Variables
The Web Server includes a set of variables predefined by the server, as well as the capability for you to define custom variables. This section includes the following:
Predefined Variables
Predefined variables are implicitly defined by the server. The following table lists the predefined variables and their descriptions:
Table A-1 Predefined Variables
| Variable | Description |
|---|---|
| $n | Regular expression backreference (value of the _n_th capturing subpattern, n = 1...9), for example, $1. Regular expression backreferences are only available within the body of If and ElseIf containers, and only if the container expressions includes one or more regular expressions. For more information on If and ElseIf, see If, ElseIf, and Else. |
| $& | Value that matched a regular expression. Regular expression backreferences are only available within the body of If and ElseIf containers, and only if the container expressions includes one or more regular expressions. For more information on If and ElseIf, see If, ElseIf, and Else. |
| $auth_group | Authenticated user's group (alias for $vars{'auth-group'}). |
| $auth_type | Authentication method (alias for $vars{'auth-type'}). |
| $auth_user | Authenticated user name (alias for $vars{'auth-user'}). |
| $browser | Web browser version (alias for $headers{'user-agent'} if the client sent a User-Agent header or an empty string). |
| $chunked | Boolean variable that indicates whether request body was sent using chunked encoding. |
| $code | Response status code. |
| $cookie{'name'} | Value of the cookie name from request. |
| $dns | Alias for $client{'dns'}. |
| $env{'name'} | Value of the environment variable name (includes CGI/SHTML environment variables). |
| $headers{'name'} | Value of name from rq->headers, that is, value of the request header name where name is a lowercase string. |
| $id | Virtual server ID as specified by the name subelement of the virtual-server element in server.xml. For more information, see virtual-server. |
| $internal | Boolean that indicates whether request was internally generated. |
| $ip | Alias for $client{'ip'}. |
| $keep_alive | Boolean that indicates whether the connection will be kept open. |
| $keysize | Alias for $client{'keysize'}. |
| $method | Request method (alias for $reqpb{'method'}). |
| $path | Requested path (either URI, partial path, or file system path depending on stage).The predefined variable path is the value of path from rq->vars. If path isn't set in rq->vars (for example, if NameTrans hasn't completed), path gets the value of ppath from rq->vars. |
| $path_info | Alias for $vars{'path-info'}. |
| $ppath | Alias for $vars{'ppath'}. |
| $protocol | Request protocol (alias for $reqpb{'protocol'}). |
| $query | Request query string (alias for $reqpb{'query'}). |
| $reason | Response reason phrase. |
| $referer | Alias for $headers{'referer'}. |
| $reqpb{'name'} | Value of name from rq->reqpb. |
| $restarted | Boolean that indicates whether request has been restarted. |
| $secret_keysize | Alias for $client{'secret-keysize'}. |
| $server_url | Prefix for self-referencing URLs. |
| $time | Time the request was received as the number of seconds since 00:00:00 UTC, January 1, 2006. |
| $time_day | Day of the month when the request was received. Value can be from 01 to 31. |
| $time_hour | Hours since midnight when the request was received. Value can be from 00 to 23. |
| $time_min | Minutes after the hour when the request was received. Value can be from 00 to 59. |
| $time_mon | Month of the year when the request was received. Value can be from 01 to 12. |
| $time_sec | Seconds after the minute when the request was received. Value can be from 00 to 61. |
| $time_wday | Day of the week when the request was received. Value can be from 0 to 6, where 0 corresponds to Sunday. |
| $time_year | Four-digit year when the request was received. |
| $type | Alias for $srvhdrs{'content-type'}. |
| $uri | URI of the requested resource (alias for $reqpb{'uri'}). |
| $url | URL of the requested resource. |
| $urlhost | Host name to which the client connected. |
| $vars{'$headers{'name'} | Value of name from rq->vars. |
| $security | Boolean that indicates whether a secure transport was used. |
| $senthdrs | Boolean that indicates whether response headers have been sent. |
| $srvhdrs{'$headers{'name'} | Value of name from rq->srvhdrs, that is, value of response header name where name is a lowercase string. |
Custom Variables
You can define custom variables in the server.xml file using the variables element. These variables can then be used in function parameters in obj.conf functions. You can also define variables at request time using the set-variables function in obj.conf.
For more information, see variable and set-variable.
 | Note - Because predefined variables take precedence over custom variables, it is a best practice to use uppercase names for custom variables. Using uppercase avoids conflicts with the lowercase predefined variables, should the list of predefined variables be extended in the future. |
Resolving Variables
The server uses the following order when attempting to resolve a $variable:
- Predefined variables
- Variables defined at request time using set-variable in obj.conf
- Variables defined by the virtual-server element's variable subelement in server.xml
- Variables defined by the server element's variable subelement in server.xml
When you define a $variable at request time, it is stored as a name-value pair in the rq->vars pblock. These variables are given a higher precedence than server.xml variables so that server.xml variables can be overridden at request time.
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