MsBuild CodeTaskFactory Custom Task to Warming Up a Web App

I remember reading about the MSBuild CodeTaskFactory a couple years ago and hadn't run into a situation where I needed it until now. CodeTaskFactory is a great way to extend MSBuild's capabilities without having to go through the hassle of creating a custom MSBuild Task and having to make sure everyone has the dll.

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<UsingTask TaskName="TestWebAppAvailable" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll" >   <ParameterGroup>     <hostname ParameterType="System.String" Required="true" />     <servers ParameterType="System.String[]" Required="true" />     <Result ParameterType="System.String" Output="true" />     <!--<TestSuccess ParameterType="System.Boolean" Output="true" />-->   </ParameterGroup>   <Task>     <!--<Reference Include="System.Xml"/>-->     <Reference Include="System.IO"/>     <Reference Include="System.Net"/>     <Using Namespace="System"/>     <Using Namespace="System.IO"/>     <Using Namespace="System.Net"/>     <Code Type="Fragment" Language="cs">       <![CDATA[ string requestUrl = "http://" + hostname + "/Default.aspx"; Result = "success"; foreach (string server in servers) {     Log.LogMessage("Server: " + server, MessageImportance.Normal);     if (string.IsNullOrEmpty(server))     {         continue;     }     Log.LogMessage("Warming up: " + requestUrl, MessageImportance.Normal);     System.Net.HttpWebResponse res = null;     try     {         System.Net.WebRequest wr = System.Net.WebRequest.Create(requestUrl);         wr.Timeout = 20000;         wr.Proxy = new System.Net.WebProxy("http://" + server, false);         res = (HttpWebResponse)wr.GetResponse();         Log.LogMessage(server + " - " + res.StatusCode, MessageImportance.Normal);     }     catch (System.Net.WebException ex)     {         res = (HttpWebResponse)ex.Response;         Log.LogMessage("EXCEPTION: " + ex.ToString(), MessageImportance.High);         Log.LogMessage("res == null: " + (res == null).ToString(), MessageImportance.High);         Log.LogMessage("Server: " + server, MessageImportance.High);         Log.LogMessage("res.StatusCode: " + (res != null ? res.StatusCode.ToString() : "Res was null"), MessageImportance.High);     }     catch (System.Exception ex) {         throw;     }     Log.LogMessage("res == null: " + (res == null).ToString(), MessageImportance.High);     if (res.StatusCode != System.Net.HttpStatusCode.OK)     {         string message = server + " Web request failed with code: " + res.StatusCode.ToString();         System.Net.WebException exception = new System.Net.WebException(message);         if (res != null)         {             res.Close();         }         Result = server;         Log.LogMessage("EXCEPTION: " + message, MessageImportance.High);         break;     }           if (res != null)     {         res.Close();     } } ]]>     </Code>   </Task> </UsingTask>

Basically this takes in a host header for the hostname and a list of servers. It then iterates over the servers and requests the Default.aspx page. A successful request returns "success". A request that returns a status code that is not 200 returns the server name that failed.

Then using the new custom task is as easy as the following:

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<ItemGroup>   <Servers Include="$(DeploymentWebServer1)"></Servers>   <Servers Include="$(DeploymentWebServer2)"></Servers> </ItemGroup> <TestWebAppAvailable hostname="$(DeploymentHostname)" servers="@(Servers)" ContinueOnError="True">   <Output TaskParameter="Result" PropertyName="TestResult" /> </TestWebAppAvailable> <Error Text="Server $(TestResult) returned a bad response.  Recopy web application files." Condition="'$(TestResult)' != 'success'" />