I have a qt main-window application from which several dialogs are accessed.
I implemented the server and client versions of the application using tcp/ip using c socket programming.
But now I have been told to make the application accessible to any web browser after username and password have been given using QHttp or any appropriate class.
I'm a beginner and have no idea of implementing this. Could anyone give some tips or examples.
I'm using qt 4.6.2
I'm not sure I understand you. You have a Qt main window which contains some widgets arranged in a GUI. You want those same widgets to be accessible inside a web browser? Then you need to re-create all your GUI code in HTML, CSS and JS.
Your Qt app can use QHttp to listen for incoming client connections. When one of those comes, you reply with a webpage (written in HTML, CSS, JS). When this webpage is received by the user, his browser will display it. When the user interacts with the webpage, you'll probably want to send some data back to the Qt server eventually. You can do this either via form posting or via XMLHttpRequest.
You should know client-side web development is not that simple. Even when you know your languages, there's lots of things to learn about browser compatibility, security, accessiblity, JS app architecture, etc.
You want to make your application into an Http server. Here is an example using Qt to get you started:
http://doc.qt.nokia.com/solutions/4/qtservice/qtservice-example-server.html
As Stefan notes, this means putting your GUI into HTML/CSS/JS and more.
Related
I have a project which needs a little bit of web-scraping. The main requirement is to let the user enter his data on a java application. Then the application will connect to a data entry website then it will automatically inputs the data entered by the user to that website. I haven't started to code it since I don't know where to start. I already conducted some research about this and it points me to jsoup and desktop api(jsoup for webscraping and desktop api for opening a browser). Hope to receive a reply from the Java experts here.
Thanks!
JSoup will certainly do the scraping for you. However you need to handle HTTP (GETs/POSTs etc.) and for that I would recommend Apache Http Components.
I'm not sure you want to open a browser. Rather I would expect you to ask the user for input (perhaps via a Swing UI, or a browser-based UI) and then talk directly to the website using HTTP. I don't think you'd need to open a browser to the destination website. If you do, then check out Watij, which allows you to drive a browser directly from Java.
How to create web application using Qt?
This depends on what you mean by "web application". If you mean an application that can show parts of a web page in its interface as rendered HTML, like a browser can...yes. Qt incorporates something called QtWebKit:
http://doc.qt.io/qt-5/qtwebkit-index.html
(Note: Back in the olden days it was Microsoft--I think--who first made an embeddable Internet Explorer control so that you could fetch a URL into the midst of some MFC or VB application and run a browser in the midst of your otherwise-form-based application. The event hooks for Microsoft's solution sucked, Qt's are much better.)
Anyway, this is great if you want people to install your application on their machine, where it fetches web data but takes advantages of native features to be richer than a browser could. But be careful because these days native apps have to be really outstanding to surpass the advantage of something that runs in a browser they already have.
HOWEVER If you are trying to use QtCore to push server-side content out and fulfill web requests, that'll be an uphill battle. You might find some related examples if you look hard enough:
https://web.archive.org/web/20100922075100/http://labs.qt.nokia.com/2006/12/20/whats-this-cgi/
Very few people use C++ (much less Qt) to generate web pages server-side. Yet there are still some doing it, even in pretty cool ways:
http://www.webtoolkit.eu/wt
...regardless, QtCreator will be no help in that kind of pursuit.
The functionality you are asking for does not exist within Qt itself. However, there exists (at least) one third party library that allows some of the Qt code for a desktop app to be re-used to a certain extent for serving up a web app:
http://cutelyst.org/
However, this does not magically allow you to write a QML interface with QML Widgets and have a visual interface accessible via a web browser.
What do you mean by "web application"? Is it a desktop app with web features? If so, yes Qt in general is very good for that.
If you mean a kind of server that outputs HTML, then you should use something else because you would have to reinvent many wheels to make it work.
You'd require to run or embed web server. It would be more whise to turn to a Apache Web Server or Apache Tomcat based approach. Otherwhise you'd run somewhat against the odds.
Consider also using some HTTP server library like libonion or Wt. Wt is close in spirit to Qt. However, you won't use Qt itself. libonion is lower level (and you may want to use browser-side Web frameworks like e.g. JQuery or AngularJS with it).
If you already have some Web server, you could consider developing some FastCGI application in C++.
You surely need a good understanding of HTTP protocol and of HTML5 & AJAX.
Since this is 11 years old, I thought I'd come here to tell you that it does indeed seem possible now that qt supports webassembly. The newest version, 6.4 (newest version as of today jan 31 2023), now offers support for webassembly and their website has various examples of apps built with qt that run in the browser.
https://www.qt.io/qt-examples-for-webassembly
I'm contemplating adding a voice recording to some posts on my site. I'm wondering if there is an ASP.NET library out there that will allow me to:
Press a button to start recording
Record what I'm saying through my comp's built in microphone
Save the file as a .wav or some other popular sound file
As of now, I will be the sole user of this function, but it would still be nice to have in my bag of tricks in case I want to pull it out later for a client.
It is not doable without the help of a plugin. Browsers simply don't support voice recording.
You could choose from:
Make a SilverLight applet.
The flashPlayer can record too.
find a java Applet that can do this.
Make an activeX Plugin (since you have affinity to asp)
use your os provided voice recorder, save the file and upload it. Playback via browser is easy
You solution will involve a flash componet (outside of rendering the markup that invokes the flash component). The ASP.NET stack won't be able to do it. Silverlight doesn't seem able to do it.
