find anyway to get to them. Any one have any idea?
Once I've received a power state change, I plan on informing all connected users to that machine.
I looking for some advice on the best way to set up a project. Not sure if this is the right place to ask but I will give it a go.
I am looking to create a "Smart Mirror". I know there are options already available for this but I want to go through the process of creating my own.
I have created the UI using electron and I am using this on a raspberry pi 3b+ using raspian stretch.
Now this is where my knowledge is lacking, due to no experience and not sure if what search terms to look for.
I would like to create a plug in on Chrome(used on my mobile phone) or a process that runs separately, to say "Send page/video to Smart Mirror". What I envisage is that this plug in will copy the URL for the page or the video and send this via a web service call. The running electron app on my raspberry pi will receive this call and process the URL and then display the page/video within a portion of the application.
I have only ever consumed a web service from within an application.
I am not sure how to set this up. Can my electron app be set up to receive this call? If so what search terms should I be looking for?
I hope this makes sense.
Please let me know your thoughts or if I am thinking about this all wrong
i am writing an program in c++ and i need an web interface to control the program and which will be efficient and best programming language ...
Your application will just have to listen to messages from the network that your web application would send to it.
Any web application (whatever the language) implementation could use sockets so don't worry about the details, just make sure your application manage messages that you made a protocol for.
Now, if you want to keep it all C++, you could use CPPCMS for your web application.
If it were Windows, I could advice you to register some COM component for your program. At least from ASP.NET it is easily accessible.
You could try some in-memory exchange techniques like reading/writing over a localhost socket connection. It however requires you to design some exchange protocol first.
Or data exchange via a database. You program writes/reads data from the database, the web front-end reads/writes data to the database.
You could use a framework like Thrift to communicate between a PHP/Python/Ruby/whatever webapp and a C++ daemon, or you could even go the extra mile (probably harder than just using something like Thrift) and write language bindings for the scripting language of your choice.
Either of the two options gives you the ability to write web-facing code in a language more suitable for the task while keeping the "heavy lifting" in C++.
Did you take a look at Wt? It's a widget-centric C++ framework for web applications, has a solid MVC system, an ORM, ...
The Win32 API method.
MSDN - Getting Started with Winsock:
http://msdn.microsoft.com/en-us/library/ms738545%28v=VS.85%29.aspx
(Since you didn't specify an OS, we're assuming Windows)
This is not as simple as it seems!
There is a mis-match between your C++ program (which presumibly is long running otherwise why would it need controlling) and a typical web program which starts up when it receives the http request and dies once the reply is sent.
You could possibly use one of the Java based web servers where it is possible to have a long running task.
Alternatively you could use a database or other storage as the communication medium:-
You program periodically writes it current status to a well know table, when a user invokes the control application it reads the current status and gives an appropriate set of options to the user which can then be stored in the DB, and actioned by your program the next time it polls for a request.
This works better if you have a queuing mechanism avaiable, as it can then be event driven rather than polled.
Go PHP :) Look at this Program execution Functions
I have a C++ Win32 application that was written as a Windows GUI project, and now I'm trying to figure out to make it into a Service / GUI hybrid. I understand that a Windows Service cannot / should not have a user interface. But allow me to explain what I have so far and what I'm shooting for.
WHAT I HAVE NOW is a windows application. When it is run it places an icon in the system tray that you can double-click on to open up the GUI. The purpose of this application is to process files located in a specified directory on a nightly schedule. The GUI consists of the following:
A button to start an unscheduled scan/process manually.
A button to open a dialog for modifying settings.
A List Box for displaying status messages sent from the processing thread.
A custom drawn window for displaying image data (the file processing includes the creation and saving of images).
A status bar - while a process is not running, it shows a countdown to the next scheduled scan. During a scan it also provides some status feedback, including a progress bar.
