for one of my applications I'd like to provide a minimal web interface. This core application is written in C++ and uses Qt4 as a framework. Since I'm also using some libraries I wrote to calculate some things and do some complex data management, I'd like to use this existing code as a backend to the web interface.
Idea 1: Using an embedded web server
The first thing I tried (and which worked to some degree) was using an embedded web server (mongoose). As you can imagine, it is just a very thin library and you have to implement a lot of things yourself (like session management, cookies, etc.).
Idea 2: Using a normal web server and adding a fcgi/cgi/scgi backend to my application
The next thing that came to my head was using a mature but compact web server (for instance, lighttpd) and simple provide a fcgi/scgi/cgi backend to it. I could write the web application using a good framework, like Pylons, PHP, or RoR, (...) and simply have an URL prefix, like /a/... which allows me to directly talk to the backend.
I tried to implement the libfcgi into my application, but it looks messier than needed (for instance you'd have to implement your own TCP/IP sockets to pass on data between your app and the web server and tunnel it through the FCGI library, meh)
Idea 3: Creating a command line version of my application which does the most basic things and use a normal web server and framework to do the rest
This is the third idea that came to my head. It is basically about creating a web application using a traditional way (PHP, RoR, etc.) and using a command line version of my application to process data and return it when needed.
I've got some experience with creating web applications, but I never had to do something like this, so I'd like to hear some ideas or suggestions. I'd like to use JavaScript on the browsers (AJAX, that is) and pass some JSON constructs between web browser and server to make the user experience a bit smoother.
So what are your suggestions, ideas on this? I don't want to re-invent the wheel, honestly.
I would never expose a custom written application to the net as front-end, for that servers like apache or lighthttp are build. They give you some serious security out of the box.
As for interaction of your app with that webserver, it depends a bit on the load and what kind of experience you have with writing software in PHP, python or other languages supported by your web server (via interpreter of course).
A slight load, and a command line tool accessed from PHP might do perfectly well.
A more heavy load and you might wish to implement a simple (SOAP?) server with Qt and access that from a python (or php) script.
That way you don't need to do layout in you app, and you also don't need to implement security all that much.
I'm currently researching a similar situation (custom web app backend using Qt), and the least bad option is FastCGI. Found something you might be interested in. Not production ready without some serious testing, but this might be a good starting point for Qt - FastCGI interop: FastCGIQt
I've used the FastCGI Protocol Driver library for a similar project (also a Qt application), the download link is at the end of that page [Libfastcgi]. Integration with the application turned out actually comparatively easy. Lighttpd + mod_fastcgi was used as web server. Can't say anything about FastCGIQt, though.
You Wt works well to provide a web interface to Qt based applications. Both have a similar programming style, and there's an example that demonstrates the integration with Qt.
Here is example of embedded QML-server: https://github.com/ncp1402/ql-server
Related
Is it possible to communicate from a web browser(Loaded an HTM page from server) to an application running in the same server using AJAX. Need to send the request from browser using a button click and update the page with responses received from one another application running in the same server machine?
I am using HTML pages to create website and not using any PHP or ASP like server side scripting. In server machine data are manipulated using a C++ application.
I think you can use any sort of Javascript functions to do that. But you might need to use jQuery or similar frameworks to make your live easier. You might need to search for "Comet Programming" to know exactly how to do 2-way communication between client and server
Updated:
Well, this kind of stuff requires you to read a lot (if you have not already known). Basically, what you need is a server that can do long-polling (or eventsource, websockets). There are many open-source ones that might help you to get started. I can list a several good ones here. There are a lot more
http://www.ape-project.org/
http://cometd.org/
http://socket.io/
http://code.google.com/p/erlycomet/
http://faye.jcoglan.com/
So after you have the comet server up and running you will need to setup the client side (probably Javascript). For those listed projects, most of them come with the client side code to interact with the server (Except for erlycomet). Therefore, you can just use the examples provided and run a quick prototype. If you want to use your raspberry pi, you can use nodejs which provide a lot of ease for dealing with real-time communication (socket.io, faye). And lately, http://www.meteor.com/
I would think of the problem this way: you want to provide a web front end to an existing c++ application. To achieve this you need to think about how your web server communicates with your c++ application. Communication between the browser and web server can be thought of as a separate problem - as you say AJAX calls can be used, or maybe have a look at websockets.
Once you have your request in the web server you need to communicate it to the C++ application (and/or visa versa). This can be done a number of ways, e.g. sockets or RPC. I found this question here which has some good advice.
We're about to start a new project and I've been looking at some of the new web technologies. We want to build a RESTful api which a client can access. To date we've been using python with django/flask to build the api and using jquery for the front end.
I've read quite a bit on javascript frameworks such as emberjs and angular, as well as nodejs solutions like express, meteor and derby. I really like the idea that a site should 'auto update' when the model changes.I'm aware that there are some libraries like gevent which can help facilitate socket level communication, but it seems to be more of a patch than an elegant solution.
Ideally, I don't want to give up a proven technology, ie writing server code in python (or php,ruby whatever) for building my whole app on nodejs. Having a RESTful API is important since we want our services to be open and accessible.
Would it be a bad idea to have 2 servers and 1 client? 1 traditional api server communicating with a javascript framework on the client. Then also run a nodejs server alongside the api server which can somehow talk to the api and if it finds updates, passes it along to the client.
We want to build a RESTful api which a client can access.
Ideally, I don't want to give up a proven technology, ie writing server code in python (or php,ruby whatever) for building my whole app on nodejs.
Then you should probably go with Rails and Ember.js. I'll quote eviltrout (co-founder of discourse) which is build on ember and rails:
One amazing side effect of a rich client side app is you end up with a battle tested API. Our app has consumed our own API since day one, so we know it works.
