How to call a Rest Service in C++? - c++

I want to call a rest service written in WCF (which can support both XML and JSON Web Message Formats) from my C++ application.
What is the best solution to achieve this ? I have seen some utilities (gsoap) which create proxy classes for you to be used to call web services.
Can I achieve the same functionality without using any intermediate utility ? As its a rest service and it works using GET/PUT functions which are basic HTTP functions, is there any C++ library/Solution which could be used to invoke these function directly from a c++ application ?

On Linux, you probably could use curl library (and I guess it is ported to Windows). Curl is a library providing HTTP client functionality to a C or C++ program.

Use Casablanca. This should be helpful for people looking for this answer in 2013. CURL is perfectly appropriate but if you're doing C++ in Windows and using MS stuff, Casablanca seems fit.

Hope the following articles might be of help to you
1. Accessing an XML Web Service Using C++
2. SOAP client for C++

I tried gsoap myself but it became difficult to maintain cross platform versions of my app.
Instead i went the HTTP request route.
For cross platform and C++ i found this Call Rest Web Services from C++

If XML serialization with your REST approach is really not needed then curl is perfect to use. However, if you want type-safe XML serialization in C or C++ then it would become cumbersome to use curl, since you will have to use something that runs on top of curl to process XML such as with a DOM parser (slow and not type safe). If you have a WSDL, then I recommend gSOAP 2.8 which provides integrated REST and XML serialization capabilities (and JSON when you need it).

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.

How to make HTTP POST/GET in a c++ metro app?

I have a some web services that my app needs to communicate with by sending json with REST over HTTP POST/GET. The only way I can see to do this is with the iXMLHTTPRequest2 framework but geeze oh man is it uglier than I want to deal with.
Is this the only option I have to look at with c++?
Would this be easier with c#? I know most of the things are the same across the languages, but if c# has a better way to do this, I'd be willing to make the jump.
You should also look into Project Casablanca - it's a fully native C++ library that also is adapted for use with Metro apps (I believe it wraps IXHR2). I've been using it to perform http REST calls and to parse JSON very successfully.
That's the interface you have to use in C++. It is more difficult than in C#. Given that, there is a good sample that will make using that interface a bit more bearable.

C++ Library for implementing a web services api over legacy code?

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

Download File from Web C++ (with winsock?)

I need to download files/read strings from a specified url in C++. I've done some research with this, cURL seems to be the most popular method. Also, I've used it before in PHP. The problem with cURL is that the lib is huge, and my file has to be small. I think you can do it with winsock, but I can't find any simple examples. If you have a simple winsock example, a light cURL/Something else, or anything that could get the job done. I would greatly appreciated. Also, I need this to work with native C++.
I can repeat me answer Is it possible to handle proxies at socket level? (see also comments) about two important interfaces Windows Internet (WinINet) API and Windows HTTP Services (WinHTTP). An important restriction of WinINet is that WinINet should be not used in a service (only in GUI app.) because of possible dialogs.
you should try WinInet: this library is part of Windows operating system, and allows to download a resource identified by an URL, using either HTTP or FTP.
if you are using HTTP, you might find the InternetOpenUrl() function useful.

C++ web service framework

We are looking for a C++ Soap web services framework that support RPC, preferably open source.
Any recommendations?
WSO2 Web Services Framework for C++ (WSO2 WSF/C++), a binding of WSO2 WSF/C into C++ is a C++ extension for consuming Web Services in C++.
http://wso2.org/projects/wsf/cpp
Apache Axis is an open source, XML based Web service framework. It consists of a Java and a C++ implementation of the SOAP server, and various utilities and APIs for generating and deploying Web service applications.
http://ws.apache.org/axis/
http://code.google.com/p/staff/
Staff is Web Service Framework for C++ (service/component and client-side)/JavaScript(client-side) based on Apache Axis2/C.
Open-source, released with Apache License V2.0.
Try the ffead-cpp framework, it provides in-built web-service support, rest, json and many other useful features.
We are using EasySoap (http://easysoap.sourceforge.net/)
While not FOSS another library is ATL Server library from Microsoft.
It is C++ template based with some proprietary attributes by Microsoft. i.e. not standard C++
You can check out xmlbeansxx. This is a kind of lightweight, low level solution, compared to complete frameworks. This has advantages in some cases.
Invoking SOAP WebServices using xmlbeansxx Article
Code example is here:
WsClient.cpp.
You could try gSOAP. Available under GPL and commercial licences.
I have used SWIG to make an interface from C++ to Java or Python and then used the typical web interface support for those languages.
Since Java and Python have reflection the web services frameworks that exist for them have a much easier time passing data around.
Threading wise if your C++ code is thread safe you can let the Java server manage the creation of threads for concurrent requests etc. and just call into your C++ code using JNI.
As a bonus you can test your C++ code from Python using these same SWIG interfaces.
I think the way to go is to write your service in C++ (I am assuming you did all the homework and there is a good reason you want to write in C++) and then front it using an RPC server. Use something like Thrift or Protobufs for a fast RPC implementation.
Now write your web frontend in the language of your choice - python would be mine - and make RPC calls to do all your heavy lifting.
POCO Remoting gives you a very simple way of creating web services in C++ by just annotating C++ class definitions with special comments and running a code generator over it. It's commercial, but delivered with full source code. A free eval version is available. Runs on Windows, Linux, Mac OS X, etc.
I concur with imjorge's answer and add that there's a C/C++ version of the Axis2 framework (a more flexible, extensible Axis) that does SOAP via RPC and all sorts of stuff including a bunch of the WS-* specs.
http://ws.apache.org/axis2/c/
Apache axis-c:
Simple to use, but seems abandoned.. not even download pages is working for several months
WSOF WSFCPP:
Fast quickstart dev, both binded or no-binded implementation, based on Apache AxisC and it seems most of the current developers of Apache Axis is from WSOF company. Besides the Great potential I've detected a memory leak.
I'm currently using Gsoap and It has very good performance.
Gsoap "mixed notation" between old c style and some (bad?) practices for C++ bothers me some.. but this is only code-furniture.
POCO:
Is a full-feature, modern (java?) like library. It is open source software, licensed under the Boost Software License 1.0. You'll have to write some things from scrach, but with great support, utility classes and etc great library.. Innovations from c++11+ with all boost initiatives + POCO + a new Build/Dependency system more "gradle like" will certainly bring c++ to new areas of development.