WHAT I'M SHOOTING FOR is a service that will run on boot-up and not require a user to login. This would consist of the scheduled file processing. However, when a user logs in I would still like the tray icon to be loaded and allow them to open up a GUI as I described above to monitor the current state of the service, change settings, start a scan manually, and monitor the progress of a scan.
I'm sure that I have seen applications like this - that function as a service even when I'm not logged in, but still give me a user interface to work with once I do log in.
I'm thinking that instead of having a single multi-threaded application that sends messages to the GUI thread from the processing thread, I need two applications - a Service to perform the processing and a GUI application to provide visual feedback from the Service and also send messages to the Service (for example, to start a scan manually). But I am new to Windows Services and have no idea how this is done.
It is also possible that I'm completely off base and a Service is not what I'm looking for at all.
Any help / ideas / suggestions would be greatly appreciated! Thank you.
You can't do this as a service.
You'll need to make your Windows Service as a normal service application. This will startup on system startup, and run the entire time the system is up.
You'd then make a completely separate GUI application, which "talks" to the service. This can be set to run when a user logs in, in the user's account.
In order to make them "talk" to each other, you'll need to use some form of IPC. Since these run on the same system (but in different accounts, typically), named pipes or sockets both work quite well.
There is a simple way of doing it.
You can’t have the service access any user’s session (session 1,2,3..) since services are isolated and can access session 0 only. This is a change from 2011.
You should write a win32 program to be launched by your service per each user who logs in using https://msdn.microsoft.com/en-us/library/windows/desktop/ms682429(v=vs.85).aspx
The service can continue performing any task that isn’t user specific.
I develop industrial client/server application (C++) with strong real time requirements.
I feel it is time to change the look of the client interface - which is developed in MFC - but I am wondering which would be the right choice.
If I go for a web client is there any way to exchange data between C++ and javascript other than AJAX <-> Web service <-> COM ?
Requirements for the web client are: Quick statuses refresh, user commands, tables
My team had to make that same decision a few months ago...
The cool thing about making it a web application would be that it would be very easy to modify later on. Even the user of the interface (with a little know-how) could modify it to suit his/her needs. Custom software becomes just that much easier.
We went with a web interface and ajax seems the way to go, it was quite responsive.
On the other hand, depending on how strong your real time requirements are, it might prove difficult. We had the challenge of plotting real time data through a browser, we ended up going with a firefox plugin to draw the plot. If you're simply trying to display real time text data, it shouldn't be as big an issue.
Run some tests for your specific application and see what it looks like.
Something else to consider, if you are having a web page be an interface to your server, keep in mind you will need to figure a way to update one client when another changes the state of the server if you plan on allowing multiple interfaces to your server.
I usually build my applications 2-folded :
Have the real heavy-duty application CLI-only. The protocol used is usually text-only based, composed of requests and answers.
Wrap a GUI around as another process that talks to the CLI back-end.
The web interface is then just another GUI to wrap around. It is also much easier to wrap a REST/JSON based API on the CLI interface (just automatically translate the messages).
The debugging is also quite easy to do, since you can just dump the requests between the 2 elements and reproduce the bugs much more easily.
Write an HTTP server in your server to handle the AJAX feedback. If you don't want to serve files, create your server on a non-standard port (eg. 8081) and use a regular web server for the actual web page delivery. Now have your AJAX engine communicate with the server on the Bizarro port instead of port 80.
But it's not that hard to write the file server part, also. If you do that, you also get to generate web pages on-the-fly with your data pre-filled, if you want.
Google Desktop Search does this now. When I search my desktop for 'foobar', the URL that opens is this:
http://127.0.0.1:4664/search?q=foobar&flags=68&num=10
In this case, the 4664 is the Bizarro port. (GoogleDesktop serves all the data here; it only uses the Bizarro port to avoid conflicts with any web server I might be running.)
You may want to consider where your data lives. If your application feeds a back-end database, you could write a web app leaving your c++ code in tact -- the web application would be independent and offer up pages to web users and talk directly to the database -- In this case you have as many options, and more, as you have indicated.