Link C++ library to html front end - c++

I do computational research with a C++/CUDA library that does intensive number crunching. Recently I was thinking to set up a little showcase of my library on my webpage where people could work interactively with the library and see the results (plots, animations, etc.) in real time.
I have very limited html and website creating expertise. Are there libraries out there to link the html front-end to the C++/CUDA back-end? I'm developing in Linux environment but obviously I'd like my webpage to be accessed by anyone independent of their OS and/or browser.

So after a little bit of research I found the Wt library which is written in C++ and used for webpage development. Based on the information on their homepage, it seems to be exactly what I'm looking for:
Typical use scenarios:
High performance, complex web applications which are fully personalized (and thus cannot benefit from caching), fully Ajax enabled and at the same time entirely accessible and Search Engine Optimized.
Web-based GUIs for embedded systems benefit from the low footprint of a C++ web application server.
Web-based GUIs that require integration with (existing) C++ libraries, for example for scientific or engineering applications, or existing C++ desktop applications

I did something like this. To do this, I used a simple library I wrote called jrb_node at https://github.com/kennethho/jrb_node
There are other libraries like cppnetlib http://cpp-netlib.org/
Basically you make a small http server that based on the request will perform some computation and return the results as an http response. You can then combine that with javascript and Ajax if you want to make it more interactive.

An alternative to consider is to use WebCL. CUDA is pretty similar to OpenCL and it should be pretty easy to convert your code to the latter. If you have other C++ code, that might be a bit of problem though.

Do you want to run CUDA on server (e.g. the users will input the parameters, push a button and your server will do number crunching) or on client (e.g. it will be user GPU that does computations)?
For server-side you should be able to use pretty much any server technology - PHP, JSP, etc. They all provide a way to integrate to "native code".
For client-side you will not be able to do with just HTML - you need to use some "fat client" technology - e.g. ActiveX, Java applet. I do not know if Silverlight or Flash have access to native code. IMHO, you might as well just write a Qt application and put a download link on your site.

Related

Web Services using C++

I am building a server-client application that involves heavy signal processing (e.g. FFT). I have a working application written in C++/Qt, where everything (signal processing and other calculations) is done in client and server just sends raw data. Now I feel it would be easier to implement these features on the server. So, that maintenance becomes easier.
As I am doing signal processing, I think I should stick to C++ for performance. But I am open to new ideas.
Constraints:
I need type checking so javascript is out of discussion.
Scaling includes adding more server and each server will have at the max
10-12 users. So, Hardware cost is important. I cannot use x number of
i7 processors.
No option of using cloud services.
So, right now my question is as follows:
How can I create web services using C++ for Linux server? (Although cross platform is not important, I would appreciate if I can achieve it.)
EDIT [02:09:2015]
Right now, I think the choice is between poco and C++ Rest SDK. I feel I should go for C++ Rest SDK. Mainly because it has only those features that I need. And Also it is supported by microsoft and uses boost internally. So, I feel in future, this might be well integreated with standard.
You could use cross-platform Poco library to implement HTTP server, it is really straightforward with this framework, and they have a lot of examples. You can also use JSON serialization (like rapidjson library) to implement REST service on top of HTTP - this way your Web service will be accesable by most of the modern Web frameworks.
You might want to take a look at the C++ Rest SDK, an open source, cross platform API from Microsoft.
Like #nogard suggested, I also recommend POCO for now. It's the most serious and feature-full solution. Given you mentioned Qt, I suggest you to take a look at Tufão.
EDIT:
I forgot to mention one comparison of mine on the C++ HTTP server frameworks.
If you directly handle HTTP requests, you might loose the functionality what Web Servers does well what it was build to do. I had a similar issue, what I did was wrap up my Qt c++ code inside a PHP extension. In your case you can do the same. Wrap your logic inside what ever technology you are about to use, doesn't matter it's PHP, net , Java or anything else.

