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.
Related
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.
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.
Is there a relatively easy way to display the output of a C++ program on a webpage? And I don't mean manually, in other words, you see it on a webpage as it runs not as in I make a code tag and write it in myself.
EDIT: Just so everybody can get this clear I am going to post this up here. I am NOT trying to make a webpage in C++. Please excuse me if this sounds spiteful or anything but I am getting a lot of answers relating to that.
Step one, get yourself a server-side language. Be that PHP, ASP, Python, Ruby, whatever. Get it set up so you can serve it.
Step two, find your language's exec equivalent. Practically all of them have them. It'll let you run a command as if it were from the command line, usually with arguments and capture the output. Here's PHP's:
http://php.net/manual/en/function.exec.php
Of course, if you're passing user-input as arguments, sanitise!
I've just seen that you accepted Scott's answer. I usually wouldn't chase up a SO thread so persistently but I fear you're about to make a mistake that you'll come to regret down the line. Giving direct access to your program and its own built-in server is a terrible idea for two reasons:
You waste a day implementing this built-in server and then getting it to persist and testing it
More importantly, you've just opened up another attack vector into your server. When it comes to security, keep it simple.
You're far better having your C++ app running behind another (mature) server side language as all the work is done for you and it can filter the input to keep things safe.
You could write a CGI app in C++, or you could use an existing web server language to execute the command and send the output to the client.
You want to use Witty.
Wt (pronounced 'witty') is a C++
library for developing interactive web
applications.
The API is widget-centric and similar
to desktop GUI APIs. To the developer,
it offers complete abstraction of any
web-specific implementation details,
including event handling, graphics
support, graceful degradation (or
progressive enhancement), and pretty
URLs.
Unlike many page-based frameworks, Wt
was designed for creating stateful
applications that are at the same time
highly interactive (leveraging
techinques such as AJAX to their
fullest) and accessible (supporting
plain HTML browsers), using automatic
graceful degradation or progressive
enhancement.
The library comes with an application
server that acts as a stand-alone web
server or integrates through FastCGI
with other web servers.
I am not sure this is what you are looking for but you may want CGI You may want to look at this SO question, C++ may not be the best language for what you want to do.
based off the questions you posted Writing a web app like what you want is no simple task. What I would recommend is use some other library (this is one i found with a quick google) to get a web console on your server and give the user it is running under execute deny permissions on every folder except the folder you have your app installed.
This is still is a risky method if you don't set up the security correctly but it is the easiest solution without digging around too much on existing libraries to just have the application interactive.
EDIT --
The "Best" solution is learn AJAX and have your program post its own pages with it but like I said, it will not be easy.
It sounds like you want something like a telnet session embedded in a webpage. A quick google turns up many Java telnet apps, though I'm not qualified to evaluate which would be most ideal to embed in html.
You would set up the login script on the host machine to run your c++ app and the user would interact with it through the shell window. Note though that this will only work for pure command line apps. If you want to use a GUI app in this way, then you should look into remote desktop software or VNC.
It may be worth looking into Adobe's "Alchemy" project on Adobe Labs
This may help you with what you're trying to achieve.
:)
Are you looking for something like what codepad.org does? I believe they explain how they did it here.
There is a library called C++ Server Pages - Poco. I used it for one of my college project, its pretty good. There is also good documentation to get started with, u can find it here http://pocoproject.org/docs/
I have a few years experience programming c++ and a little less then that using Qt. I built a data mining software using Qt and I want to make it available online. Unfortunately, I know close to nothing about web programming. Firstly, how easy or hard is this to do and what is the best way to go about it?
Supposing I am looking to hire someone to make me a secure, long-term, extensible, website for an online software service, what skill set should I be looking for?
Edit:
I want to make my question a little more specific:
How can I take a bunch of working c++ functions and port the code so I can run it server side on a website?
Once this is done, would it be easy to make changes to the c++ code and have the algorithm automatically update on the site?
What technologies would be involved? Are there any cloud computing platforms that would be good for something like this?
