Alexey Polovinkin Post graduate student, CMC department

 Anatomy of ASP.NET application  The global.asax application file  ASP.NET configuration .NET Components  Extending HTTP pipeline

 All the web pages in a single web application: ◦ share the same in-memory resources (global application data, per-user session data, cached data) ◦ share the same core configuration settings  Virtual directory is the basic grouping structure that delimits ASP.NET applications

 web pages (.aspx files)  web services (.asmx files)  WCF services (.svc files)  core-behind files  a configuration file (web.config)  global.asax  other components

 ASP.NET uses lazy initialization technique for creating application domains.  Application can restart himself in new application domain: ◦ in response to error conditions; ◦ depending on settings in the computer-wide machine.config file, when certain thresholds are reached (length of application domain runtime, the number of queued requests, the amount of memory used, etc.) (see chapter 18) ◦ when application is changed (modifying web.config, replacing existing web page or DLL assembly)  ASP.NET starts new application domain to handle all future requests and keeps the existing application domain alive long enough to finish handling requests.

 There is an opportunity to update ASP.NET application without needing to restart web server and without worrying about existing clients.  ASP.NET uses shadow copy technique  ASP.NET ability to detect changing original files relies on ability of Windows system to track directories and files and send immediate change notification.  You can use assemblies from GAC and put your own assemblies into GAC.

DirectoryDescription BinAll the precompiled.NET assemblies (usually DLLs) that the ASP.NET web application uses App_CodeSource code files that are dynamically compiled for application App_Global Resources Global resources that are accessible to every page in the web application App_Local Resources Resources that are accessible for dedicated pages only App_Web References References to web services that web application uses (WSDL files and discovery documents) App_DataData storage, including SQL Server 2005 Express database files and XML files App_BrowsersBrowser definitions stored in XML files (see Chapter 27) App_ThemesThe themes used by the web application (see Chapter 16)

 contains event handlers to react global events  defines the methods for application class (derives from HttpApplication)  doesn’t contain any HTML or ASP.NET tags

 Application_Start()  Session_Start()  Application_Error()  Session_End()  Application_End()  Application_Disposed()

 %WINDIR%\Microsoft.NET\Framework\v \Config  defines supported configuration file sections;  configures ASP.NET worker process;  registers providers for advanced features (profile, membership, role-based security)

 configure how ASP.NET worker process recycles application;  configure Windows account it executes under;  Ignored by IIS >= 6.0

 Allow to set the server-specific key used for encrypted data and creating digital signatures ◦ machine specific, application specific keys ◦ single key for all applications on the computer ◦ definition of the keys explicitly ◦ definition of the application-specific keys explicitly in the web.config file

 validationKey value can be from 40 to 128 characters long  decriptionKey value can be either 16(DES) or 48(3DES) characters long  safety rules: ◦ use maximum length key available ◦ use.NET Framework cryptography classes (System.Security.Cryptography namespace)

 - entire content of ASP.NET configuration ◦ - ASP.NET configuration settings ◦ - store custom application settings ◦ - store connection strings to databases.

 Allows to specify more than one group of settings in the same configuration file

 section can be used to lock specific settings so they can’t be overridden

you can use as few or as many configuration sections as you want web.config file is case-sensetive

 allows to configure the behavior of ASP.NET application to response to various HTTP errors  Supported modes: ◦ On – custom errors are enabled; ◦ Off – custom errors are disabled; ◦ RemoteOnly – custom errors are shown only to remote clients but full detailed errors are displyed to local clients  Custom error settings defined in configuration file come into effect only if ASP.NET is handling the request

 allows to define database connection strings that will be used in application

 allows adding custom settings to the application 

 System.Configuration namespace  ConfigurationSettings class  AppSettings property

 System.Web.Configuration namespace  WebConfigurationManager class

 OpenWebConfiguration() method reflects the cumulative configuration for the current application  OpenWebConfiguration() method returns Configuration object that contains all configuration information

 element can be used to store custom information that application uses, but ◦ it doesn’t provide a way to store structured information ◦ it’s limited to single strings  to extend a configuration file: ◦ determine information to store in configuration file and its structure ◦ for each element create C# class that encapsulates information ◦ register new element in configuration file (use element)  Example

 ASP.NET supports two encryption options: ◦ RSA ◦ DPAPI (data protection API)  Programmatic encryption ◦ ProtectSection() – encrypt data in section; ◦ UnprotectSection() – switch off encryption;  Command-line encryption (with regiis_asp) ◦ -pe specifies configuration section to encrypt ◦ -app specifies web application’s virtual path ◦ -prov specifies provider name

 Two ways to create a component: ◦ Create a new.cs file in the App_Code subdirectory ◦ Create a new class library project in Visual Studio

 HTTP handlers are defined in section of configuration file (nested in the element)  - register new handler  - unregister existing handler

 participate in processing of a request by handling application events  a request can flow trough multiple HTTP modules but it always ends with single HTTP handler

 HTTP modules are defined in section of configuration file (nested in the element)  - register new module  - unregister existing module

 To create a custom HTTP handler you need to make a class that implements IHttpHandler interface

 verb = “*” (use for both HTTP POST and HTTP get requests)  path – indicates the file extension that will invoke HTTP handler  type – identifies HTTP handler class

 To create a custom HTTP handler you need to make a class that implements IHttpHandler interface