I have a library/API that is completely built with C/C++ for over 10 years (under Linux). Now I want to export the API as a web service for other web projects use. I search for the web and narrow down to the following 3 chooses:
use SWIG to export the API to PHP or other script/web base language
use gSOAP to export the API as SOAP protocol
export the API as RESTful service (I can't find any exist framework, any suggestions?)
I want to compare them in terms of
stability
easy of use
performance
SWIG seems easy to use buy I am not sure the stability of it.
gSOAP seems very stable but a bit difficult to use and setup.
Any suggestion?
I personally used WSO2-WSF-CPP which is a C++ layer on top of AXIS2/2 to export legacy C++ code as web-service.
I tried back then gSOAP which worked quite well, but for stability and deployment reasons I choose WSO2, since AXIS2/C can be deployed easily as a module of the well know Apache2 HTTP server.
For the ease of use requirement I don't know if you plan to take WSDL file as a template to generate source code skeleton, but you can forget about this feature of the WSO2 package ... It seems to have been deprecated for a long time and the generated code is way too ugly to be maintained by hand.
Although doing a code generator yourself could be a good idea depending on the complexity and the amount of services you have. I recommend it! I did that and creating/building/generating services is quite straightforward now.
Another thing to notice about the WSO2 web services is that it's simple to build out of the box, and comes with stand-alone server to develop and test with. It was quite helpful (even if I am quite sure any decent web-service platform provides this kind of stuff like gSOAP does).
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I am looking for the best way to add support for a REST based Web Service to an MFC C++ Application. This is legacy code that has been around a long time.
I need to have the Application provide the Web Service. I've researched this, and the articles are about consuming Web Services in a C++ App. I envision having to monitor a port and respond to the HTTP requests. It would probably make more sense to tie in with WCF and IIS, but I am not sure how to move forward.
I already have a tool of "making" this App into a Windows Service. I realize it would be better to have a "real" app, and this is what I have to work with. There is so much logic in this code and we are limited in development time, so we are taking the fastest approach possible. We also cannot use DCOM, as the Web Service will be called by a Linux based system.
Any suggested articles would be much appreciated.
For C++ you can test two libraries WSF/C and gSoap, another alternative is to develop it with C# and WCF , and communicate between C# and C++ using C++\CLI.
I use the Poco Net c++ library for this as it supports both HTTP client and server functionality. I considered various other libraries including Boost based stuff, but other than Poco I struggled to find everything I needed in one tidy package. It also has some easy to use mutex support which became essential for me as soon as I added a web server front-end to what had previously been a simple single threaded console app. Poco is cross platform but I mainly use it windows and it has served me well to date. I'm not very clued up on MFC so I don't know how it would get on in that department though.
One of our product publishes a webservice using contract-last approach. This has becoming a real problem as all of our clients (ws clients) have to rebuild their client apps as soon as we release a new version of our product. This is due to all namespace changes that comes as a cost with auto-generated wsdls. We use Axis1 for javatowsdl. I've been seeking for a good methodology/ tool to develop backward compatible webservice for this.
i.e. version 9.3 clients can still hit the 10.0 service, of cause they will miss some of the functionality, that is fine. But they should be able to function without breaking.
I do understand the whole problem is due to our contract last approach (Pls. correct me if I'm wrong). Therefore, if the solution is to go for contract-first webservice what are the tools and technologies I could use? Also what are the best practises around contract-first?
Thanks in advance.
As you already realized, the recommendation is to use a Contract-First (or Top-Down) approach to develop Web Services. That implies a manual definition of your WSDL interface and generate a Java Skeleton of the Web Service based on this document using automatic tools.
Is important that your WSDL complies to the WS-I standart to assure interoperability between clients on different platforms. You can use SOAP-UI to test whether your WSDL is compatible with the standard or not.
For the Skeleton generation, there are several Web Service Runtime API's that you can use: Like Apache Axis and JAX-WS. I personally prefer JAX-WS because is a Java Standard and is supported by all Java EE Containers. Each container provides tools for the Skeleton generation, Weblogic has some nice Ant Task for that but there's also WS-Import that is Container neutral.
We're looking at developing a Web Service to function as a basis for a browser display/gui for a networked security prototype written in C++. My experience with web services has been limited to Java. I prefer Web Services in Java because it's on the "beaten path".
One sure was to do this would be to simply code a Java client which invokes the web service, and call it as a command line with parameters from the C++ code.
It's not ideal, since generally speaking an API is preferable, but in this case it would work and be a pretty safe solution.
