String maps 编辑

You can use string maps to perform pattern matching in all Citrix ADC features that use the default policy syntax. A string map is a Citrix ADC entity that consists of key-value pairs. The keys and values are strings in either ASCII or UTF-8 format. String comparison uses two new functions, MAP_STRING(<string_map_name>) and IS_STRINGMAP_KEY(<string_map_name>).

A policy configuration that uses string maps performs better than one that does string matching through policy expressions, and you need fewer policies to perform string matching with a large number of key-value pairs. String maps are also intuitive, simple to configure, and result in a smaller configuration.

How String Maps Work

String maps are similar in structure to pattern sets (a pattern set defines a mapping of index values to strings; a string map defines a mapping of strings to strings) and the configuration commands for string maps (commands such as add, bind, unbind, remove, and show) are syntactically similar to configuration commands for pattern sets. Also, as with index values in a pattern set, each key in a string map must be unique across the map. The following table illustrates a string map called url_string_map, which contains URLs as keys and values.

Table 1. String Map “url_string_map”

The following table describes the two functions that have been introduced to enable string matching with keys in a string map. String matching is always performed with the keys. Additionally, the following functions perform a comparison between the keys in the string map and the complete string that is returned by the expression prefix. The examples in the descriptions refer to the preceding example.

For completed information about the two functions introduced for enabling string matching with keys in a string map, see String Map Function table pdf.

Configuring a String Map

You first create a string map and then bind key-value pairs to it. You can create a string map from the command line interface (CLI) or the configuration utility.

To configure a string map by using the command line interface

At the command prompt, do the following:

1. Create a string map.

add policy stringmap <name> -comment <string>

1. Bind a key-value pair to the string map.

bind policy stringmap <name> <key> <value> [-comment <string>]

Example:

bind policy stringmap url_string_map1 "/url_1.html" "http://www.redirect_url_1.com/url_1.html"
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