## org.apache.catalina.servlets
Class CGIServlet.CGIEnvironment

    java.lang.Object
      org.apache.catalina.servlets.CGIServlet.CGIEnvironment

Enclosing class:
  CGIServlet

    protected class CGIServlet.CGIEnvironment

extends java.lang.Object

Encapsulates the CGI environment and rules to derive that environment from the servlet container and request information.

Since:
  Tomcat 4.0
Version:
  $Revision: 677714 $, $Date: 2008-07-17 22:37:29 +0200 (Thu, 17 Jul 2008) $

Constructor Summary
`protected` `CGIServlet.CGIEnvironment(javax.servlet.http.HttpServletRequest req, javax.servlet.ServletContext context)` Creates a CGIEnvironment and derives the necessary environment, query parameters, working directory, cgi command, etc.

Method Summary
`protected java.lang.String` `blanksToString(java.lang.String couldBeBlank, java.lang.String subForBlanks)` Converts blank strings to another string
`protected void` `expandCGIScript()` Extracts requested resource from web app archive to context work directory to enable CGI script to be executed.
`protected java.lang.String[]` `findCGI(java.lang.String pathInfo, java.lang.String webAppRootDir, java.lang.String contextPath, java.lang.String servletPath, java.lang.String cgiPathPrefix)` Resolves core information about the cgi script.
`protected java.lang.String` `getCommand()` Gets derived command string
`protected java.util.Hashtable` `getEnvironment()` Gets derived CGI environment
`protected java.util.ArrayList` `getParameters()` Gets derived CGI query parameters
`protected java.io.File` `getWorkingDirectory()` Gets derived CGI working directory
`protected boolean` `isValid()` Gets validity status
`protected java.lang.String` `nullsToBlanks(java.lang.String s)` Converts null strings to blank strings ("")
`protected java.lang.String` `nullsToString(java.lang.String couldBeNull, java.lang.String subForNulls)` Converts null strings to another string
`protected boolean` `setCGIEnvironment(javax.servlet.http.HttpServletRequest req)` Constructs the CGI environment to be supplied to the invoked CGI script; relies heavliy on Servlet API methods and findCGI
`protected void` `setupFromContext(javax.servlet.ServletContext context)` Uses the ServletContext to set some CGI variables
`protected void` `setupFromRequest(javax.servlet.http.HttpServletRequest req)` Uses the HttpServletRequest to set most CGI variables
`java.lang.String` `toString()` Print important CGI environment information in a easy-to-read HTML table

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Constructor Detail

### CGIServlet.CGIEnvironment

    protected CGIServlet.CGIEnvironment(javax.servlet.http.HttpServletRequest req,
                                        javax.servlet.ServletContext context)
                                 throws java.io.IOException

  Creates a CGIEnvironment and derives the necessary environment, query parameters, working directory, cgi command, etc.

  Parameters:
    `req` - HttpServletRequest for information provided by the Servlet API
    `context` - ServletContext for information provided by the Servlet API
  Throws:
    `java.io.IOException`

Method Detail

### setupFromContext

    protected void setupFromContext(javax.servlet.ServletContext context)

  Uses the ServletContext to set some CGI variables

  Parameters:
    `context` - ServletContext for information provided by the Servlet API

### setupFromRequest

    protected void setupFromRequest(javax.servlet.http.HttpServletRequest req)
                             throws java.io.UnsupportedEncodingException

  Uses the HttpServletRequest to set most CGI variables

  Parameters:
    `req` - HttpServletRequest for information provided by the Servlet API
  Throws:
    `java.io.UnsupportedEncodingException`

### findCGI

    protected java.lang.String[] findCGI(java.lang.String pathInfo,
                                         java.lang.String webAppRootDir,
                                         java.lang.String contextPath,
                                         java.lang.String servletPath,
                                         java.lang.String cgiPathPrefix)

  Resolves core information about the cgi script.