Here is how.
Here's the problem: the browser does not allow this level of hardware access by an application. You could however achieve this either through Java, Flash or ActiveX (Yuk! don't do it) should the end user allow the access to occur however there are a number of cavaets. Here's a great thread where like-minded people like yourself are approaching the same challenge:
http://drupal.org/node/69242
If I were cornered to do this I would create a signed Java Applet.
not directly from asp.net since asp.net is server side and you need access to the client side microphone - however the new adobe flash player has the ability to access the mircophone so in theory you could use flash to record then upload to your site.
See ListenUp sdk. I found a bulletin board called english-test.net that is using the sdk to post voices.
You'll need some client-side code to achieve this as regular HTML doesn't support audio input and upload.
The ActiveX control Active Audio Record 2.0 claims to support recording audio and uploading it to an ASP.NET web server. I've never tried it though.
I am going to develope a module in ASP.Net. In this module I want to get the list of drives of the local system where this page is displaying. I have already tring with System.IO.... etc. but it gives me the server drives.
I want to get the list of LOCAL drive where page is displaying on server drives.
Thank you.
Do you mean the client's computer's drives?
That is not possible.
EDIT: However, it is possible with ActiveX or a browser plug in.
This absolutely cannot be done with neither server-side ASP.NET, nor with client-side JavaScript. You can try writing an ActiveX "control" (or how are these called?) or Java applet.
Fortunately you can not do that.
This is impossible, since your ASP.Net code runs on the server. The client only sees the rendered page (HTML and javascript).
Remember: your C# or VB.Net code runs on the server for the explicit purpose of sending html/javascript to the client browser. It does not get to peek directly at the "local" system, and the only thing the "local" system knows about is the html/javascript rendered on the server. That's just how the web works.
Furthermore, javascript runs in a sandbox that does not include any way to enumerate the local drives. This is by design.
So the only way to do this is via plug-in like flash, silverlight, or activex.
You can write a .NET control which is downloaded from your website to the clients' PC and looks at the drives there. As this could be abused (you could steal the users' files) you will have to convince the user to download the control in the first place. Look here for more info:
ClickOnce Deployment overview
I have a problem where a Web Application needs to (after interaction from the user via Javascript)
1) open a Windows Forms Application
2) send a parameter to the app (e.g. an ID)
Correspondingly, the Windows Forms Application should be able to
1) send parameters back to the Web Application (updating the URL is ok)
2) open the Web App in a new brower, if it does not exist
If many browser windows are open it's important that the correct one is updated.
Windows Forms Application is in ASP.NET
Browser is IE6+
The applications are controlled and internal for a specific organisation so it's not a question of launching a custom app.
Question A) Is this possible?
Question B) How do I send parameters to an open Windows Forms Application from a Web App?
Question C) If updating the Web App, how do I make sure the right browser is targeted?
What you're asking for is possible but seems awkward.
Trying to call an application from a web page is not something you could do due to security considerations. You could however make a desktop application which would be associated with a certain type of files and then use content-type on the web page to make sure that your app is called when a URL with this type is opened. It would be similar to the way MS Office handles .doc or .xls documents or the Media Player opens the .mp3 or .wmv files.
The second part (opening a particular web page from your application) is easier.
As you should know the address of your web page create a URL string with the parameters you want and open it in default browser (there are plenty of examples on how to do that, a sample is below).
System.Diagnostics.Process.Start("http://example.com?key=value");
If you want to update the page in the already opened browser or use a browser of your choice (i.e. always IE6 instead of Opera or Chrome) then you'll have to do some homework but it's still quite easy.
PokeIn library connects you desktop application to your web application in real time/per user. Moreover, due to its reverse ajax state management, you could consider both of your applications as one.
Check out
http://msdn.microsoft.com/en-us/library/8c6yea83(VS.85).aspx
Using VBScript in your Web Page you can call an open Windows Forms application and send keys to it.
This only works on IE though and you need to adjust the security settings to allow ActiveX.
Have a look into "registered protocols" (for example here and here). I know Skype does this to make outward phone calls from a web page. But probably some changes will be needed in the win application to intercept the parameters from the url.
I haven't tried this but it should be possible
No I don't think it's possible.
Think of viruses/trojans/spyware. If it were possible to launch an application from a mere HTML page, it would be very easy to install malware.
Browsers are designed to prevent you from doing that.
You could use clickonce to deploy and start the forms app - this should take care of sending the parameter to the app.
While this may not perfectly fit with your application, what about using a web service and the form?
Also, you can pass parameters to ensure IE6, not Firefox opens.
System.Diagnostics.Process.Start("c:\ie6\ie6.exe http://www.example.com/mypage");
Ok, so I actually found a clue to the web -> winform part.
The following code was handed to me from an web application that sends a parameter to a winform app. I assume this solution has some security factors in play (such as allowing running VBScript (and ActiveX?) in the webpage. That's ok for me though.
The code:
<script type="text/vbscript" language="vbscript">
<!--
Function OpenWinformApp(chSocialSecurityNumber)
Dim oWinformAppWebStart
Set oWinformAppWebStart = CreateObject("WinformAppWebStart.CWinformAppWebStart")
oWinformAppWebStart.OpenPersonForm CStr(chSocialSecurityNumber)
End Function
-->
</script>