Category: Asp.Net

Libwww-perl (LWP) is a WWW client/server library for perl which can be used by hackers, spammers or automated bots to attack a website to steal information so we need to apply security to our web application to eliminate many simpler attacks on the website. In order to fix this issue in an ASP.NET web application we can use the following code. Add the code in Application_BeginRequest method of Global.asax file in your web application protected void Application_BeginRequest(object sender, EventArgs e) { string userAgent = HttpContext.Current.Request.ServerVariables[“HTTP_USER_AGENT”]; if (!string.IsNullOrEmpty(userAgent)) { if (“Libwww-perl”.ToLower().Equals(userAgent.ToLower())) { Send403(Response); } } } internal void Send403(HttpResponse response) { SendResponse(response, 0x193, “403 FORBIDDEN”); } internal void SendResponse(HttpResponse response, int code, string strBody) { HttpContext current = HttpContext.Current; object obj2 = current.Items[“ResponseEnded”]; if ((obj2 == null) || !((bool)obj2)) { current.Items[“ResponseEnded”] = true; response.StatusCode = code; response.Clear(); if (strBody != null) { response.Write(strBody); } response.End(); } } Another option is to disallow Libwww-perl user[…]

Search engines treat website URL with and without “www” differently. Though both URLs point to the same destination, it’s important to pick one and set as your preferred URL so that search engines don’t two URLs as duplicate content. Websites use 301 redirect for this. The example code to redirect non-www URL to www URL in an ASP.NET application would be as following. Add following code snippet in Application_BeginRequest method of your Global.asax. Replace URL (somewebsite.com) with your website URL in the code and you are all set. protected void Application_BeginRequest(object sender, EventArgs e) { if (HttpContext.Current.Request.Url.AbsoluteUri.ToLower().StartsWith(“http://somewebsite.com”)) { string newUrl = HttpContext.Current.Request.Url.AbsoluteUri.ToLower().Replace(“http://somewebsite.com”, “http://www.somewebsite.com”); Response.Status = “301 Moved Permanently”; Response.AddHeader(“Location”, newUrl); } } If you want to do the opposite and direct www URL to non-www URL simply change the code as following protected void Application_BeginRequest(object sender, EventArgs e) { if (HttpContext.Current.Request.Url.AbsoluteUri.ToLower().StartsWith(“http://www.somewebsite.com”)) { string newUrl = HttpContext.Current.Request.Url.AbsoluteUri.ToLower().Replace(“http://www.somewebsite.com”, “http://somewebsite.com”); Response.Status = “301 Moved Permanently”;[…]

It’s very important for a web site to create SEO friendly URL’s and remove page extensions such as .aspx. When search engines look at a site, the first thing they analyze is the page URL which help them ascertain what the page content is about. In ASP.NET application Routes can be used for this which are URL patterns used for processing requests and can be used to construct URLs dynamically. The Global.asax file is a special file that contains event handlers for ASP.NET application lifecycle events. The route table is created during the Application Start event in Global.asax. In order to do so add Global Application Class (Global.asax) to your ASP.NET Web Application if it is not created yet. The following example shows how to add a route. protected void Application_Start(object sender, EventArgs e) { try { RegisterRoutes(RouteTable.Routes); } catch (Exception ex) { // Log Exception here } } protected static void RegisterRoutes(RouteCollection routes) { if[…]

If you create a ASP.ENT website using Visual Studio 2015 or higher and .NET Framework 4.5.2, it by default uses Roslyn which is a set of open-source compilers and code analysis APIs for C# and Visual Basic. Publishing this would also include “roslyn” folder in bin directory containing a bunch of libraries and exe files which creates issues if you are using a shared hosting service as normally shared hosting do not run under full trust. We can simply remove this by going to Tools -> NuGet Package Manager -> Manager NuGet Packages for Solution -> Uninstall following packages Microsoft.CodeDom.Providers.DotNetCompilerPlatform Microsoft.Net.Compilers Check web.config and make sure the following section was removed by the NuGet package uninstall. If it did not get removed for any reason, then clean it up manually <system.codedom> <compilers> <compiler language=”c#;cs;csharp” extension=”.cs” type=”Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35″ warningLevel=”4″ compilerOptions=”/langversion:6 /nowarn:1659;1699;1701″/> <compiler language=”vb;vbs;visualbasic;vbscript” extension=”.vb” type=”Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35″ warningLevel=”4″ compilerOptions=”/langversion:14[…]

When you try to map an html file in ASP.net and rewrite the URL to remove .html extension such as the example below routes.MapPageRoute(“myhtml”, “myhtml”, “~/Resources/demo/myhtml.html”); It throws an error as following There is no build provider registered for the extension ‘.html’. You can register one in the <compilation><buildProviders> section in machine.config or web.config The following configuration changes in web.config fixes it. <compilation debug=”true” targetFramework=”4.5″ > <buildProviders > <add extension=”.htm” type=”System.Web.Compilation.PageBuildProvider” /> <add extension=”.html” type=”System.Web.Compilation.PageBuildProvider”/> </buildProviders> </compilation>