Adding a web reference to your C# project and keeping it up to date, especially in times where many changes are being made, can be very tiresome. It occurred to me the other day that it must be possible to call a service on the fly in C# code using refection. Surely this functionality is included in the .Net framework. I was correct, it is, but it is not too well documented (Probably because it is slower at executing when compared with using a web reference – reflection etc…). However sometimes flexibility is more important than speed so I decided to look into implementing a solution.
Initially I had tired to read in the service’s WSDL via the ServiceDescription and parse it, however this proved to be very problematic and slow. Then in my travels around the many useless Google results I came across and Article on CodeProject.com by Ehsan Golkar. In this article Ehsan uses the ServiceDescription but loads the output into a ServiceDescriptionImporter. This then allows the creation of a compiled assembly into memory that will interface with the web service. Ehsan code seemed rather hard wired to his UI so I have taken the liberty to create a class that makes its operation much more generic.
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using System; using System.CodeDom; using System.CodeDom.Compiler; using System.Collections.Generic; using System.Linq; using System.Net; using System.IO; using System.Text; using System.Reflection; using System.Threading.Tasks; using System.Web.Services; using System.Web.Services.Description; using System.Xml.Serialization; namespace Core { /// <summary> /// Takes a WSDL file and allowes dynamic interaction with the service without a need for a web referance /// </summary> public class ServiceInspector { #region Varibles private Uri _serviceLocation; private List<MethodInfo> _methodInfo = new List<MethodInfo>(); private Type _service; #endregion #region Contructor /// <summary> /// Creates a new Service Inspector from a given Uri of a WSDL /// </summary> /// <param name="serviceLocation">The location of the services WSDL file</param> public ServiceInspector(Uri serviceLocation) { if (serviceLocation.Query == string.Empty) { UriBuilder uriB = new UriBuilder(serviceLocation); uriB.Query = "WSDL"; serviceLocation = uriB.Uri; } _serviceLocation = serviceLocation; WebRequest wsdlWebRequest = WebRequest.Create(serviceLocation); Stream wsdlRequestStream = wsdlWebRequest.GetResponse().GetResponseStream(); //Get the ServiceDescription from the WSDL file ServiceDescription sd = ServiceDescription.Read(wsdlRequestStream); string sdName = sd.Services[0].Name; ServiceDescriptionImporter sdImport = new ServiceDescriptionImporter(); sdImport.AddServiceDescription(sd, String.Empty, String.Empty); sdImport.ProtocolName = "Soap"; sdImport.CodeGenerationOptions = CodeGenerationOptions.GenerateProperties; CodeNamespace codeNameSpace = new CodeNamespace(); CodeCompileUnit codeCompileUnit = new CodeCompileUnit(); codeCompileUnit.Namespaces.Add(codeNameSpace); ServiceDescriptionImportWarnings warnings = sdImport.Import(codeNameSpace, codeCompileUnit); if (warnings == 0) { StringWriter stringWriter = new StringWriter(System.Globalization.CultureInfo.CurrentCulture); Microsoft.CSharp.CSharpCodeProvider prov = new Microsoft.CSharp.CSharpCodeProvider(); prov.GenerateCodeFromNamespace(codeNameSpace, stringWriter, new CodeGeneratorOptions()); //Compile the assembly string[] assemblyReferences = new string[2] { "System.Web.Services.dll", "System.Xml.dll" }; CompilerParameters param = new CompilerParameters(assemblyReferences); param.GenerateExecutable = false; param.GenerateInMemory = true; param.TreatWarningsAsErrors = false; param.WarningLevel = 4; CompilerResults results = new CompilerResults(new TempFileCollection()); results = prov.CompileAssemblyFromDom(param, codeCompileUnit); Assembly assembly = results.CompiledAssembly; _service = assembly.GetType(sdName); _methodInfo.Clear(); foreach (MethodInfo mi in _service.GetMethods()) { if (mi.Name == "Discover") { break; } _methodInfo.Add(mi); } } } #endregion #region Methods /// <summary> /// Gets a list of all of the methods on the service /// </summary> /// <returns>A list of all the methods</returns> public List<MethodInfo> GetMethods() { return _methodInfo; } /// <summary> /// Checks if the service has a specific method /// </summary> /// <param name="methodName">The name of the method</param> /// <param name="method">The MethodInfo of the method</param> /// <returns>True = Service contains method, False = Service does not contain method</returns> public bool HasMethod(string methodName, out MethodInfo method) { bool foundMethod = false; method = null; foreach (MethodInfo mi in _methodInfo) { if (mi.Name == methodName) { method = mi; foundMethod = true; break; } } return foundMethod; } /// <summary> /// Gets a list of the parameters of a give method /// </summary> /// <param name="methodName">The name of the method</param> /// <returns>A list of parameters for the given method</returns> public List<ParameterInfo> GetMethodParameters(string methodName) { MethodInfo method; if (HasMethod(methodName, out method)) { return method.GetParameters().ToList(); } return new List<ParameterInfo>(); } /// <summary> /// Runs a given method on the web service /// </summary> /// <param name="methodName">The name of the method</param> /// <param name="methodParameters">The parameters for the method</param> /// <returns>The object returned by the method</returns> public object RunMethod(string methodName, List<object> methodParameters) { object result = null; MethodInfo method; if (HasMethod(methodName, out method)) { List<ParameterInfo> paramList = method.GetParameters().ToList(); if (methodParameters.Count != paramList.Count) { throw new Exception("No method '" + methodName + "' which takes " + methodParameters.Count.ToString() + " parameters"); } List<object> paramsToPass = new List<object>(); int index = 0; foreach(ParameterInfo pi in paramList) { paramsToPass.Add(Convert.ChangeType(methodParameters[index], pi.ParameterType)); index++; } Object serviceInstance = Activator.CreateInstance(_service); return method.Invoke(serviceInstance, paramsToPass.ToArray()); } return result; } /// <summary> /// Runs a given method on the web service /// </summary> /// <param name="methodName">The name of the method</param> /// <param name="methodParameters">The parameters for the method</param> /// <param name="cc">The CookieContainer you wish to pass and recieve back</param> /// <returns>The object returned by the method</returns> public object RunMethod(string methodName, List<object> methodParameters, ref CookieContainer cc) { object result = null; MethodInfo method; if (HasMethod(methodName, out method)) { List<ParameterInfo> paramList = method.GetParameters().ToList(); if (methodParameters.Count != paramList.Count) { throw new Exception("No method '" + methodName + "' which takes " + methodParameters.Count.ToString() + " parameters"); } List<object> paramsToPass = new List<object>(); int index = 0; foreach (ParameterInfo pi in paramList) { paramsToPass.Add(Convert.ChangeType(methodParameters[index], pi.ParameterType)); index++; } Object serviceInstance = Activator.CreateInstance(_service); serviceInstance.GetType().GetProperty("CookieContainer").SetValue(serviceInstance, cc); object returnObj = method.Invoke(serviceInstance, paramsToPass.ToArray()); cc = (CookieContainer)serviceInstance.GetType().GetProperty("CookieContainer").GetValue(serviceInstance, null); return returnObj; } return result; } #endregion } } |
Here is my Visual Studio solution which includes a test web service and a win forms application with uses ServiceInspector to call the test web service.