Citrix Systems 9.2 Expression Prefixes for VPNs and Clientless VPNs

76 Citrix NetScaler Policy Configuration and Reference Guide
Expression Prefixes for VPNs and Clientless
VPNs
The advanced expression engine provides prefixes that are specific to parsing
VPN or Clientless VPN data. This data includes the following:
• Host names, domains, and URLs in VPN traffic.
• Protocols in the VPN traffic.
HTTP.REQ.URL.PATH.
IGNORE_EMPTY_ELEMENTS Ignores the empty elements in the list. For example, if
the element delimiter in the list is a comma, the
following list has an empty element following a=10:
a=10,b=11, ,c=89
The element following b=11 is not considered an empty
element.
As another example, consider the following header:
Cust_Header : 123,,24, ,15
The following expression returns a value of 4:
http.req.header("Cust_Header").typecast_
list_t(',').ignore_empty_elements.count
The following expression returns a value of 5:
http.req.header("Cust_Header").typecast_
list_t(','). count
HTTP.REQ.URL.QUERY.
IGNORE_EMPTY_ELEMENTS This method ignores the empty elements in a name-
value list. For example, if the list delimiter is a
semicolon, the following list has an empty element
following a=10:
a=10;;b=11; ;c=89
The element following b=11 is not considered an empty
element.
For example, consider the following header:
Cust_Header : a=1;;b=2; ;c=3
The following expression returns a value of 4:
http.req.header("Cust_Header").typecast_
nvlist_t('=',';').ignore_empty_elements.
count
The following expression returns a value of 5:
http.req.header("Cust_Header").typecast_
nvlist_t('=',';'). count
HTTP Expression Prefixes that Return Text
Prefix Description