  Example URI:

       /servlet/cgigateway/dir1/realCGIscript/pathinfo1

  - path = $CATALINA_HOME/mywebapp/dir1/realCGIscript
  - scriptName = /servlet/cgigateway/dir1/realCGIscript
  - cgiName = /dir1/realCGIscript
  - name = realCGIscript

  CGI search algorithm: search the real path below <my-webapp-root> and find the first non-directory in the getPathTranslated("/"), reading/searching from left-to-right.

  The CGI search path will start at webAppRootDir + File.separator + cgiPathPrefix (or webAppRootDir alone if cgiPathPrefix is null).

  cgiPathPrefix is defined by setting this servlet's cgiPathPrefix init parameter

  Parameters:
    `pathInfo` - String from HttpServletRequest.getPathInfo()
    `webAppRootDir` - String from context.getRealPath("/")
    `contextPath` - String as from HttpServletRequest.getContextPath()
    `servletPath` - String as from HttpServletRequest.getServletPath()
    `cgiPathPrefix` - subdirectory of webAppRootDir below which the web app's CGIs may be stored; can be null. The CGI search path will start at webAppRootDir + File.separator + cgiPathPrefix (or webAppRootDir alone if cgiPathPrefix is null). cgiPathPrefix is defined by setting the servlet's cgiPathPrefix init parameter.
  Returns:
    - `path` - full file-system path to valid cgi script, or null if no cgi was found
    - `scriptName` - CGI variable SCRIPT_NAME; the full URL path to valid cgi script or null if no cgi was found
    - `cgiName` - servlet pathInfo fragment corresponding to the cgi script itself, or null if not found
    - `name` - simple name (no directories) of the cgi script, or null if no cgi was found
  Since:
    Tomcat 4.0

### setCGIEnvironment

    protected boolean setCGIEnvironment(javax.servlet.http.HttpServletRequest req)
                                 throws java.io.IOException

  Constructs the CGI environment to be supplied to the invoked CGI script; relies heavliy on Servlet API methods and findCGI

  Parameters:
    `req` - request associated with the CGI invokation
  Returns:
    true if environment was set OK, false if there was a problem and no environment was set
  Throws:
    `java.io.IOException`

### expandCGIScript

    protected void expandCGIScript()

  Extracts requested resource from web app archive to context work directory to enable CGI script to be executed.

### toString

    public java.lang.String toString()

  Print important CGI environment information in a easy-to-read HTML table

  Overrides:
    `toString` in class `java.lang.Object`
  Returns:
    HTML string containing CGI environment info

### getCommand

    protected java.lang.String getCommand()

  Gets derived command string

  Returns:
    command string

### getWorkingDirectory

    protected java.io.File getWorkingDirectory()

  Gets derived CGI working directory

  Returns:
    working directory

### getEnvironment

    protected java.util.Hashtable getEnvironment()

  Gets derived CGI environment

  Returns:
    CGI environment

### getParameters

    protected java.util.ArrayList getParameters()

  Gets derived CGI query parameters

  Returns:
    CGI query parameters

### isValid

    protected boolean isValid()

  Gets validity status

  Returns:
    true if this environment is valid, false otherwise

### nullsToBlanks

    protected java.lang.String nullsToBlanks(java.lang.String s)

  Converts null strings to blank strings ("")

  Parameters:
    `s` - string to be converted if necessary
  Returns:
    a non-null string, either the original or the empty string ("") if the original was `null`

### nullsToString

    protected java.lang.String nullsToString(java.lang.String couldBeNull,
                                             java.lang.String subForNulls)

  Converts null strings to another string

  Parameters:
    `couldBeNull` - string to be converted if necessary
    `subForNulls` - string to return instead of a null string
  Returns:
    a non-null string, either the original or the substitute string if the original was `null`

### blanksToString

    protected java.lang.String blanksToString(java.lang.String couldBeBlank,
                                              java.lang.String subForBlanks)

  Converts blank strings to another string

  Parameters:
    `couldBeBlank` - string to be converted if necessary
    `subForBlanks` - string to return instead of a blank string
  Returns:
    a non-null string, either the original or the substitute string if the original was `null` or empty ("")

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