SOAP

SOAP (Simple Object Access Protocol) is a protocol for exchanging structured information in web services using XML. It is known for its robustness and extensibility.

1. Platform Independence: SOAP messages can be transported over a variety of network protocols, making it highly versatile.

2. Extensibility: SOAP is highly extensible through its support for protocols such as WS-Security, WS-AtomicTransaction, and more.

3. Standardized: SOAP is a well-defined protocol with standards established by the W3C.

4. Robust Error Handling: SOAP provides detailed error information through its fault elements.

5. Security: SOAP has built-in support for web services security (WS-Security), making it suitable for secure transactions.

Common Use Cases for SOAP XML

1. Enterprise Systems

   • Complex Transactions: Used in financial services, healthcare, and other sectors requiring complex transactions and security.

2. Asynchronous Processing

   • Queue Services: SOAP is well-suited for systems that require reliable messaging and asynchronous processing.

3. Legacy Systems

   • Integration: Often used to integrate with older legacy systems that require robust communication protocols.

SOAP XML Structure

A SOAP message consists of an envelope, header, and body, enclosed in XML tags.

<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
  <soap:Header/>
  <soap:Body>
    <m:GetPrice xmlns:m="http://www.example.org/stock">
      <m:StockName>IBM</m:StockName>
    </m:GetPrice>
  </soap:Body>
</soap:Envelope>

Creating and Consuming a SOAP API with ASP.NET Core and Console Application

Creating a SOAP API

1. Create a New ASP.NET Core Web API Project

dotnet new webapi -n SoapApiExample
cd SoapApiExample

2. Add SoapCore Package

Add the SoapCore package to your project:

dotnet add package SoapCore

3. Define the Service Contract

Create an interface for the SOAP service.

IStockService.cs

using System.ServiceModel;
using System.Threading.Tasks;

[ServiceContract]
public interface IStockService
{
    [OperationContract]
    Task<string> GetPriceAsync(string stockName);
}

4. Implement the Service

Create a class that implements the service.

StockService.cs

using System.Threading.Tasks;

public class StockService : IStockService
{
    public async Task<string> GetPriceAsync(string stockName)
    {
        // Simulate fetching the stock price
        await Task.Delay(100); // Simulate async operation
        return $"The price of {stockName} is $123.45";
    }
}

5. Configure the Service

Update the Program.cs file to configure the SOAP service.

Program.cs

using SoapCore;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSingleton<IStockService, StockService>();
builder.Services.AddSoapCore();
builder.Services.AddMvc();

var app = builder.Build();

app.UseRouting();
app.UseEndpoints(endpoints =>
{
    endpoints.MapControllers();
    endpoints.UseSoapEndpoint<IStockService>("/StockService.asmx", new SoapEncoderOptions());
});

app.Run();

6. Run the SOAP API

Run your API using the following command:

dotnet run

Test the API

You can test the API by navigating to https://localhost:5001/StockService.asmx (or the appropriate URL shown in your console). The SOAP endpoint should be available.

Calling the SOAP API from a Console Application

1. Create a New Console Application

dotnet new console -n SoapClientExample
cd SoapClientExample

2. Add WCF Services

Add the WCF package to your project:

dotnet add package System.ServiceModel.Http

3. Create a Service Contract

IStockService.cs

using System.ServiceModel;
using System.Threading.Tasks;

[ServiceContract]
public interface IStockService
{
    [OperationContract]
    Task<string> GetPriceAsync(string stockName);
}

4. Implement the SOAP Client

Program.cs

using System;
using System.ServiceModel;
using System.Threading.Tasks;

var endpointAddress = new EndpointAddress("https://localhost:5001/StockService.asmx");
var binding = new BasicHttpBinding();

var channelFactory = new ChannelFactory<IStockService>(binding, endpointAddress);
var client = channelFactory.CreateChannel();

var stockName = "IBM";
var price = await client.GetPriceAsync(stockName);
Console.WriteLine($"The price of {stockName} is {price}");

5. Run the Client Application

dotnet run

Output

The price of IBM is $123.45