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.
Related
What is a good choice for a simple http Server lib? It doesn't need high performance. I rather look for something simple for some REST/JSON communication ("API").
It must be able though to work in a multithreaded environment and must be able to handle large POST request.
Any suggestions? I already tried cpp-netlib but this seems to be much too complicated for such an easy task...
Edit: I am looking for something really light-weight and simple. E.g. like Sinatra in the Ruby world. Poco is for me another example of a too heavy-weight library.
The first one that comes to mind is Poco Library ( http://pocoproject.org/ )
Cross platform, stable, well documented. While the library itself offers more than you probably need you can build and omit the portions you aren't planning on using to reduce bloat.
They have a fully featured Net library that includes several salient classes and utilities.
Here is a pdf of slides from that library, of particular interest is the HTTPServer class:
http://pocoproject.org/slides/200-Network.pdf
Not sure about large POST data, but I've previously used mongoose: https://github.com/cesanta/mongoose/.
If the LGPL license is unwanted there is a MIT fork from when the project was MIT that also add a C++ API https://github.com/bel2125/civetweb
I would encourage you to start with http server samples in boost.asio. They are so simple and easy to understand, that you should be able to easily extend them as needed.
However, if you want to jump onto something more polished than just sample code, I know of 3 http servers in C++ which you may like to try:
"x0 - HTTP Web Server Framework" to me personally this one seems most promising, because it's lightweight and simple
"highpower / xiva" is a simple http server framework for delivering notifications to browsers
"Pion, a project of Atomic Labs" is a part of elaborate framework for handling large amounts of data
Pretty late answer; but hope this helps.
For your interest of a server that can handle REST, here is the easiest HTTP Server library to use (in my opinion): https://github.com/yhirose/cpp-httplib.
For JSON parsing, you may search for another library to use it in conjunction.
Personally, I'd go for Arachnida but that might be because I wrote it.
Does anyone know of any really good C++ Libraries for implementing a web services api over top of existing legacy code?
I've got two portions that are in need of it:
An old-school client/server api (No, not web based, that's the problem)
An old cgi application that it integrates with the client and server.
Let me know if you've had any luck in the past implementing something like this using the library.
Microsoft has put out native code webservices API (WWSAPI) that looks pretty decent. I haven't had a chance to use it yet. We had originally ignored it, since it required Windows 7 or Server 2008, but they've finally released a runtime library for older OSs.
I would advise staying away from Microsoft's old SOAP SDK. For one, it's been deprecated; two, it's not terribly easy to distribute; and three, it's terrible to code for compared to the .NET offerings.
What we've done is written a bit of C++\CLI to interface our existing C++ codebase with .NETs webservice framework. This turned out to be remarkably easy. .NET will generate all the classes and boilerplate code you need based of of a WSDL file. Then you just write some C++\CLI code to handle the incoming data as managed classes and fill in some managed classes as responses.
You can use the Apache AXIS/C interface to build a web services interface. It has plugins for Apache and IIS (and I think FastCGI), and lets you talk web services to your legacy code.
I used gSOAP in a project and it was quite straightforward. Compared to Axis/C, I found it easier to learn and use. I never used POCO, can't give you an opinion, but it's gaining popularity recently. This is the link for gSOAP
http://www.cs.fsu.edu/~engelen/soap.html
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.
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.
I have recently been given a task to add the ability to interact with Web Map Services to an existing MFC application and I am in need of a client-side HTTP API.
Based on my research, the leading candidates seem to be CAtlHttpClient and WinHTTP. I was curious to see if anyone had experiences they could share or opinions on which would be the better way to go (or suggestions for something else entirely).
At first glance, CAtlHttpClient seems to be a bit higher level and easier to use. However, in my research it seemed that any time people had a problem with not being able to do something with it, the answer was "use WinHTTP".
Result
I wound up using WinHTTP because WinInet displays dialog boxes and our application is usable through a COM API. I avoided Ultimate TCP/IP because I work for a large company and getting third party software approved for use in a product is a complete nightmare.
The simplest one is the WinInet MFC wrappers: CInternetSession and friends.
WinHTTP, although a different API, is built on the same model as WinInet yet provides better HTTP support (no FTP though but you probably don't care). Whether you need the extra goodies provided by WinHTTP should be examined.
A down side of WinHTTP is that ATL/MFC don't provide wrappers for it, as opposed to WinInet.
And as Rob mentioned, UltimateTCP is a excellent alternative. One of its advantages is that it's a library: you link the code into your application, thereby eliminating DLL hell potential problems. Also, it comes with full source code which might be convenient if you run into a limitation of the implementation.
Make your pick!
Try Ultimate TCP/IP available for free from here:
http://www.codeproject.com/KB/MFC/UltimateTCPIP.aspx
It's a very good library and very easy to integrate with your apps.