Creating gui binding for c++ and YUI

I am planning to use yui or jquery ui as front end for native c++ applications. I found no bindings present for this purpose. Will it be feasible/possible to do this ? If it is so, then how shall i proceed? please suggest advice.thanks
#rwik - I can see your point and desire to do what you intend and I would presume it to be a wise move to be making at this point in time considering the vast facilities browsers bring to the table as well as other aspects... I know we are in September now and I have come across this pretty late, but this is also for others who have a similar problem...
As far as I know, descending from JavaScript in to C++ is pretty murky, mostly due to the heterogenous nature of Javascript engines [Rhino, Tracemonkey, Spidermonkey, V8, Caracan,Charka, etc] employed by different browsers. But there are indeed ways to do this - depending on how dirty you want to get your hands and, indeed, on your abilities...
If you were to go with Google as a browser, you should take a look at projects such as cproxyv8 - http://code.google.com/p/cproxyv8/ or v8-juice - http://code.google.com/p/v8-juice/ which both offer interesting facilities...
My preference however is with Mozilla - simply because of XML User-Interface Language (XUL) which, if you do not know, allows you to speedily create your own user interfaces by giving direct access to its layout engine. I.e., you can even do away with the browser look and have your own independent layout while still having all browser facilities at your disposal.
With respect to C++/Javascript interaction - projects should exist for all alternatives - it pays to check.
I wish you good luck if you haven't already solved this problem.
I'd recommend QT instead.
However since native C++ has nothing to do with GUI I'm going to assume you are making a library in C++. However Yui is basically just JavaScript as is jQuery. So if you're asking can a web page or script be a C++ application the answer is not really.
What you could do is create a web service which uses your C++ library and exposes an interface for your web based application to call it indirectly.
One way to accomplish this is to embed WebKit into your application and provide your custom C++ functionality via a plugin. Both the WebKit framework on OSX and the Chromium Embedded Framework on Windows allow this style of application development. This allows you to write a UI using local Javascript/HTML files without the need for a webserver.
There are no direct bindings in JQuery and YUI because these libraries run in a web browser. Thus unless you’re planning to write your own browser plugins, the integration with the C++ will happen at the webserver that serves the data to the browser.
You could feed the data from your C++ code directly into JQuery/YUI by building web services directly in C++. But you might want to build a web application that will be serving your JQuery/YUI pages and that act as user interface controller (like in the MVC pattern). Web application languages like Java, PHP, etc. all have ways to call native code. Java has JNDI and in PHP you build extensions that link to C++ code.

Choosing Cross-Platform GUI Toolkit for Desktop App With WebServices

For a current project, we're designing a client desktop application that parses text files and interfaces with a web based database.
So far we've split the project into parts:
(Third-Party Program) -> (Our Desktop Client) -> (Our Parsing Library #1 and #2) -> (Our Web Server) -> (Our Verification Library) -> (Our Database)
We've hit confusion when it comes to choosing the correct way (and the best language) to make these pieces work together.
The third-party program's output is a simple text file, and we're just parsing it into a SQL-esque format for insertion into our database after verifying the numbers are in a certain range.
The first question we have is regarding the client language itself. We're planning on writing the parser libraries in C++ as they're just mostly text management. Our desktop client needs to be cross-platform for Windows and Mac. Currently we're leaning towards writing this in Java using Swing and the JNI. However, we realize there's a lot of hate for Java and that we'd have to worry about bundling in the JRE.
Is Java a good choice in this situation? Our other options seem to be writing this also in C++ using something like Qt for the GUI, or going platform specific and writing the windows version in .NET and then a Mac specific version. Our Windows community is the vast majority of users.
Our second issue is connecting this client with our web server. Originally we were just going to use an http POST to upload the file. We could also FTP the file which seems like overkill. We started to explore web services but were not sure if a web service could handle large amounts of text data.
Is there an easier way to do this? Everything is text, so it's no problem to send them in chunks or one giant string. If we go the web services route, will that effect our language choice for the desktop client?
There are definitely hundreds of ways to handle something like this, but most of these concepts are new for us. Any suggestions would be greatly appreciated.
Qt is an excellent choice and as it's native C++ it will be easy to integrate with your parsers too. Why write two versions when a single Qt version will run fine on both platforms with native look and feel? Depending on the license you choose you can even statically link Qt if you're concerned about deployment complexity.
A web service would generally have no problem handling large amounts of text and pretty much any language will interact with it easily assuming basic network I/O functionality. Depending on the language you will probably be able to find libraries that do most of the work for you, assuming it's not already supported natively.
As you say, there are many different ways to do what you want to achieve. There is no right or wrong way but obviously some designs will suit your needs better than others.

