Utility Macros

In addition to the core and HTTP macros, ngrok provides a set of utility macros within the Traffic Policy engine. These macros are typically available across all phases, unless otherwise specified.

Name	Return Type	Description
inCidrRange(ip,cidr)	bool	Returns true or false if the provided IP address falls within the provided CIDR range. Returns false if the provided CIDR range is invalid.
inCidrRanges(ip,cidrs)	bool	Returns true or false if the provided IP address falls within any of the provided CIDR ranges. Ignores any provided CIDR ranges that are invalid.
rand.double()	double	Returns a random double between 0 and 1.
rand.int(min,max)	int	Returns a random int between the provided min and max values. Only supports positive integers and min must be larger than the provided max. By default, min is 0 and max is 1.

inCidrRange(ip,cidr) → bool

Evaluates whether the given IP address falls within the specified CIDR range.

Returns true if the IP is within the range, and false if it is outside the range or if the provided CIDR is invalid.

Example

inCidrRange('192.168.1.100', '192.168.1.0/24')  // true

Example (in expression)

YAML

# snippet
---
expressions:
  - "inCidrRange(conn.client_ip, '66.249.66.1/24')"

JSON

// snippet
{
  "expressions": [
    "inCidrRange(conn.client_ip, '66.249.66.1/24')"
  ]
}

inCidrRanges(ip,cidrs) → bool

Checks if the given IP address falls within any of the specified CIDR ranges.

Returns true if the IP is within at least one valid CIDR range, and false if it is not within any valid range. Invalid CIDR ranges are ignored.

Example

inCidrRanges('192.168.1.100', ['192.168.1.0/24', '10.0.0.0/8']) // true

Example (in expression)

YAML

# snippet
---
expressions:
  - "inCidrRanges(conn.client_ip, ['66.249.66.1/24', '2001:4860::/32'])"

JSON

// snippet
{
  "expressions": [
    "inCidrRanges(conn.client_ip, ['66.249.66.1/24', '2001:4860::/32'])"
  ]
}

rand.double() → double

Returns a random double between 0 and 1.

Example

rand.double() >= 0.5

Example (in expression)

YAML

# snippet
---
expressions:
  - "rand.double() >= 0.5"

JSON

// snippet
{
  "expressions": [
    "rand.double() >= 0.5"
  ]
}

rand.int(min,max) → int

Returns a random int between the provided min and max values. Only supports positive integers and min must be larger than the provided max. By default, min is 0 and max is 1.

Example

rand.int() == 1
rand.int(0, 10) >= 5

Examples (in expression)

The following is an example of using rand.int with the default values:

YAML

# snippet
---
expressions:
  - "rand.int() == 1"

JSON

// snippet
{
  "expressions": [
    "rand.int() == 1"
  ]
}

The following is an example of using rand.int with custom values:

YAML

# snippet
---
expressions:
  - "rand.int(0, 10) >= 5"

JSON

// snippet
{
  "expressions": [
    "rand.int(0, 10) >= 5"
  ]
}