If we want to create a native client for Android or iOS, it would be a lot easier because we already speak JSON fluently. If people want to build services that use Discourse, they won’t have to result to screen scraping. It’s a huge win for us and the developers that use our platform. 1
However you should keep in mind that ember is as of to date still a very young framework (rc3 v1.0.0).
I don't know what sort of application you are building (in respect to why you would want to use node) How to decide when to use Node.js?
I am looking for the best way to add support for a REST based Web Service to an MFC C++ Application. This is legacy code that has been around a long time.
I need to have the Application provide the Web Service. I've researched this, and the articles are about consuming Web Services in a C++ App. I envision having to monitor a port and respond to the HTTP requests. It would probably make more sense to tie in with WCF and IIS, but I am not sure how to move forward.
I already have a tool of "making" this App into a Windows Service. I realize it would be better to have a "real" app, and this is what I have to work with. There is so much logic in this code and we are limited in development time, so we are taking the fastest approach possible. We also cannot use DCOM, as the Web Service will be called by a Linux based system.
Any suggested articles would be much appreciated.
For C++ you can test two libraries WSF/C and gSoap, another alternative is to develop it with C# and WCF , and communicate between C# and C++ using C++\CLI.
I use the Poco Net c++ library for this as it supports both HTTP client and server functionality. I considered various other libraries including Boost based stuff, but other than Poco I struggled to find everything I needed in one tidy package. It also has some easy to use mutex support which became essential for me as soon as I added a web server front-end to what had previously been a simple single threaded console app. Poco is cross platform but I mainly use it windows and it has served me well to date. I'm not very clued up on MFC so I don't know how it would get on in that department though.
I am pretty new to web programming.I am developing a HTML5 based user interface which is supposed to use a middle ware written in C/C++.How can I do this?
I do not want to use any browser specific feature/library to communicate with the middle ware. Can we do the same at the server side and then send back the information to the browser? If so how can I achieve this communication with the middle ware at the server side?
Thanks in advance for the reply.
Note : I am planning to use Tomcat as the server in loop back.
As suggested above, you could use CGI (e.g., perl scripts) as a middle-man between the Tomcat server and your C++ middleware. What I also think might work well, and am planning on using myself in the near future, is to use boost::asio, and take the example HTTP server and modify it to use your middleware. You could then communicate between the Tomcat server and the C++ server using AJAX with JSON.
There is also something called pion server http://www.pion.org/projects/pion-network-library
It allows you to write the entire server in your own C++, with most of the common tasks abstracted away.
The Wt "web toolkit" library (pronounced "witty") may be of interest. Essentially all web-aspects are taken care of this, so absolutely no middleware. Here is an intro, quoting from the website:
The API is widget-centric and uses well-tested patterns of desktop GUI
development tailored to the web. To the developer, it offers
abstraction of web-specific implementation details, including
client-server protocols, event handling, graphics support, graceful
degradation (or progressive enhancement), and URL handling.
Unlike many page-based frameworks, Wt was designed for creating
stateful applications that are at the same time highly interactive
(leveraging techinques such as WebSockets and Ajax to their fullest)
and accessible (supporting plain HTML browsers), using automatic
graceful degradation or progressive enhancement. Things that are
natural and simple with Wt would require an impractical amount of
effort otherwise: switching widgets using animations, while being
perfectly indexed by search robots with clean URLs, or having a
persistent chat widget open throughout, that even works in legacy
browsers like Microsoft Internet Explorer 6.
It can run with its own web server (based on a Boost component) or be linked against standard web server libraries.
I wrote a short blog post about how to integrate it with another C++ component I wrote (RInside, which permits to embed R inside C++ apps) and by joining the two, I had a simple 'webapp' exporting R functionality to the web.
You can further enhance it via Javascript but that is something I have not looked into in any detail.
I am having a desktop application which having a UI interface made in Qt linked with a library which is doing all the calculation stuff. Values from UI is taken and pass to the API's in the DLL to get the output which is shown on Screen.
Now i want to do the same thing by transferring my application UI to a web page so that people can access the tool from anywhere without any installation process.
I want to retain my c++ DLL code so i don't have to do a lot of work. I am thinking of just converting this DLL to a C++ server by any communication Process(Sockets). I want to host this application on my company's website. (We have to make the website also so we are open to any set of tools).
I want to know what will be the best set of tools to do this stuff. Also there will be lot of data exchange between the webpage and server so the wholething should be optimized also. I goggled a bit and find stuff like silverlight and ASP.NET, But i am still not very clear which option will be more suitable.
I am a c++ programmer with no web application development experience. I am open to learn any new technology.
Thanks
Why not use Qt on the web directly? There are several projects like this one: http://qtwui.sourceforge.net/
There is a netscape plugin that will host a QT application and an ActiveX control wrapper on the QT website. You could use one of those to wrap your application. Note that this approach would require the user (or their administrator) to download and install the plugin.
An alternative approach might be to run your application through a remote desktop such as XVNC, NX or an RDP based layer. IIRC browser based remote desktop clients are available for most such protocols.
A few options:
pick a messaging/queue implementation (like http://www.zeromq.org/) and provide a service
implement a Windows Web Service if you want to be more enterprise friendly: http://msdn.microsoft.com/en-us/magazine/ee335693.aspx
I would not expose the implementation on the internet. Enough to have a simple buffer overflow and the machine can be taken over quickly. Adding a layer between the app and the web provides an easy way to validate input, access, stats ...
You should be able to use your DLL from an wt or cppcms application. Then you do not have to learn something new and can just use C++.
The way I'm currently doing this is with Boost.Python + django