The {{Value}} Tag

This tag looks up a value on the server and the tag is replaced with that value.

Value (variable|”variable” [, source] [,operations]…)

By default, variable is a server variable or a special variable (described below). However, options can direct that the value be obtained from the environment, the server configuration, a submitted form, a cookie, or a query parameter.

On BIS/IIS, if variable is enclosed in quotes, the variable name is treated as a literal string and is not resolved further unless one of the source options below is specified.

On BIS/Apache, if variable begins with a quote, it is treated as a literal and no source option is permitted.

Either single or double quotes may be used as delimiters, and a delimiting quote may be embedded in the string by specifying the quote twice: "abc'""def" becomes abc"def.

The source option determines from where the variable value is obtained. If specified, the source must be the second parameter.

`SERVER`	Specifies that `variable` is a server variable. This is the default if none of the other sources below are specified and if the string is not quoted. Under BIS/Apache, `ENV` and `SERVER` are identical.
`CONFIG`	Specifies that `variable` is a special server configuration value. A list of `CONFIG` variables appears at the end of this section.
`COOKIE`	Specifies that `variable` is a cookie.
`ENV`	Specifies that `variable` is an environment variable instead of a server variable. Note that, on BIS/Apache, `ENV` and `SERVER` are identical. See Setting Environment Variables for information about setting and modifying environment variables on Windows.
`FORM`	Specifies that `variable` is a `<form>` variable.
`QUERYPARAM` `QP`	Specifies that `variable` is a URL query parameter. `QP` is accepted as an alias for `QUERYPARAM` .

These operations modify the retrieved value and are applied from left to right and may be applied multiple times.

`DEFAULT=value`	Specifies a default value for `variable` if the `variable` is empty. This option has no effect unless the `variable` is empty at the point the `DEFAULT` operation is performed. If the `variable` is empty when the end of the entire operations list is reached, the `Value` tag is simply removed from the output stream. If `DEFAULT` is encountered and the `variable` is empty, the tag is replaced by `value`. If there are additional operations to the right of the `DEFAULT` operation (that is, `GETDIR` , `TOUPPER`, `URLENCODE`), these are performed on the new defaulted `value`.
`GETDIR`	Same as `GETPATH` (see below), except only the directory portion of the pathname is extracted. This is the part of the pathname that follows the scheme and hostname up to the last slash in the pathname. Note that if `variable` is a pathname that contains a drive letter, the drive letter is also returned. The extracted pathname never ends in a slash.
`GETQUERYSTRING`	If `variable` is a URL, returns the query string. If not present or if `variable` is a pathname, an empty string is returned.
`GETHOST`	If `variable` is a URL, extracts the hostname. If `variable` is a pathname, or no host name is present, an empty string is returned.
`GETNAME`	Same as `GETPATH` , except only the filename portion of the pathname is extracted. This is the part of the pathname that follows the last slash but excludes the `#fragment` , `?querystring`, and `;parameters`.
`GETPATH`	If `variable` is a URL, extracts the path portion of the URL. This is the portion of the URL that excludes the scheme, the hostname, and the query string. If variable is a pathname, it is unchanged.
`GETSCHEME`	If `variable` is a URL, extracts the scheme. This will normally be `http` or `https` without the terminating colon or slashes. If `variable` is a pathname or a URL without a scheme, an empty string is returned.
`SUBSTITUTE= pattern/replacement/` `SUB=/pattern/replacement/`	Allows you to substitute all occurrences of `pattern` in the value with a replacement pattern. The operation is performed on the current value after all transforms to the left have been performed. Processing continues with the modified value. `SUB` is accepted in place of `SUBSTITUTE` for brevity. Both `pattern` and `replacement` are regular expressions. (For more information, see Regular Expression Syntax).
`TOUPPER`	Converts the value to all upper-case characters. Equivalent to `SUBSTITUTE="/.*/\U&/"`.
`TOLOWER`	Converts the value to all lower-case characters. Equivalent to `SUBSTITUTE="/.*/\L&/"`.
`URLDECODE`	Decodes a string that has been URL-encoded. This is primarily useful when retrieving a server variable.
`URLENCODE`	Encodes a string for reliable HTTP transmission from the web server to a client as a URL. For example, `This is a <Test String>.` will be encoded as: `This%20is%20a%20%3cTest%20String%3e.`
`HTMLDECODE`	Decodes a string that has been HTML-encoded. This is primarily useful when retrieving a server variable.
`HTMLENCODE`	Encodes a string for reliable HTTP transmission from the web server to a client as HTML. For example, `This is a <Test String>.` will be encoded as: `This is a <Test String>`.
`MAKEABS`	Assumes that the string is a relative URL, and makes the URL absolute, using the location of the stencil that was requested by the client as the base URL (see `REQUEST_URL` in Configuration Variables for details). If the string is not a URL, it is not altered. If the input string is an absolute URL, it is cleaned up (that is, redundancies such as dir/../ are removed) but is otherwise unchanged. See RFC 3986 for details about how relative URLs are resolved by this operation.

Processing stops when the following option is encountered and the tag always renders as an empty string.

MATCH=regexp

Applies the regular expression against the current value and returns true if it matches and false if it does not match but does not return any text for rendering. This allows Value to be used in If tags. See Regular Expression Syntax.

For example, the tag:

{{ VALUE (HTTP_URL, GETDIR, TOLOWER, URLENCODE) }}

is replaced by the directory that contains the page that is currently being served. The name of the directory is converted to lowercase and the directory name is URL-encoded (for example, recommended if the value will be substituted into an HREF attribute). HTTP_URL is a server variable, but it is not necessary to specify the SERVER source parameter because this is the default.

On Windows XP, the tag:

{{ VALUE (PROCESSOR_IDENTIFIER, ENV, DEFAULT=”Unknown”, HTMLENCODE) }}

is replaced by the contents of the PROCESSOR_IDENTIFIER environment variable. If this variable is not defined, the text Unknown (without quotes) is output instead. The output is HTML-encoded so any < or > characters in the environment variable are properly converted.