A bit about the stuff I've done


Friday, 14 September 2012

Ajaxable Web Control in a Class Library

So I recently went on a course to get my AJAX knowledge up to scratch.
The course was fine and taught me quite a bit that I didn't know but the most important thing for me was missing - how do you do all this in a class library?

Basically I want the ability to have some control which has both server and client side components, for these 2 parts to talk to eachother with ajax, and I want to be able to wrap the whole thing up into a DLL file that can be dropped into any web application and with no user modifications required.

The instructor gave me this link which was helpful but didn't go the whole way.
I knew there had to be a better, more complete way, and so I set to work.

The result is what you see below.

Add the C# code in the block below to a class library and inherit from it for your server control.
You'll need a WebService and you'll have to provide that as the type parameter to the base class.
And that's about it!
The class does require some tweaking to the web.config file - but it will do that for you the first time you run it.

Here you can find the compiled DLL: http://dev.dj-djl.com/AjaxableServerControlWithWebService.zip
And a Template project for Visual Studio 2012: dev.dj-djl.com/AjaxableServerControlWithWebServiceTemplate.zip
The template control contains a single web-exposed method which is triggered when the button is clicked and the result is given to a simple alert box.

The code below contains some code taken from this Code Project post, which was modified by me.
The rest of the code is written by me. It is all licecned under an LGPL3.0 licence.   /* LGPL3.0 Classes enabling embedding of a fully AJAXable ASPX Server Control into a DLL for reuse or redistribution. Most of the code below is LGPL3.0 - Copyright (C) 2012 Lee Smith http://dev.dj-djl.com http://blog.dj-djl.com Contains some LGPL3.0 code As indicated - (C) 2007 James Ashley http://www.codeproject.com/Articles/22384/ASP-NET-AJAX-Controls-and-Extenders#http_handler LGPL3.0: This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not please see <http://www.gnu.org/licenses/>. */ using System; using System.Collections.Generic; using System.Reflection; using System.Text; using System.Web; using System.Web.Services; using System.Web.SessionState; using System.Web.UI; namespace DJL { internal static class Utils { public static string ToDelimitedstring<T>(this List<T> lst, string Delimiter = ",") { System.Text.StringBuilder sbReturn = new StringBuilder(); Boolean flgFirst = true; foreach (T Item in lst) { if (!flgFirst) { sbReturn.Append(Delimiter); } sbReturn.Append(Item.ToString()); flgFirst = false; } return sbReturn.ToString(); } public static string CompressAndBase64(string Value) { System.IO.MemoryStream mst = new System.IO.MemoryStream(); System.IO.Compression.GZipStream gz = new System.IO.Compression.GZipStream(mst, System.IO.Compression.CompressionLevel.Optimal, true); byte[] bytValue = System.Text.Encoding.UTF8.GetBytes(Value); gz.Write(bytValue,0 , bytValue.Length); gz.Flush(); gz.Close(); return Convert.ToBase64String(mst.ToArray()).Replace("+", "_").Replace("/", "-"); } public static string DeBase64AndDecompress(string Base64Value) { //return System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(Base64Value)); byte[] bytValue = Convert.FromBase64String(Base64Value.Replace("-", "/").Replace("_", "+")); System.IO.MemoryStream mst = new System.IO.MemoryStream(); System.IO.Compression.GZipStream gz =null; try { mst.Write(bytValue, 0, bytValue.Length); mst.Seek(0, System.IO.SeekOrigin.Begin); gz = new System.IO.Compression.GZipStream(mst, System.IO.Compression.CompressionMode.Decompress, false); byte[] bytDecompressedValue = new byte[102400]; //100k - should be enough! return System.Text.Encoding.UTF8.GetString(bytDecompressedValue, 0, gz.Read(bytDecompressedValue, 0, 102400)); } finally { gz.Close(); mst.Close(); } } public static string GetURLWithoutAsmx(Type type) { //System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create(); //byte[] bytTypeName = System.Text.Encoding.UTF8.GetBytes(type.Assembly.FullName + "/" + type.FullName); //return typeof(AjaxableScriptContolWithWebserviceHandlerFactory).Name + "/" + Convert.ToBase64String(md5.ComputeHash(bytTypeName)); return typeof(AjaxableScriptContolWithWebserviceHandlerFactory).Name + "/" + CompressAndBase64(type.Assembly.FullName + "/" + type.FullName); } public static string GetURLWithoutAsmx<T>() { return GetURLWithoutAsmx(typeof(T)); } } /// <summary> /// A serverside control which can be included into a DLL, with full ajax. /// It uses a webservice embedded into the same DLL to perform ajax operations. /// </summary> /// <typeparam name="TService">The type of the Webservice</typeparam> public abstract class AjaxableScriptContolWithWebservice<TService> : ScriptControl where TService : System.Web.Services.WebService { private bool flgConfigChanged = false; /// <summary> /// When set indicates that the web.config file was altered /// </summary> protected bool ConfigChanged { get { return flgConfigChanged; } } public AjaxableScriptContolWithWebservice() { CheckConfig(); this.Load += AjaxableScriptContolWithWebservice_Load; } private void CheckConfig() { //System.Configuration blah = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~"); System.Configuration.Configuration WebConfig = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~"); System.Xml.XmlDocument xmdWebConfig = new System.Xml.XmlDocument(); xmdWebConfig.Load(WebConfig.FilePath); if (System.Web.HttpRuntime.UsingIntegratedPipeline) { SetIntegratedConfig(xmdWebConfig, WebConfig.FilePath); } else { SetClassicConfig(xmdWebConfig, WebConfig.FilePath); } } private void SetIntegratedConfig(System.Xml.XmlDocument WebConfig, string WebConfigPath) { /* <system.webServer> <handlers> <add name="AjaxServerControl1.ServerControl1" verb="*" path="AjaxServerControl1.ServerControl1.asmx" type="AjaxServerControl1.ServerControl1" /> </handlers> </system.webServer> */ System.Xml.XmlElement xmeSystemWeb = (System.Xml.XmlElement)WebConfig.SelectSingleNode("/configuration/system.webServer"); if (xmeSystemWeb == null) { xmeSystemWeb = WebConfig.CreateElement("system.webServer"); WebConfig.DocumentElement.AppendChild(xmeSystemWeb); } System.Xml.XmlElement xmeHandlers = (System.Xml.XmlElement)xmeSystemWeb.SelectSingleNode("handlers"); if (xmeHandlers == null) { xmeHandlers = WebConfig.CreateElement("handlers"); xmeSystemWeb.AppendChild(xmeHandlers); } string strURL = Utils.GetURLWithoutAsmx<TService>(); System.Xml.XmlElement xmeAdd = (System.Xml.XmlElement)xmeHandlers.SelectSingleNode("add[@name='" + strURL + "']"); if (xmeAdd == null) { xmeAdd = WebConfig.CreateElement("add"); xmeAdd.SetAttribute("verb", "*"); xmeAdd.SetAttribute("name", strURL); xmeAdd.SetAttribute("path", strURL + ".asmx"); xmeAdd.SetAttribute("type", typeof(AjaxableScriptContolWithWebserviceHandlerFactory).FullName); xmeHandlers.AppendChild(xmeAdd); WebConfig.Save(WebConfigPath); flgConfigChanged = true; } } private void SetClassicConfig(System.Xml.XmlDocument WebConfig, string WebConfigPath) { throw new Exception(); /* <system.web> <httpHandlers> <add verb="*" path="AjaxServerControl1.ServerControl1.asmx" type="AjaxServerControl1.ServerControl1" validate="true" /> </httpHandlers> </system.web> * */ System.Xml.XmlElement xmeSystemWeb = (System.Xml.XmlElement)WebConfig.SelectSingleNode("/configuration/system.web"); if (xmeSystemWeb == null) { xmeSystemWeb = WebConfig.CreateElement("system.web"); WebConfig.DocumentElement.AppendChild(xmeSystemWeb); } System.Xml.XmlElement xmeHTTPHandlers = (System.Xml.XmlElement)xmeSystemWeb.SelectSingleNode("httpHandlers"); if (xmeHTTPHandlers == null) { xmeHTTPHandlers = WebConfig.CreateElement("httpHandlers"); xmeSystemWeb.AppendChild(xmeHTTPHandlers); } string strURL = Utils.GetURLWithoutAsmx<TService>(); System.Xml.XmlElement xmeAdd = (System.Xml.XmlElement)xmeHTTPHandlers.SelectSingleNode("add[@path='" + strURL + ".asmx']"); if (xmeAdd == null) { xmeAdd = WebConfig.CreateElement("add"); xmeAdd.SetAttribute("verb", "*"); xmeAdd.SetAttribute("path", strURL + ".asmx"); xmeAdd.SetAttribute("type", typeof(AjaxableScriptContolWithWebserviceHandlerFactory).FullName); xmeAdd.SetAttribute("validate", "true"); xmeHTTPHandlers.AppendChild(xmeAdd); WebConfig.Save(WebConfigPath); flgConfigChanged = true; } } protected bool AutoRefreshOnConfigChange { get; set; } protected override sealed void Render(HtmlTextWriter writer) { base.Render(writer); if (ConfigChanged && AutoRefreshOnConfigChange) { writer.WriteLine("<div style='position: fixed; height: 100%; width: 100%; top: 0; left: 0; background-color: rgba(128,128,128,0.85);'>\n" + " <div style='width: 40em; height: 5em; background-color: white; color: black; box-shadow: 2px 2px 0px black; text-align: center;" + "position: absolute; left: 50%; top: 50%; margin-left: -20em; margin-top: -2.5em;'><br/>" + "The web.config was updated. The page will now be reloaded.<br/>\n" + " N.B. You may have to check out the web.config file if it is under source control</div>\n" + "</div>"); writer.WriteLine("<meta http-equiv='refresh' content='1;" + this.Page.Request.Url.ToString() + "'/>"); } else { RenderContent(writer); } } protected virtual void RenderContent(HtmlTextWriter writer) { } void AjaxableScriptContolWithWebservice_Load(object sender, EventArgs e) { string strURL = Utils.GetURLWithoutAsmx<TService>(); ScriptManager.GetCurrent(this.Page).Services.Add(new ServiceReference(strURL + ".asmx")); } } // This class is largely written by James Ashley with some modifications by Lee Smith as indicated // see http://www.codeproject.com/Articles/22384/ASP-NET-AJAX-Controls-and-Extenders#http_handler for the original source code public class AjaxableScriptContolWithWebserviceHandlerFactory : IHttpHandlerFactory { #region IHttpHandlerFactory Members IHttpHandlerFactory factory = null; public IHttpHandler GetHandler(HttpContext context, string requestType, string url, string pathTranslated) { Assembly ajaxAssembly = typeof(System.Web.Script.Services.GenerateScriptTypeAttribute).Assembly; factory = (IHttpHandlerFactory)System.Activator.CreateInstance(ajaxAssembly.GetType("System.Web.Script.Services.RestHandlerFactory")); IHttpHandler restHandler = (IHttpHandler)System.Activator.CreateInstance(ajaxAssembly.GetType("System.Web.Script.Services.RestHandler")); ConstructorInfo WebServiceDataConstructor = ajaxAssembly.GetType("System.Web.Script.Services.WebServiceData").GetConstructor( BindingFlags.NonPublic | BindingFlags.Instance, null, new Type[] { typeof(Type), typeof(bool) }, null); MethodInfo CreateHandlerMethod = restHandler.GetType().GetMethod("CreateHandler", BindingFlags.NonPublic | BindingFlags.Static, null, new Type[] { ajaxAssembly.GetType("System.Web.Script.Services.WebServiceData"), typeof(string) }, null); IHttpHandler originalHandler = null; //LS Change the behvaiour for some URLs, original code contained some hard-coded assumptions and also did not provide the js and jsdebug methods. string strAssemblyName = context.Request.Url.Segments[2].Trim('/').Trim(); if (strAssemblyName.ToLower().EndsWith(".asmx")) { strAssemblyName = strAssemblyName.Substring(0, strAssemblyName.Length - 5); } strAssemblyName = Utils.DeBase64AndDecompress(strAssemblyName); string strTypeName = strAssemblyName.Split('/')[1].Trim(); strAssemblyName = strAssemblyName.Split('.')[0].Trim(); string strMethodName = context.Request.Url.Segments[3]; Assembly assAssembly = Assembly.Load(strAssemblyName); Type typWebServiceType = assAssembly.GetType(strTypeName); if (strMethodName == "js" || strMethodName == "jsdebug") { originalHandler = new WebserviceJSGenerator(typWebServiceType); } else { //LS End modifications originalHandler = (IHttpHandler)CreateHandlerMethod.Invoke(restHandler, new Object[]{ WebServiceDataConstructor.Invoke(new object[] { typWebServiceType, false }), strMethodName }); } //<-- LS Type t = ajaxAssembly.GetType("System.Web.Script.Services.ScriptHandlerFactory"); Type wrapperType = null; if (originalHandler is IRequiresSessionState) { wrapperType = t.GetNestedType("HandlerWrapperWithSession", BindingFlags.NonPublic | BindingFlags.Instance); } else { wrapperType = t.GetNestedType("HandlerWrapper", BindingFlags.NonPublic | BindingFlags.Instance); } return (IHttpHandler)System.Activator.CreateInstance(wrapperType, BindingFlags.NonPublic | BindingFlags.Instance, null, new object[] { originalHandler, factory }, null); } public void ReleaseHandler(IHttpHandler handler) { factory.ReleaseHandler(handler); } #endregion } public class WebserviceJSGenerator : IHttpHandler { public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { if (context == null) { throw new ArgumentNullException("context"); } string clientProxyScript = GetClientProxyScript(type); if (clientProxyScript != null) { context.Response.ContentType = "application/x-javascript"; context.Response.Write(clientProxyScript); } } private string GetClientProxyScript(Type Type) { StringBuilder strScript = new StringBuilder(); strScript.AppendLine("// Generated by " + this.GetType().FullName); strScript.AppendLine("// http://dev.dj-djl.com"); strScript.AppendLine("// http://blog.dj-djl.com"); strScript.AppendLine("// loosely based on the code generated by Microsoft's System.Web.Script.Services.ClientProxyGenerator class"); strScript.AppendLine("// requires other Microsoft javascript libraries to be loaded and assumes that to be the case."); strScript.AppendLine("Type.registerNamespace('" + Type.Namespace + "');"); strScript.AppendLine(Type.FullName.Replace("+", "_") + "=function(){"); strScript.AppendLine(Type.FullName.Replace("+", "_") + ".initializeBase(this);"); strScript.AppendLine(" this._timeout=0,"); strScript.AppendLine(" this._userContext=null,"); strScript.AppendLine(" this._succeeded=null,"); strScript.AppendLine(" this._failed=null}"); strScript.AppendLine(Type.FullName.Replace("+", "_") + ".prototype={"); strScript.AppendLine(" _get_path:function(){"); strScript.AppendLine(" var p = this.get_path();"); strScript.AppendLine(" if (p) return p;"); strScript.AppendLine(" else return " + Type.FullName.Replace("+", "_") + "._staticInstance.get_path();"); strScript.AppendLine(" }"); foreach (System.Reflection.MethodInfo miMethod in Type.GetMethods(BindingFlags.Public | BindingFlags.Instance)) { if (miMethod.GetCustomAttributes(typeof(WebMethodAttribute), true).Length > 0) { strScript.Append(" ," + miMethod.Name + ":function("); List<string> lstParametersObject = new List<string>(); List<string> lstParametersXmlComments = new List<string>(); List<string> lstParametersJSFunction = new List<string>(); foreach (System.Reflection.ParameterInfo piParam in miMethod.GetParameters()) { if (!piParam.IsRetval) { lstParametersObject.Add(piParam.Name + ":" + piParam.Name); lstParametersXmlComments.Add(" /// <param name=\"" + piParam.Name + "\" type=\"" + piParam.ParameterType.Name + "\" optional=\"" + (piParam.IsOptional ? "true" : "false") + "\" mayBeNull=\"" + (piParam.ParameterType.IsValueType ? "true" : "false") + "\"></param>"); lstParametersJSFunction.Add(piParam.Name); } } if (lstParametersJSFunction.Count > 0) { lstParametersJSFunction.Add(""); }; //add a blank parameter so that we do infact get a trailing comma, but only if there are items strScript.AppendLine(lstParametersJSFunction.ToDelimitedstring(", ") + "succeededCallback, failedCallback, userContext) {"); strScript.AppendLine(lstParametersXmlComments.ToDelimitedstring("\n")); strScript.AppendLine(" /// <param name=\"succeededCallback\" type=\"Function\" optional=\"true\" mayBeNull=\"true\"></param>"); strScript.AppendLine(" /// <param name=\"failedCallback\" type=\"Function\" optional=\"true\" mayBeNull=\"true\"></param>"); strScript.AppendLine(" /// <param name=\"userContext\" optional=\"true\" mayBeNull=\"true\"></param>"); strScript.Append(" return this._invoke(this.get_path(), '" + miMethod.Name + "', false, {"); strScript.Append(lstParametersObject.ToDelimitedstring(", ")); strScript.AppendLine("}, succeededCallback,failedCallback,userContext);} "); } } strScript.AppendLine(" }"); string strStatic = @" <<TypeName>>.registerClass('<<TypeName>>',Sys.Net.WebServiceProxy); <<TypeName>>._staticInstance = new <<TypeName>>(); <<TypeName>>.set_path = function(value) { <<TypeName>>._staticInstance.set_path(value); } <<TypeName>>.get_path = function() { /// <value type=""String"" mayBeNull=""true"">The service url.