#Niklaos-what does it mean to build a library and how does one do that?
You might want to have a look at Wt[1]. Its a C++ web framework which is programmed more or less like a desktop GUI application. One of the use cases quoted is to bring legacy apps into the web.
[1] http://www.webtoolkit.eu
Port the functions to Java, easily done from C++, you can even find some tools to help - don't trust them implicitly but they could provide a boost.
See longer answer below.
Wrap them in a web application, and deploy them on Google App-Engine.
Java version of a library would be a jar file.
If you really want to be able to update the algorithm implementation dynamically, then you could implement them in Groovy, and upload changes through a form on your webapp, either as files or as a big text block, need to consider version control.
The effort/skillset involved to perform the task depends on how your wrote your code. If it is in a self-contained library, and has a clean (re-entrant, thread safe) API, you could probably hire a web developer (html/php/asp etc) to write the UI interface to the library for a relatively small cost. The skills required would be dependant on the technologies you wanted to use. For Windows development I would suggest C#/ASP. The applicant would require knowledge of interfacing with native libraries from a managed language. This is assuming that you dont mind the costs of Windows deployment for your application.
On the otherhand, if the library is complex or needs to be re-written to support the extensibility you are looking for, asking here will not get you much.
BTW: here is a great article on Marshalling if you chose to implement using C#/ASP
http://msdn.microsoft.com/en-us/magazine/cc164193.aspx
First, DO NOT USE PHP :D
I used it for some projects (the last one with symphony framework) and i almost shoot my self !
If you are very familiar with C++, ASP .NET could be a good solution because if you like C++ you are going to love C#.
Any ways, I personally use Ruby on Rails for 6 months now and I LOVE IT. I won't write you a book here but the framework is pure gold !
The only problem is that Ruby is a very special language. You will probably be a bit lost a the beginning. But as every one you will learn to love it.
But that was only for the server side. Indeed, there 3 technologies you won't be able to avoid if you want to start to develop web applications.
HTML, CSS and JavaScript are presents every where. This is why i'm thinking you should start by HTML and CSS then JavaScript (with jQuery).
When you've got some basics with these 3 technologies you should be able to choose the server side language.
But you've got to tell you one thing, it's not going to be easy !
PS : Ruby on Rails uses HAML and SASS. These 2 languages replaces HTML and CSS you should have a look at them quickly because they are awesome.
I'm looking at doing some work (for fun) in a compiled language to run some simple tests and benchmarks against php.
Basically I'd like to see what other people use for C++ CGI programming. (Including backend database, like mysql++ or something else)
I'm not sure exactly what you're looking for, but there is a C++ web framework called wt (pronounced "witty"). It's been kept pretty much up to date and if you want robust C++ server-side code, this is probably what you're looking for.
You can check it out and read more at the wt homepage.
P.S. You may have some trouble installing wt if you don't have experience with *nix or C++ libraries. There are walkthroughs but since frameworks like these are the road less traveled, expect to hit a few bumps.
Another option is the Cgicc library which appears to be mature (currently at version 3.x):
http://www.gnu.org/software/cgicc/
If I were thinking of working at that level, I'd probably just write a straight-up Apache or IIS module instead of a CGI.
That said, if you do want to go with CGI, I'd suggest using the venerable cgic from Thomas Boutell. It's a "plain" C library, but it's been in constant use since the mid '90s so it's thoroughly tested and solid as a rock.
Check out Boost's C++ CGI class, which is not a part of boost yet.
In short, I don't think there is such a thing for generic server CGI programming (happy to be proven wrong of course).
Instead you'll probably have to target the server APIs, such as Apache's. This looks like a reasonable introduction to request processing, which will be a big part of what you're doing.
As an alternative, Lighttpd may be even more developer-friendly, and (particularly if you're looking at performance) faster.
I note there's a cpp-netlib under development but it seems to be HTTP client only.
I've found very pleasant to use CppCMS to develop a Fast CGI app to deploy in a nginx server - although it never went in production =( . The CppCMS project also includes some libraries for SQL connectivity.