IIS URL & Request Related Variables

 Sure! These variables are typically found in web server environments like Apache or IIS and are used by server-side applications (like PHP, Python, ASP.NET, etc.) to understand request data, file paths, and configuration settings.

Below is an explanation of each with examples where applicable.

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✅ URL & Request Related Variables

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1. CACHE_URL

• Description: IIS-specific; relates to cached URLs in output caching.

• Example: /cached-page.html

• Use: Used internally by IIS for cached content lookup.

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2. DOCUMENT_ROOT

• Description: The absolute path to the root directory for the web server (where web content is served from).

• Example:
  C:/inetpub/wwwroot (Windows IIS)
  /var/www/html (Apache/Linux)

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3. HTTP_URL

• Description: Often a custom environment variable; not always standard. Could represent the full HTTP URL.

• Example: http://example.com/index.php?user=123

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4. HTTP_HOST

• Description: Host header sent by the client.

• Example: www.example.com

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5. PATH_INFO

• Description: Extra path information provided after the script name in the URL.

• Example: If URL is /index.php/user/123, and script is index.php, then:
  PATH_INFO = /user/123

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6. PATH_TRANSLATED

• Description: Filesystem path equivalent to PATH_INFO.

• Example:
  C:/inetpub/wwwroot/user/123

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7. QUERY_STRING

• Description: The query string part of the URL after the ?.

• Example:
  For /index.php?id=10&name=John,
  QUERY_STRING = id=10&name=John

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8. REQUEST_FILENAME

• Description: The absolute file path to the script being executed.

• Example:
  /var/www/html/index.php

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9. REQUEST_URI

• Description: The full URI as requested by the client, including path and query string.

• Example:
  /index.php?user=123

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10. SCRIPT_FILENAME

• Description: The absolute path to the script being executed (like index.php).

• Example:
  C:/inetpub/wwwroot/index.php

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11. SCRIPT_NAME

• Description: The relative path to the script from the root of the website.

• Example:
  /index.php

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12. SCRIPT_TRANSLATED

• Description: IIS-specific variable; maps the requested URI to a physical path.

• Example:
  If URL is /foo/bar,
  SCRIPT_TRANSLATED = C:\inetpub\wwwroot\foo\bar

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13. UNENCODED_URL

• Description: IIS variable; shows the original URL before encoding.

• Example:
  /path with space/file.html (not URL-encoded)

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14. URL

• Description: IIS variable; the URL portion of the request.

• Example:
  /index.php

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15. URL_PATH_INFO

• Description: IIS variable; similar to PATH_INFO, often used in ISAPI applications.

• Example:
  /extra/path/data

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✅ IIS or Application Pool Related Variables

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16. APP_POOL_ID

• Description: Name of the IIS Application Pool that is processing the request.

• Example:
  DefaultAppPool

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17. APPL_MD_PATH

• Description: The IIS metabase path for the application.

• Example:
  /LM/W3SVC/1/ROOT

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18. APPL_PHYSICAL_PATH

• Description: Physical file system path to the application root.

• Example:
  C:\inetpub\wwwroot\myapp\

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19. GATEWAY_INTERFACE

• Description: The version of the Common Gateway Interface (CGI) used.

• Example:
  CGI/1.1

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20. SERVER_SOFTWARE

• Description: The name and version of the server software.

• Example:
  Microsoft-IIS/10.0
  or
  Apache/2.4.41 (Unix)

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21. SSI_EXEC_DISABLED

• Description: IIS-specific; indicates that execution of commands via Server Side Includes (SSI) is disabled.

• Example:
  true or false

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✅ Summary Table

Variable	Description	Example
CACHE_URL	Cached URL used by IIS	/page.html
DOCUMENT_ROOT	Web root path	C:/inetpub/wwwroot
HTTP_URL	Full URL (not standard)	http://example.com/path
HTTP_HOST	Domain name from Host header	example.com
PATH_INFO	Extra path after script	/user/123
PATH_TRANSLATED	Filesystem path from PATH_INFO	C:/.../user/123
QUERY_STRING	URL query string	id=5&name=test
REQUEST_FILENAME	Full file path to requested file	/var/www/index.php
REQUEST_URI	Entire URI sent by client	/index.php?x=1
SCRIPT_FILENAME	Full file path of the script	C:/.../index.php
SCRIPT_NAME	Relative path to the script	/index.php
SCRIPT_TRANSLATED	Mapped physical path of script (IIS)	C:/.../foo/bar
UNENCODED_URL	Original URL before encoding (IIS)	/path with space/
URL	URL part of the request (IIS)	/index.php
URL_PATH_INFO	Extra path info (IIS)	/info/here
APP_POOL_ID	Name of the app pool (IIS)	DefaultAppPool
APPL_MD_PATH	IIS metabase path	/LM/W3SVC/1/ROOT
APPL_PHYSICAL_PATH	Physical path to application	C:/inetpub/...
GATEWAY_INTERFACE	CGI version	CGI/1.1
SERVER_SOFTWARE	Web server name/version	IIS/10.0
SSI_EXEC_DISABLED	Whether SSI execution is disabled (IIS)	true