Citrix Application Delivery Management

Built-in functions

Expressions in StyleBooks can make use of built-in functions.

For example, you can use the built-in function, str() to transform a number to a string.

str($parameters.order)

Or, you can use the built-in function, int() to transform a string into an integer.

int($parameters.priority)

The following is the list of built-in functions supported in StyleBook expressions with examples of how they can be used:

str()

The str() function transforms the input argument to a string value.

Allowed argument types:

  • string
  • number
  • TCP-port
  • boolean
  • IP address

Examples:

  • “set-“ + str(10) returns “set-10”
  • str(10) returns “10”
  • str(1.1.1.1) returns “1.1.1.1”
  • str(T rue) returns “T rue”
  • str(mas) returns “mas”

int()

The int() function takes a string, number, IP address, or tcpport as an argument and returns an integer.

Examples:

  • The int("10") function returns 10.
  • The int(10) function returns 10.
  • The int(ip('0.0.4.1')) function returns 1025.

bool()

The bool() function takes any type as an argument. If the argument value is false, empty, or non-existent, this function returns false.

Otherwise, it returns true.

Examples:

  • bool(true) returns “true”
  • bool(false) returns “false”
  • bool($parameters.a) returns false if the
  • $parameters.a is false, empty, or not present.

len()

The len() function takes a string or a list as an argument, and returns the number of characters in a string or the number of items in a list.

Example 1:

If you define a substitution as follows:

items: [“123”, “abc”, “xyz”]

len($substitutions.items) returns 3

Example 2:

len(“netscaler mas”) returns 13

Example 3:

len($parameters.vips) returns 3 if $parameters.vip is assigned a value [‘1.1.1.1’, ‘1.1.1.2’, ‘1.1.1.3’]

min()

The min() function takes either a list or a series of numbers or tcp-ports as arguments, and returns the smallest item.

Examples with a series of numbers/tcp-ports:

  • min(80, 100, 1000) returns 80
  • min(-20, 100, 400) returns -20
  • min(-80, -20, -10) returns -80
  • min(0, 100, -400) returns -400

Examples with a list of numbers/tcp-ports:

  • Support $parameters.ports is a list of tcp-ports and has value: [80, 81, 8080].

    min($parameters.ports) returns 80.

max()

The max() function takes either a list or a series of numbers or tcp-ports as arguments, and returns the largest item.

Examples with a series of numbers/tcp-ports:

  • max(80, 100, 1000) returns 1000
  • max(-20, 100, 400) returns 400
  • max(-80, -20, -10) returns -10
  • max(0, 100, -400) returns 100

Examples with a list of numbers/tcp-ports:

  • Support $parameters.ports is list of tcp-ports and has value: [80, 81, 8080].

    max($parameters.ports) returns 8080.

bin()

The bin() function takes a number as an argument, and returns a string that represents the number in binary format.

Examples of expressions:

bin(100) returns “0b1100100”

oct()

The oct() function takes a number as an argument, and returns a string that represents the number in octal format.

Examples of expressions:

oct(100) returns “0144”

hex()

The hex() function takes a number as an argument, and returns a lowercase string that represents the number in hexadecimal format.

Examples of expressions:

hex(100) returns “0x64”

lower()

The lower() function takes a string as an argument and returns the same string in lowercase.

Example:

lower(“MAS”) returns “mas”

upper()

The upper() function takes a string as an argument and returns the same string in uppercase.

Example:

upper(“netscaler_mas”) returns “NET SCALER_MAS”

sum()

The sum() function takes a list of numbers or tcpports as arguments and returns the sum of the numbers in the list.

Example 1:

If you define a substitution as follows: substitutions:

  • list-of-numbers:

    • 11
    • 22
    • 55

    sum($substitutions.list-of-numbers) returns 88

Example 2:

If $parameters.ports is [80, 81, 82], sum($parameters.ports) returns 243

pow()

The pow() function takes two numbers as arguments and returns a number that represents the first argument raised to the power of the second one.

Example:

pow(3,2) returns 9

ip()

The ip function takes a string or an ipaddress as argument returns the IP address based on the input value.

Examples:

  • ip(“2.1.1.1”) returns “2.1.1.1”
  • ip(3.1.1.1) returns “3.1.1.1”

ip()

The ip() function takes an integer, string, or an IP address as an argument and returns the IP address based on the input value.

Examples:

  • Specify an IP address in the ip function:

    The ip(3.1.1.1) function returns 3.1.1.1.

  • Specify a string in the ip function:

    The ip('2.1.1.1') function returns 2.1.1.1

  • Specify an integer in the ip function:

    • The ip(12) function returns 0.0.0.12.

    • When you specify an integer as string in the ip function, it returns an equivalent IP address of the input.

      The ip('1025') function returns 0.0.4.1.

    This function also supports the integer addition and subtraction operations and returns a resultant IP address.