</value> return <<TypeName>>._staticInstance.get_path();} <<TypeName>>.set_timeout = function(value) { <<TypeName>>._staticInstance.set_timeout(value); } <<TypeName>>.get_timeout = function() { /// <value type=""Number"">The service timeout.</value> return <<TypeName>>._staticInstance.get_timeout(); } <<TypeName>>.set_defaultUserContext = function(value) { <<TypeName>>._staticInstance.set_defaultUserContext(value); } <<TypeName>>.get_defaultUserContext = function() { /// <value mayBeNull=""true"">The service default user context.</value> return <<TypeName>>._staticInstance.get_defaultUserContext(); } <<TypeName>>.set_defaultSucceededCallback = function(value) { <<TypeName>>._staticInstance.set_defaultSucceededCallback(value); } <<TypeName>>.get_defaultSucceededCallback = function() { /// <value type=""Function"" mayBeNull=""true"">The service default succeeded callback.</value> return <<TypeName>>._staticInstance.get_defaultSucceededCallback(); } <<TypeName>>.set_defaultFailedCallback = function(value) { <<TypeName>>._staticInstance.set_defaultFailedCallback(value); } <<TypeName>>.get_defaultFailedCallback = function() { /// <value type=""Function"" mayBeNull=""true"">The service default failed callback.</value> return <<TypeName>>._staticInstance.get_defaultFailedCallback(); } <<TypeName>>.set_enableJsonp = function(value) { <<TypeName>>._staticInstance.set_enableJsonp(value); } <<TypeName>>.get_enableJsonp = function() { /// <value type=""Boolean"">Specifies whether the service supports JSONP for cross domain calling.</value> return <<TypeName>>._staticInstance.get_enableJsonp(); } <<TypeName>>.set_jsonpCallbackParameter = function(value) { <<TypeName>>._staticInstance.set_jsonpCallbackParameter(value); } <<TypeName>>.get_jsonpCallbackParameter = function() { /// <value type=""String"">Specifies the parameter name that contains the callback function name for a JSONP request.</value> return <<TypeName>>._staticInstance.get_jsonpCallbackParameter(); } <<TypeName>>.set_path(""/<<URL>>""); "; string strURL = Utils.GetURLWithoutAsmx(Type); strScript.AppendLine(strStatic.Replace("<<NameSpace>>", Type.Namespace).Replace("<<TypeName>>", Type.FullName.Replace("+", "_")).Replace("<<URL>>", strURL + ".asmx")); foreach (System.Reflection.MethodInfo miMethod in Type.GetMethods(BindingFlags.Public | BindingFlags.Instance)) { if (miMethod.GetCustomAttributes(typeof(WebMethodAttribute), true).Length > 0) { List<string> lstParametersJSFunction = new List<string>(); List<string> lstParametersXmlComments = new List<string>(); foreach (System.Reflection.ParameterInfo piParam in miMethod.GetParameters()) { if (!piParam.IsRetval) { lstParametersJSFunction.Add(piParam.Name); lstParametersXmlComments.Add(" /// <param name=\"" + piParam.Name + "\" type=\"" + piParam.ParameterType.Name + "\" optional=\"" + (piParam.IsOptional ? "true" : "false") + "\" mayBeNull=\"" + (piParam.ParameterType.IsValueType ? "true" : "false") + "\"></param>"); } } if (lstParametersJSFunction.Count > 0) { lstParametersJSFunction.Add(""); } string strMethodStatic = @" <<TypeName>>.<<MethodName>>= function(" + lstParametersJSFunction.ToDelimitedstring(", ") + @"onSuccess,onFailed,userContext) { " + lstParametersXmlComments.ToDelimitedstring("\n") + @" /// <param name=""succeededCallback"" type=""Function"" optional=""true"" mayBeNull=""true""></param> /// <param name=""failedCallback"" type=""Function"" optional=""true"" mayBeNull=""true""></param> /// <param name=""userContext"" optional=""true"" mayBeNull=""true""></param> <<TypeName>>._staticInstance.<<MethodName>>(" + lstParametersJSFunction.ToDelimitedstring(", ") + @" onSuccess,onFailed,userContext); }"; strScript.AppendLine(strMethodStatic.Replace("<<NameSpace>>", Type.Namespace).Replace("<<TypeName>>", Type.FullName.Replace("+", "_")).Replace("<<MethodName>>", miMethod.Name)); } } return strScript.ToString(); } Type type; public WebserviceJSGenerator(Type type) { this.type = type; } } }  

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