SOAP client in .NET - references or examples? [closed]

Question

Background:

I am creating a webservices site which will provide many types of simple services over SOAP and possibly other protocols too. The goal is to make it easy to do for example conversions, RSS parsing, spam checks and many other types of work. The site will be targeted mostly at beginner developers.

My Problem:

I have never developed any C#, or .NET for that matter. I did hack some VB6 many years ago but that's it. Now I need some examples of doing RPC calls over SOAP in C#. I have tried to search the web, and Stack Overflow, to find this but didn't find many resources, and I have no idea how to rank the resources (which are old? which are incorrect? etc).

I have created a simple example service, which is called like this in PHP:

<?php
$client = new SoapClient('http://webservi.se/year'); //URL to the WSDL
echo $client->getCurrentYear(); //This method returns an integer, called "year"
?>

I now want to call this method as easily as possible in C#. All references and examples are very welcome. Where do I begin? Which classes/modules/whatever can I utilize?

The solution does not have to involve SOAP at all if there are better communication frameworks (the back end is meant to be extensible), but note that the server side is implemented in PHP on Unix so proprietary solutions from Microsoft are out of the question on the server side.

Note that I need this so I can write documentation possible for J. Random Web Developer to follow (even if they are on shared web hosting). I therefore think the best approach should be to do this in code only, but even other ways of doing this are of course welcome.

Answer 1

Prerequisites: You already have the service and published WSDL file, and you want to call your web service from C# client application.

There are 2 main way of doing this:

A) ASP.NET services, which is old way of doing SOA
B) WCF, as John suggested, which is the latest framework from MS and provides many protocols, including open and MS proprietary ones.

Adding a service reference step by step

The simplest way is to generate proxy classes in C# application (this process is called adding service reference).

1. Open your project (or create a new one) in visual studio
2. Right click on the project (on the project and not the solution) in Solution Explorer and click Add Service Reference

3. A dialog should appear shown in screenshot below. Enter the url of your wsdl file and hit Ok. Note that if you'll receive error message after hitting ok, try removing ?wsdl part from url.

   

   I'm using http://www.dneonline.com/calculator.asmx?WSDL as an example

4. Expand Service References in Solution Explorer and double click CalculatorServiceReference (or whatever you named the named the service in the previous step).

   You should see generated proxy class name and namespace.

   In my case, the namespace is SoapClient.CalculatorServiceReference, the name of proxy class is CalculatorSoapClient. As I said above, class names may vary in your case.

   

5. Go to your C# source code and add the following

   using WindowsFormsApplication1.ServiceReference1
   

6. Now you can call the service this way.

   Service1Client service = new Service1Client();
   int year = service.getCurrentYear();
   

Hope this helps. If you encounter any problems, let us know.

Answer 2

I have done quite a bit of what you're talking about, and SOAP interoperability between platforms has one cardinal rule: CONTRACT FIRST. Do not derive your WSDL from code and then try to generate a client on a different platform. Anything more than "Hello World" type functions will very likely fail to generate code, fail to talk at runtime or (my favorite) fail to properly send or receive all of the data without raising an error.

That said, WSDL is complicated, nasty stuff and I avoid writing it from scratch whenever possible. Here are some guidelines for reliable interop of services (using Web References, WCF, Axis2/Java, WS02, Ruby, Python, whatever):

• Go ahead and do code-first to create your initial WSDL. Then, delete your code and re-generate the server class(es) from the WSDL. Almost every platform has a tool for this. This will show you what odd habits your particular platform has, and you can begin tweaking the WSDL to be simpler and more straightforward. Tweak, re-gen, repeat. You'll learn a lot this way, and it's portable knowledge.
• Stick to plain old language classes (POCO, POJO, etc.) for complex types. Do NOT use platform-specific constructs like List<> or DataTable. Even PHP associative arrays will appear to work but fail in ways that are difficult to debug across platforms.
• Stick to basic data types: bool, int, float, string, date(Time), and arrays. Odds are, the more particular you get about a data type, the less agile you'll be to new requirements over time. You do NOT want to change your WSDL if you can avoid it.
• One exception to the data types above - give yourself a NameValuePair mechanism of some kind. You wouldn't believe how many times a list of these things will save your bacon in terms of flexibility.
• Set a real namespace for your WSDL. It's not hard, but you might not believe how many web services I've seen in namespace "http://www.tempuri.org". Also, use a URN ("urn:com-myweb-servicename-v1", not a URL-based namespace ("http://servicename.myweb.com/v1". It's not a website, it's an abstract set of characters that defines a logical grouping. I've probably had a dozen people call me for support and say they went to the "website" and it didn't work.

</rant> :)