The document discusses configuration files in ASP.NET applications. Web.config is the main configuration file for a website and is used to manage settings independently from code. It and other configuration files like Machine.config allow compartmentalizing applications for improved reliability. Global.asax handles application and session events and is where event handlers are defined.

1. By-Teach4u.in

2. Content
1. Web.config
2. Why Applications?
3. IIS
1. Role in handing a request
4. .NET
1. Applications
2. Application Object
3. Global.asax
5. Configuration files
1. Machine.config
2. Web.Config

3. What is Web.Config File?
Configuration file is used to manage various settings
that define a website. The settings are stored in XML
files that are separate from your application code. In
this way you can configure settings independently
from your code. Generally a website contains aingle
Web.config file stored inside the application root
directory. However there can be many configuration
files that manage settings at various levels within an
application.

4. Why Applications?
Dark ages (pre-2003)
Server crashes not unusual
 Single failure bring down whole system
Worse yet:
 Memory leaks
 Cause IIS hang
 Stop serving pages
 Required manual intervention
(reboot)

5. Why Applications
Today (Windows Server 2003 & later)
Applications still crash
 Applications are compartmentalized
 OS handles gracefully
System rarely affected
OS monitors application health
 Recycles unhealthy processes
Result: system stable & reliable

6. IIS Overview

7. IIS Applications
Folders may be configured as “Applications”
IIS configuration interface
Each application is assigned to an Application Pool
 Each application pool has a unique Windows process
Specify error handling, timeouts, etc. for each application
Benefit:
Compartmentalize applications
Reduces dependencies
 Improves reliability
Allows application specific settings
 Error handling, log files, filters, headers, timeouts…
 100’s of settings

8. Applications Settings
Configuration settings:
Web.config
 Application level settings
 Located in root folder
Machine.config
 Settings common to all applications
Application event handlers
Global.asax file
 Located in root folder

9. ASP.NET Configuration
.config files
Hierarchical configuration
Similar to CSS
 Inheritance
 Child has precedence over parent
Machine.config
Rarely need to modify

10. Web.Config
XML file
Case sensitive
Camel casing
Configure:
Application settings
Error handling
Timeouts
Sessions…etc. etc.
Authentication
documentation
Security
.config files not served

11. Global.asax
Handles application & session events
15+ events
Application_start
Application_error
Session_start
Located in root folder of application
Triggered each page request
Optional

12. Global.asax
Example:
Create new application on server
web.config: source
global.asax: source
TestPage.aspx: source, output

13. Summary
Configuration Objectives:
 Flexibility
 Security
 Reliability
 Convenience
IIS
 Handles requests
Application
 Application object
 Events: global.asax
Configuration
 Machine.config
 Web.config