Calling WCF from C code - c

I am working with a native C client application (not built with Visual Studio) that needs to call a WCF service. I am creating the WCF service, so I have complete control of it.
Most of the information I have found deal with calling WCF from unmanaged C++ clients.
Has anyone tried WWSAPI?
I am hoping to get some direction on whether this is even possible and what technologies can be used. Any help would be greatly appreciated!

you can use gSOAP is a technology that allows you to create stubs for client and server side code from WSDLs. Here is step by step tuttorial and that one for windows

WCF is very powerful and configurable and allows to use many different bindings (HTTP, Sockets, MSMQ, custom, etc.). Starting from version 3.5 I belive, you can use a JSON/REST bindings and contracts. Here is an official link about this: Overview of REST in WCF, and some samples here: WCF 4 JSON REST Service and here: REST Service with WCF and JSON.
Now, why REST and JSON? because these prococols are very lightweight and do not need huge dependencies or libraries. That was in fact the whole point of REST, as opposed to SOAP.
So, with these, you only need a TCP/HTTP stack and a JSON parser on the client-side wich makes it relatively easy to program in C. Here is a link to a simple JSON library: Jansson

Related

Calling MS Dynamics CRM SOAP Service using Angular JS

I am developing an ionic application which will interact with MS Dynamics CRM. I have looked online for solutions, but all solutions are either RESTful implementations or non MS Dynamics implementations. Has anyone implemented SOAP services of MS Dynamics using Angular JS? If possible please share example.
Several questions that probably will lead you to solution:
Do you have special requirements to use SOAP? Most of CRM functionality successfully exposed via REST / OData endpoints. Only for really none-trivial cases you would need to use SOAP syntax. You can check list of current limitations here. Consider using REST instead.
Another question would be, where your application is deployed? Is it within CRM itself? Or not? If Angular application is started within CRM (as WebResource) this is a lot simpler! Since you are already authorized to the service and you don't need to bother about that. In this case maybe this library could provide you some help... there are several approaches to create great middleware for SOAP requests to CRM, this seems to be most modern one.
But if you're not authorized... This is whole new level of the problem... Which environment you're targeting? OnLine? OnPrem?
In that case, first you need to authorize, then you can proceed with your queries, for example with the help of the library on previous step. There is one JS library that could help. It is abandoned, but you can take a look on the code. I'm talking about dynamicscrm-api. It won't work in browser, but it will give you understanding, how you can move on.

WCF - Launch Self Host Application on-demand

I am working on a project requiring communication between the Presentation layer (MVVM based client) and the Business layer. The application is to be installed on a single machine, and as such could have been executed using a .net remoting based approach. However, I have been suggested to use WCF since .net remoting is deprecated and WCF is the way to go.
So I implemented WCF Service as a WCF library project. I added a service reference (using visual studio tool by discovering services in the solution), which was successfully added on the client side. All works well, since during debug session visual studio launches the service library and the client can connect to it successfully.
Now Since the client and service host will be installed on same machine, I was thinking of using named pipes transport and self hosting for the WCF service. Here is where this gets very confusing to me:-
Since the MVVM client is the "main" app (since it is the application frontend), the client will be launched first. I am unable to come up with a solution to launch the service host "on-demand" when the client needs the same.
What are the solution I can use to do what I require for 1? I am not sure of using a continuous service through windows service for something that will be required "on-demand".
Please suggest clean approach to implement a way to launch "on-demand" service.
Thanks in advance.
I'm not quite following you here. MVVM is cake and really doesn't have anything to do with your problem. Using a servicebased architecture is a must today, I just want to smack every old guy/gal sticking to direct SQL on the client side, and don't see the dangers with that.
Well anyhow, you may solve this different ways. WCF is BIG, to big in my opinion. One way to use it, common on small applications like apps(WP8.1, 8.1 apps++), is just to connect, call the method you need and the close the connection. Case solved, given that I understand your needs. The otherway is to keep the session alive for each service... (ugh, loadbalancing etc).
I've been working on large LOB applications the last 4 years my self, what I can tell, is that if I were in charge, I would have done it very differently. For once I would used JSON endpoints with SSL over HTTP, and the json.net serializer. The datacontract serializer which is the default in WCF, is not good news at all. JSON allows easy communication with JavaScript based applications, and the serializer doesn't break like porcelain as the datacontract serializer does. Address/baseaddress may be stored in your config file, so it may be changed upon deployment(you probably have many servers, for different environments).
This is a really old post covering the subject(supporting SOAP aside JSON); REST / SOAP endpoints for a WCF service
Don't be stupid and just call your services directly now! Use the interface(Wrap if necessary) and feed it to your viewmodels for proper TDD! It will also allow you to completely replace WCF with another form of communication.
There also are alternatives to WCF.
IIS? Hosting WCF in IIS rather than a proper service? No way, flush that idea down the waterloo ;) (internal joke)
EDIT:
BTW: Your service must ofc already be running for your client to connect to it! Or nothing will be listening to your configured port. If you are selfhosting, you can use parameters to start in debug mode, that is start your service like a regular application you may debug. In Program.cs;
if (args.Length > 0 && String.Equals(args[0],"debugmode", StringComparison.OrdinalIgnoreCase)
{
Service1.Create(); // Debugging!
}
else
{
// Hosting
service = new Service1{ServiceName="YourService"};
ServiceBase.Run(new ServiceBase[] {service};);
}
Hope it helps,
Cheers,
Stian

How does a webapp save files to its server?