A resource which does handles web service development in C++ is called gSOAP, at this url: http://gsoap2.sourceforge.net
Any thought on which is a better approach? Has anyone used gSOAP, and if so, what did you think?
I'd done things with gSOAP, it's not awful. I'm increasingly opposed to the RPC model for web services, though; it forces you into a lot of connection and session state that adds complexity. A REST interface is simpler and more robust.
To me is Axis C++.
For RPC style, have a look at Thrift,
I found it quite better ( faster, clearer, a lot of languages implementations) than soap.
My colleague ended up using a combination of Axis2 / java (for the service) and gsoap for the client. He created the wsdl from the Java service by generating it from a C++ header (using c2wsdl (?) or something like that. He said it was better than using a Java interface because that generated two sets of wsdl, for seperate versions of soap.
Then he used wsdl2java to generate the webservice and a test web client. Once we got that working, he used gsoap to create the web client (in C++), and it worked fine.
thanks for all the answers! I ended using a combination of them.
I had very good experience with gsoap - very simple, performance is good.
If it is acceptable to run only on Windows, there is a brand-new API for that purpose: WWSAPI
Instead of calling the java client from the command line, you can create a java virtual machine inside your C app, instantiate the class and call any methods. This is what the java.exe app does and I think the source code is included in the jdk.
Depends on how low level you want to go. You might checkout yield.
I apologize if if this is a bonehead question.
I've used WSDL to generate code to talk to web services, but my question is about using it to actually generate web services.
Let's say that I have a device that is going to communicate with a web service. The web service in question doesn't actually exist and is out of my control. That is, the party wishing to process messages from my device must implement the service.
The service in this case is extremely basic. It's simply a small collection of methods that receive messages and return status codes. It's basically a middleman between my device and 3rd party software.
It would be really cool if I could supply something like a WSDL 2.0 document that they could then use to actually generate the boilerplate code for the service and methods they are required to implement...preferably in Java (Axis) and .NET friendly frameworks.
In other words, I want to use WSDL to generate the service, not the client. Or maybe I don't want WSDL at all. What techniques would you recommend to make this as painless as possible?
SvcUtil.exe for the Windows Communication Foundation technology in .NET 3.0+ can do some of what you're asking, i.e. generation of contract interfaces and basic client code using a predetermined WSDL as input.
Now, this will not fully generate the actual service, just the contract interface. I don't know of an easy way to do this as it is probably not a very common case. Essentially what you're asking is a slightly more automated version of what Visual Studio does when you create a class and use the "Implement interface" feature (which I believe is accomplished mostly through VS templates).
My gut feel is that document based web services are preferred in practice - is this other peoples experience? Are they easier to support? (I noted that SharePoint uses Any for the "document type" in its WSDL interface, I guess that makes it Document based).
Also - are people offering both WSDL and Rest type services now for the same functionality? WSDL is popular for code generation, but for front ends like PHP and Rails they seem to prefer rest.
Document versus RPC is only a question if you are using SOAP Web Services which require a service description (WSDL). RESTful web services do not not use WSDL because the service can't be described by it, and the feeling is that REST is simpler and easier to understand. Some people have proposed WADL as a way to describe REST services.
Languages like Python, Ruby and PHP make it easier to work with REST. the WSDL is used to generate C# code (a web service proxy) that can be easily called from a static language. This happens when you add a Service Reference or Web Reference in Visual Studio.
Whether you provide SOAP or REST services depends on your user population. Whether the services are to be used over the internet or just inside your organization affects your choice. SOAP may have some features (WS-* standards) that work well for B2B or internal use, but suck for an internet service.
Document/literal versus RPC for SOAP services are described on this IBM DevelopWorks article. Document/literal is generally considered the best to use in terms of interoperability (Java to .NET etc). As to whether it is easier to support, that depends on your circumstances. My personal view is that people tend to make this stuff more complicated than it needs to be, and REST's simpler approach is superior.
As mentioned it is better to choose the Document Literal over RPC encoded whenever possible.
It is true that the old java libraries (Axis1, Glue and other prehistoric stuff) support only RPC encoded, however in today's most modern Java SOAP libs just does not support it (e.x. AXIS2, XFire, CXF).
Therefore try to expose RPC encoded service only if you know that you need to deal with a consumer that can not do better. But then again maybe just XML RPC could help for these legacy implementations.
BiranLy's answer is excellent. I would just like to add that document-vs-RPC can come down to implementation issues as well. We have found Microsoft to be Document-preferring, while our Java-based libraries were RPC-based. Whatever you choose, make sure you know what other potential clients will assume as well.