Configuring, Deploying, Tracing and Error Handling

Configuring, Deploying, Tracing and Error Handling IT533 Lectures

IIS • Internet Information Server • Microsoft’s web server • http://www.iis.net/ • Foundation for ASP.NET • Runs in inetinfo.exe process • Also FTP, NNTP, SMTP • Shared resources • Default location c:\inetpub\wwwroot • Internet Services Manager • A Microsoft Management Console (MMC) snap-in

IISVirtual Directories • Provides a level of indirection from URL to actual file locations on the server • For example, the file for the url: http://myServer/myApplication/foo.aspcould be mapped to the physical location:d:\myFolder\myAppFolder\foo.asp

Deployment • XCOPY deployment • Components are placed in .\bin folder • No DLL deployment, registration • Unless you’re using COM or other DLLs • No locked DLLs • DLLs are “shadow copied” into a hidden folder • .aspx files are automatically compiled • Not true for codebehind • Update code (.aspx and assemblies) while server is running • No need to stop/bounce the server

Demo • Let’s take a website we’ve implemented and deloy it to our IIS server. • Look at Properties of the application:

Configuration • Goal • Provide extensible configuration for admins & developers to hierarchically apply settings for an application • Solution • Store configuration data in XML text files • Format is human- and machine- readable and writable

Configuration • Settings specified in configuration sections, e.g. • Security, SessionState, Compilation, CustomErrors, ProcessModel, HTTPHandlers, Globalization, AppSettings, WebServices, WebControls, etc. • Configuration information stored in web.config • It is just a file, no DLL registration, no Registry settings, no Metabase settings • <!– web.config can have comments -->

Root Dir web.config Sub Dir1 Sub Dir2 ConfigurationConfiguration Hierarchy • Configuration files can be stored in application folders • Configuration system automatically detects changes • Hierarchical configuration architecture • Applies to the actual directory and all subdirectories

Configurationweb.config Sample • web.config sample <configuration> <configsections> <add names=“httpmodules“ type=“System.Web.Config.HttpModulesConfigHandler“/> <add names=“sessionstate“ type=“...“/> </configsections> <httpmodules>  </httpmodules> <sessionstate>  </sessionstate></configuration>

ConfigurationConfiguration Hierarchy • Standard machine-wide configuration file • Provides standard set of configuration section handlers • C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\machine.config

ConfigurationUser-defined Settings • In root web.config <appSettings> <add key="customsetting1" value="Some text here"/> </appSettings> • Retrieve settings at run-time • string customSetting = System.Configuration.ConfigurationManager.AppSettings.Get("customsetting1");

Tracing • ASP.NET supports tracing • Easy way to include “debug” statements • No more messy Response.Write() calls! • Debug statements can be left in, but turned off • Great way to collect request details • Server control tree • Server variables, headers, cookies • Form/Query string parameters • Tracing provides a wealth of information about the page • Can be enabled at page- or application- level • http://msdn.microsoft.com/en-us/library/0x5wc973.aspx

TracingMethods and Properties • Methods • Trace.Write: Writes category and text to trace • Trace.Warn: Writes category and text to trace in red • Properties • Trace.IsEnabled: True if tracing is turned on for the application or just that page • Trace.Mode: SortByTime, SortByCategory • Implemented in System.Web.TraceContext class

TracingApplication-Level Tracing • To enable tracing across multiple pages: • Write web.config file in application root • Hit one or more pages in the application • Access tracing URL for the application • <configuration> • <system.web> • <trace enabled="true" pageOutput="false" • requestLimit="40" localOnly="false"/> • </system.web> • </configuration> http://localhost:port/WebsiteName/Trace.axd

TracingPage-Level Tracing • To enable tracing for a single page: • Add trace directive at top of page • <%@ Page Trace=“True” %> • Add trace calls throughout page • Trace.Write(“MyApp”, “Button Clicked”); • Trace.Write(“MyApp”, “Value: ” + value); • Access page from browser

TracingTracing Demo • Let’s add some traces to the AjaxExample website • Show information obtained from tracing

Error Handling • .NET Common Language Runtime provides a unified exception architecture • Runtime errors done using exceptions • VB now supports try/catch/finally • ASP.NET also provides declarative application custom error handling • Automatically redirect users to error page when unhandled exceptions occur • Prevents ugly error messages from being sent to users

Error HandlingCustom Error Pages • Can specify error pages for specific HTTP status codes in web.config • <configuration> • <customerrors mode=“remoteonly” • defaultredirect=“error.htm”> • <error statuscode=“404” • redirect=“adminmessage.htm”/> • <error statuscode=“403” • redirect=“noaccessallowed.htm”/> • </customerrors> • </configuration>

Error HandlingCustom Error Pages • Can configure error pages on IIS Properties

Error HandlingError Event • What do you actually do when an error occurs? • Add global.asax to your website • Use System.Diagnostics.EventLog class to write custom events to log when errors occur • Use System.Web.Mail.SmtpMailclass to send email to administrators

Configuring, Deploying, Tracing and Error Handling