I'm building a webapp where one can develop documents within the web browser (e.g., something like Zoho's document tool, or Google Docs). In my case, I have a set of arrays that store different paragraphs and other pieces of information, along with parallel arrays that store metadata on the paragraphs themselves.
The entire webapp is written in jQuery and associated libraries / plugins.
Is there an elegant way for me to save this as a file on the server itself? So far, I've been recommended using a hidden form to POST the arrays to the server and store them in a NoSQL database of some sort... This feels a bit painful to me and I'm wondering if (1) there is a more elegant approach, or (2) there is a library / framework that automates some of the sending / POSTing / saving.
Thank you!
You would need to create services that live on the server itself. These services would be methods such as (just as a simple example)
SaveDocument(User, Document)
GetDocument(User, Document)
you would need to configure your web app to call these services and pass in the required parameters. Now as for how to do this, you could write the services in any number of languages (Java using JavaEE, C# using WCF to name a few, but you can also do this in python/ruby/etc) and then generate WSDL interfaces to the services that any number of other languages could call.
There are lots of resources available on the web that cover this, so pick a language you want to learn, or are already proficient in and google around on how to develop web services in that language.
Good luck!

Silverlight Data Access - how to keep the gruntwork on the server

What technologies are used / recommended for HTTP Rpc Calls from Silverlight. My Server Side stack is JBoss (servlets / json_rpc [jabsorb]), and we have a ton of business logic (object creation, validation, persistence, server side events) in place that I still want to take advantage of.
This is our first attempt at bringing an applet style ria to our product, and ideally we keep both HTML and Silverlight versions.
For better or worse the powers that be have pushed us down the silverlight path, and while flex / java fx / silverlight is an interesting debate, that question is removed from the equation. We just have to find a way to get silverlight to behave with our classes.
Should I be defining .NET Class representation of our JSON objects and the methodology to serialize / deserialize access to those objects? IE "blah.com/dispenseRpc?servlet=xxxx&p1=blah&p2=blahblah creating functions that invoke the web request and convert the incomming response string to objects?
Another way would be to reverse engineer the .NET wcf(or whatever) communications and implement the handler on the Java side that invokes the correct server side code and returns what .NET expects back. But that sounds much trickier.
T
Well since we are using JSON Rpc over HTTP on the server -> HTML clients, we decided to use HTTP calls and the .NET JsonSerializer; future plans are to add Java Annotations on our EJB project and a console applciation that will run against the EJB and generate the HTTP calls and F# Records with the DataContract attributes.
It is working pretty smoothly. Had some issues with async in silverlight, but got it working with some aid from the folks at MS.
Thx

How to wrap a C library so that it can be called from a web service

We have a library with very complex logic implemented in C. It has a command line interface with not too complex string-based arguments. In order to access this, we would like to wrap the library so that it can be accessed with simple XML RPC or even straightforward HTTP POST calls.
Having some experience with Java, my first idea would be
Wrap the library in JNI/JNA
Use a thin WS stack and a servlet engine
Proxy requests through Apache to the servlet engine
I believe there should already be something simple that could be used, so I am posting this question here. A solution has the following requirements
It should be deployable to a current linux distribution, preferrably already available via package management
It should integrate with a standard web server (as in my example Apache)
Small changes to the library's interface should be manageable
End-to-end (HTTP-WS-library-WS-HTTP) the solution should not incur too much overhead, but reliability is very important
Alternatively to the JNI/JNA proposal, I think in the C# world it should not be too difficult to write a web service and call this unmanaged code module, but I hope someone can give me some pointers that are feasible in regards to the requirements.
If you're going with web services, perhaps Soaplab would be useful. It's basically a tool to wrap existing command line applications in SOAP web services. The web services it generates look a bit weird but it is quite a popular way to make something like this work.
Creating an apache module is quite easy and since your familiar with xmlrpc you should check out mod-xmlrpc2. You can easily add your C code to this apache module and have a running xmlrpc server in minutes
I think you may also publish it as a SOAP based web service. gSoap can be used to provide the service interface out of the library. Have you explored gSOAP? See http://www.cs.fsu.edu/~engelen/soap.html
Regards,
Kangkan
Depends what technology you're comfortable with, what you already have installed and working on your servers, and what your load requirements are.
How about raw CGI? Assuming the C code is stateless between requests, you can do this without modifying the library at all. Write a simple script which pulls the request parameters out of the CGI environment, perhaps sanitises the input, calls the library via the command-line interface, and packages the result into whatever HTTP response you want. Then configure Apache to dispatch the relevant URL(s) to this script. Python, for example, has library support for XML-RPC, and so does every other scripting language used on the web.
Servlets sound like overkill, but for instance if you want multiple requests per CGI process instantiation, and don't feel like getting involved in Apache configuration, then it might be easiest to stick with what you know.
I'm doing a similar thing with C++ at the moment. In my case, I'm writing a PHP module to allow PHP scripts to access the logic in my C++ library.
I can then use whatever format I want to allow the rest of the world to see it - initially it will just be through a PHP web application but I'll also be developing an XML-RPC interface.
If you're going down the JNI route, check out SWIG.
http://www.swig.org/Doc1.3/Java.html
Assuming you have headers to project bindings with, swig is pretty easy to work with.

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