Good place to start for client / server network programming? - c++

I have lots of experience with C++, (native) but I have never really ventured into network programming (example: games, chat software, or software that gets a file from a Web Site. )Where would be a good place to start for this? Preferably tutorials which are cross platform, and possibly some sort of project (not just theory). I ave found hundreds of great tutorials for C++, but few for Network programming) (which is not necessarily web programming).
Thanks

You can start with a simple HTTP server, which will lead you to HTTP protocol, file operations, multi-thread/event handling and etc. Or a distributed file system/cache system and etc. A lot of fun in it.

Boost.Asio is a fantastic cross-platform C++ networking library. The examples and tutorials are straightforward.
There's also plenty of help on stackoverflow in the boost-asio tag

Related

Web App and c++

It's something totally new for me, and since it seems to be something trivial, I can't find any response with our beloved friend ggle...
My question is : I have to create a webapp that can work if the client have nothing on his computer but a browser. My question is : is it possible to include to my project an external library (here I want to use PCL (Point Cloud library), a C++ library), and make it works even if the client have nothing installed? If I use QtWebKit for example, will I be able to create this kind of webapp?
Thanks a lot, and sorry for the (maybe) stupid question, I never did web dev before, it's my first time. ...
Have a nice day!
Wow, that question is as broad as the day is long, but here goes (you don't give too much about your background so I apologise if I am going too basic).
A web browser is just a piece of software that knows how to process HTML, CSS and Javascript passed over HTTP from a TCP socket.
So, on a most basic level, to get something to work in a browser all you need is to write a program that listens on a TCP socket and passes headers and HTML in the body of the response as per the HTTP protocol.
So, leaving aside the socket part, your method may look something like this:
std::cout << "<h1>Hello, world!</h1>" << std::endl;
In fact, the vast majority of the original dynamic web sites worked just like this: they were just C programs that just happened to produce HTML as output in the old days (cgi-bin).
The main issue with this approach is it's very tedious and time consuming to write code to that level of detail to generate HTML, especially when you factor in CSS and JavaScript.
This is one of the key reasons that most web applications these days are implemented in Java, .Net, Ruby, PHP etc as there is a wealth of fully-featured, stable and mature frameworks for web development that take the grunt work out of creating dynamic web sites (and C/C++ is much rarer).
However there are a couple of good frameworks out there for C++ if that is definitely the language you want to use.
Wikipedia has a limited section on C++ frameworks but it covers the 2 I would suggest investigating (CppCMS and Wt):
https://en.wikipedia.org/wiki/Comparison_of_web_frameworks#C.2B.2B
Of these, I've only had direct experience of CppCMS but I can recommend it - it's approach is idiomatic C++ (to my eyes at least, but I must confess I am more often a Java web developer than C++)
Also, there is quite a useful if slightly dogmatic SO discussion on this thread that may be relevant:
How popular is C++ for making websites/web applications?

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.

How to measure the SNMP performance of C when compared to other languages?

Iam looking at software that opens up a data set and grabs a list of server ips and pings them. Someone familar with this software packge says there is nothing else faster because the software is built on C++. Short of rebuilding the app in java is these anyway i can confirm what is the best language when building an app around snmp?
I know the question of C performance is posted all over the place but I do not see anything related to SNMP. When your core application is somthing like snmp is there a prefered programing lang?
The performance of an SNMP client isn't likely to have much to do with the implementation language. The network and the responsiveness of the server are the rate-determining steps.

Program interacting with web

How or what do I need to know programming wise in order to interact with the web using c++. For instance i want to wrote a program that automatically sends invites to players on yahoo chess. How would i go about doing this?
You'll need to understand the basics of TCP/IP and HTTP, possibly UDP, and the protocols involved with Yahoo's chess systems or posses a tool to work around them (A brief search leads me to believe there are few if any). You'll probably need a network API, I'd suggest looking at:
QtNetwork Module
Boost.Asio
Where Qt is easy to use, Asio is more powerful, and more 'C++' in nature. Qt has some nice webkit components, and I've used it to build a small web server, which was a lot of fun. You can accomplish quite a lot with it.
This page says they've added a captcha system to prevent certain people from interacting with their systems. I'm not familiar with Yahoo games and what the result of this has on what you'd want to do, however it suggests to me they'd rather you didn't write code to interact with their systems.
For this you need to use network APIs and use server side script like PHP/ASP to communicate with the web and C using message queue.

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.