    • Addition: The ip(1025) + ip(12) function returns 0.0.4.13.

    • Subtraction: The ip('1025') - ip(12) function returns 0.0.3.245.

    • Combine addition and subtraction: The ip('1.1.1.1') + ip('1.1.1.1') – ip(2) returns 2.2.2.0.

base64.encode()

The base64.encode() function takes a string argument and returns the base64 encoded string.

Example:

base64.encode(“abcd”) returns “YWJjZA==”

base64.decode()

The base64.decode function takes base64 encoded string as an argument and returns the decoded string.

Example:

base64.decode(“YWJjZA==”) returns “abcd”

exists()

The exists function takes an argument of any type and returns a Boolean. The return value is True if the input has any value. The return value is False If the input argument does not have a value (that is, no value).

Consider that the $parameters.monitor is an optional parameter. If you provide a value to this parameter when creating a configpack, exists($parameters.monitor) returns True.

Otherwise, it returns False.

filter()

The filter() function takes two arguments.

Argument 1: a substitution function that takes one argument and returns a Boolean value.

Argument 2: a list.

The function returns a subset of the original list where each element evaluates to “True” when passed to the substitution function in the first argument.

Example:

Suppose we have defined a substitution function as follows.

substitutions:

x(a): $a != 81

This function returns True if the input value is not equal to 81. Otherwise, it returns False.

Suppose,

$parameters.ports is [81, 80, 81, 89]

filter($substitutions.x, $parameters.ports) returns [80, 89] by removing all occurrences of 81 from the list.

if-then-else()

The function if-then-else() takes three arguments.

Argument 1: Boolean expression

Argument 2: Any expression

Argument 3: Any expression (optional)

If the expression in argument 1 evaluates to True, the function returns the value of the expression provided as argument 2.

Otherwise, if argument 3 is provided, the function returns the value of the expression in argument 3.

If argument 3 is not provided, the function returns no value.

Example 1:

if-then-else($parameters.servicetype == HTTP, 80, 443) returns “80” if $parameters.servicetype has value “HTTP.” Otherwise, the function returns “443”.

Example 2:

if-then-else($parameters.servicetype == HTTP, $parameters.hport, $parameters.sport) returns the value of “$parameters.hport” if $parameters.servicetype has value “HTTP.”

Otherwise, the function returns the value of “$parameters.sport.”

Example 3:

if-then-else($parameters.servicetype == HTTP, 80) returns “80” if $parameters.servicetype has value “HTTP.”

Otherwise, the function does not return any value.

join()

The join() function takes two arguments:

Argument 1: list of numbers, tcp-ports, strings, or ipaddresses

Argument 2: delimiter string (optional)

The function joins the elements of the list provided as argument one into a string, where each element is separated by the delimiter string provided as argument two. If argument two is not provided, then elements in the list are joined together as one string.

Example:

  • $parameters.ports is [81, 82, 83].

    • With delimiter argument:

      join($parameters.ports, ‘-‘) returns “81-82-83”

    • Without delimiter argument:

      join($parameters.ports) returns “818283”

split()

The split() function splits an input string into multiple lists depending on the specified separators. If no or blank ('') separator is specified, this function considers space as a separator and splits the string into lists.

Examples:

  • The split('Example_string_split', 's') function returns ['Example_','tring_','plit'].

  • The split('Example string split') function returns ['Example','string','split'].

  • The split('Example string split', '') function returns ['Example','string','split'].

  • The split('Example string') function returns ['Example','string'].

    This function considers continuous spaces as one space.

map()

The map function takes two arguments;

Argument 1: Any function

Argument 2: A list of elements.

The function returns a list where each element in the list is the result of applying the mapfunction (argument one) to the corresponding element in argument two.

Allowed functions in argument 1:

  • Built-in functions that take one argument:

    base64.encode, base64.decode, bin, bool, exists, hex, int, ip, len, lower, upper, oct, quotewrap, str, trim, upper, url.encode, url.decode

  • Substitution functions that take at least one argument.

Example:

Suppose $parameters.nums is [81, 82, 83].

  • Map using a built-in function, str

    map(str, $parameters.nums) returns [“81”, “82”, “83”]

    The result of the map function is the list of strings where each element is string is computed by applying the str function on the corresponding element in the input list ($parameters.nums).

  • Map using a substitution function

    • Substitutions:

      add-10(port): $port + 10

    • Expression:

      map($substitutions.add-10,

      $parameters.nums) returns a list of numbers: [ 91, 92, 93 ]

The result of this map function is a list of numbers, each element is computed by applying the substitution function $substitutions.add-10 on the corresponding element in the input list ($parameters.nums).

quotewrap()

The quotewrap function takes a string as argument and returns a string after adding double quote character before and after the input value.