What works for web dev in C++

I want to create a web application that runs with very little RAM and I think C++ can help me achieve that.
Now, many people say C++ is unsuited for web development because:
there is no easy string manipulation
is an unsafe language (overflows, etc)
long change / build / test cycles
etc.
But I'm sure the C++ community have found ways to alleviate all those (maybe not the compile time) however since I'm not a regular so it is hard for me to put a value on what I find in Google.
So I'm asking for some guidance. I would appreciate if you share what works, what tools/libs are current and alive. What strategies can help with web dev in C++? FastCGI or embedded server (Asio / POCO / Pion / etc.)? How do you address security concerns?
Thanks a lot for any help
Have you looked at http://www.tntnet.org/. They have created a... well let me cut and paste from their website:
Tntnet is a modular, multithreaded,
high performance webapplicationserver
for C++. To create webapplications
Tntnet has a template-language called
ecpp similar to php, jsp or mason,
where you can embed c++-code inside a
html-page to generate active content.
The ecpp-files are precompiled to
c++-classes called components and
compiled and linked into a shared
library. This process is done at
compiletime.
I've used it and it has quite a small overhead plus it has screamingly fast dynamic page generation. Makes PHP, Ruby etc snails in comparison because with tntnet you are running compiled C/C++ code.
There's the Wt Project. It uses a paradigm similar to Qt's signals/slots.
There is nothing wrong with trying to build a web app in C++. It's actually a lot of fun. What you need is a:
Templating system
A CGI lib
A database API wrapper, most likely, to avoid dealing with something like the low-level MySQL API
A logger
ATL Server is a library of C++ classes that allow developers to build internet based applications.
ATL Server. It's open source too! And of course there is always ISAPI. Ah, the bad old days. :)
In your other question you mention that your embedded system is openwrt. As this router firmware already comes with a embedded web server (for it's administration UI), why don't you use that for you app as well?
Our web app backend is in C++ via CGI and we use Clearsilver templates along with the HDF that comes with it.
Give us some more hints about what you're trying to do.
You can write a good old-fashioned cgi program in C++ easily enough, and run it with FastCGI. We used to do that all the time.
You could write a C++ program embedding a lightweight HTTP server as well.
Both of them are much bigger PITAs than using something like perl or ruby.
So for why C++?
Update
Okay, got it. The main thing about FastCGI is that it avoids a fork-exec to run your CGI program, but it is a little bit different API. That's good, but you still have the problem of handling the HTTP stuff.
There are, however, several very lightweight HTTP servers, like Cherokee and Lighttpd. In similar situations (building web interfaces for appliances) I've seen people use one of these and run their C/C++ programs under them as a CGI. Lighttpd in particular seems to concentrate on making CGI-like stuff fast and efficient.
Another update. I just had cgicc pointed out to me: http://www.gnu.org/software/cgicc/
That might solve some problems.
You can try Cutelyst a C++11 built with Qt, with one of the best positions on TechEmpower Benchmarks.
Even though it requires Qt 5.6+ a full CMS (CMlyst) uses around 6MB of RAM while serving around 3000 requests per seconds on a single core.
And for your string manipulation issue QString is just an amazing class for that.

What embedded browser for C++ project?

Is there any browser I could embedd in C++ application on Windows?
I need all features typical browser has (HTTP client, cookies support, DOM style HTML parser, JavaScript engine) except rendering.
Because I don't need rendering capability (and that's rather big part of a browser) I would prefer a browser with non monolithic design so I wouldn't have to include rendering stuff into my project.
It would be nice if it had C++ rather than C API.
I need this embedded browser mainly because I have much trouble finding C++ HTML parser which could handle broken HTML like browsers do.
If you know any, please answer Library Recommendation: C++ HTML Parser SO question or at least vote on it to increase a chance someone will give a good answer.
Sounds like all you need is something like libcurl which is an HTTP library and will let you do GET/POST/etc.
When I think browser I generally think rendering/JavaScript and not HTTP library.
Edit
In that case I'd look at WebKit (which I think has a C++ API) and hope you don't have to pull too much in.
Edit Again
On second thought (since rendering is such a big part of what browsers do), you might be better off using a stand-alone JS engine like SpiderMonkey and a stand-alone XML parser like Xerces-C (plus maybe tidy to make your HTML into XML).
I'm a bit confused by your question regarding embedding a web browser for which you don't need rendering capabilities. A web browser is rendering web pages by definition, unless you just need HTTP and XML with JavaScript capabilities which is a subset of a browser functionalities?
If you need a web browser to embed in your C++ application, I would suggest to consider Qt that comes with the WebKit plugin. It is C++, LGPL and has a very nice IDE (Qt Creator). I tried Qt with Qt Creator on unix (Ubuntu) and it was very impressive. The debugger is a bit light but it is just the first version. The adapter of Qt into visual c++ 2008 is now free.
You might also want to check out Awesomium-- it's free for non-commercial use and has all of the features you're looking for (if you don't need rendering, simply don't use it).
There is a project called CEF = The Chromium Embedded Framework - it is:
a simple framework for
embedding Chromium-based browsers in other applications. It is a
BSD-licensed open source project founded by Marshall Greenblatt in
2008 and based on the Google Chromium project. Unlike the Chromium
project itself, which focuses mainly on Google Chrome application
development, CEF focuses on facilitating embedded browser use cases in
third-party applications.
and yes:
The base CEF framework includes support for the C and C++ programming
languages.
Including javascript support and html parsing makes this non-trivial task - you have to use one of the available browsers.
IE is usable through its COM model - you can create instance of it in your window be it invisible or not and call its javascript/html capabilities.
It has been designed to be used like that since the beginning and certainly it is working fine.
The other options are:
Gecko/Mozilla - a couple of years ago it wasn't usable like this, currently I think it is.
WebKit/V8 - no public API has been released for chrome yet, you could use webkit itself, but it doesn't have javascript engine. Another option is to take a look at the Chrome codebase and see if you could get out of it what you need.
I would probably go for IE, since it is maybe the easiest option and I have already used it. The other options seem to me more like building a browser instead of just using it.
How about Gecko ? You may not need the entire engine but you may find some its components useful like SpiderMonkey which is a JavaScript engine written in C.
I'd recommend picking up Qt for C++ programming. It has a built-in library that embeds Webkit with all the bells'n'whistles, and Qt is a great C++ library in general.
Old question, I know, but take a look on
http://msdn.microsoft.com/en-us/library/ky29ffxd%28v=vs.94%29.aspx
IActiveScript and family COM interfaces allows script execution (not only JS, any language that registers as script interpeter, for that matter) in-memory.