Example:

quotewrap(“mas”) returns ““mas””

replace()

The replace function takes three arguments:

Argument 1: string

Argument 2: string

Argument 3: string (optional)

The function replaces all the occurrences of argument two with argument three in argument one.

If argument three is not provided, all occurrences of argument two are removed from argument one (in other words, replaced with empty string).

Replace a substring with another substring:

  • replace(‘abcdef’, ‘def’, ‘xyz’) returns “abcxyz”.
    • All occurrences of “def” are replaced by “xyz”.
  • replace(‘abcdefabc’, ‘def’) returns “abcabc”.
    • As there is no third argument, “def” is removed from the resulting string.

replace()

The replace() function takes three arguments:

Argument 1: string

Argument 2: string or list

Argument 3: string (optional)

The function replaces all the occurrences of argument two with argument three in argument one.

If argument three is not provided, all occurrences of argument two are removed from argument one (in other words, replaced with an empty string).

Replace a substring with another substring:

  • The replace('abcdef', 'def', 'xyz') function returns abcxyz.

    All occurrences of def are replaced with xyz.

  • replace('abcdefabc', 'def') returns abcabc.

    As there is no third argument, def is removed from the resulting string.

Specify the characters list that you want to replace in a string.

$parameters.spl_chars = ['@', '#', '!', '%']

This list contains the values that have to be replaced in an input string.

The replace('An#example@to%replace!characters', $parameters.spl_chars, '_') function returns An_example_to_replace_characters.

The output string has underscore (_) instead of characters specified in the $parameters.spl_chars list.

trim()

The trim function returns a string where the leading and trailing whitespaces are stripped from the input string.

Example:

trim(‘ abc ‘) returns “abc”

truncate()

The truncate function takes two arguments:

Argument 1: string

Argument 2: number

The function returns a string where the input string in argument one is truncated to the length specified by argument two.

Example:

truncate(‘netscaler mas’, 9) returns “netscaler”

distinct()

The distinct() function extracts unique items from a list input.

Examples: $parameters.input_list = ['ADM', 'ADC', 'VPX', 'ADC', 'ADM', 'CPX']

The distinct($parameters.input_list) function returns ['ADM', 'ADC', 'VPX', 'CPX'].

url.encode

The url.encode function returns a string where characters are transformed using ASCII character set according to RFC 3986.

Example:

url.encode(“a/b/c”) returns “a%2Fb%2Fc”

url.decode

The url.decode function returns a string where the URL encoded argument is decoded in to a regular string according to RFC 3986.

Example:

url.decode(“a%2Fb%2Fc”) returns “a/b/c”

is-ipv4()

The is-ipv4() function takes an IP address as an argument and returns the boolean True if the IP address is of the IPv4 format.

The is-ipv4(10.10.10.10) function returns True

is-ipv6()

The is-ipv6() function takes an IP address as an argument and returns the boolean True if the IP address is of the IPv6 format.

The is-ipv6(2001:DB8::) function returns True

startswith()

The startswith() function determines whether a string begins with a given prefix. This function requires two mandatory string arguments.

startswith(str, sub_str)

This function returns True when the string (str) starts with the substring (sub_str).

Example:

  • startswith('Citrix', 'Ci') - returns True
  • startswith('Citrix', 'iC') - returns False
  • startswith('Citrix', 'Ab') - returns False

endswith()

The endswith() function determines whether a string ends with a given suffix. This function requires two mandatory string arguments.

endswith(str, sub_str)

This function returns True when the string (str) ends with the substring (sub_str).

Example:

  • endswith('Citrix', 'ix') - returns True
  • endswith('Citrix', 'Ix') - returns False
  • endswith('Citrix', 'ab') - returns False

contains()

The contains() function determines whether a string contains a given substring. This function requires two mandatory string arguments.

contains(str, sub_str)

This function returns True when the substring (sub_str) is contained anywhere inside the string (str).

Example:

  • contains('Citrix', 'tri') - returns True
  • contains('Citrix', 'Ci') - returns True
  • contains('Citrix', 'ti') - returns False

substring()

Use the substring() function to extract a substring from a string.

substring(str, start_index, end_index)

This function requires the two mandatory arguments and one optional integer argument.

  • str (Mandatory)
  • start_index (Mandatory)
  • end_index (Optional)

This function returns the substring from the string (str) that is between the specified index positions. If you do not specify the end index position, the function extracts the substring from the start index to the end of the string.

Note

When you specify end_index, the substring excludes the character at the end_index position.

Example:

  • substring('Citrix', 2) - returns trix

  • substring('Citrix', 10) - returns (")

    In this example, the function returns a blank string. The start_index position is invalid.

  • substring('Citrix', 2, 4) - returns tr

    In this example, the function extracts the characters between 2 and 4 index positions.

  • substring('Citrix', -3) - returns rix

    If you want to extract characters that are at the end of the string, specify a negative value for the start_index argument.

    In this example, the function extracts the substring that includes the last three characters in the string.