Parameters and examples for miscellaneous functions - CDN

This page covers utility functions available in EdgeScript: encoding and decoding, random number generation, checksums, type conversion, and unique identifier generation.

Base64 encoding and decoding

EdgeScript provides two Base64 variants: standard Base64 (base64_enc / base64_dec) and URL-safe Base64 (base64_enc_safe / base64_dec_safe). Use the standard variant for general encoding; use the URL-safe variant when the encoded string appears in URLs or HTTP headers.

base64_enc

Encodes a string using standard Base64 encoding.

Syntax

base64_enc(s [, no_padding])

Parameters

Parameter	Description
`s`	The string to encode.
`no_padding`	Specifies whether to omit padding characters. Set to `true` to remove trailing `=` characters. Default: `false`.

Return value

Returns a Base64-encoded string.

Example

if $http_data {
  decdata = base64_dec($http_data)
  say(concat('base64_decdata=', decdata))
  say(concat('base64_encdata=', base64_enc('hello, dsl')))
}

Request header: data: aGVsbG8sIGRzbA==

Output:

base64_decdata=hello, dsl
base64_encdata=aGVsbG8sIGRzbA==

base64_dec

Decodes a Base64-encoded string.

Syntax

base64_dec(s)

Parameters

Parameter	Description
`s`	The Base64-encoded string to decode.

Return value

Returns the decoded raw string.

Example

if $http_data {
  decdata = base64_dec($http_data)
  say(concat('base64_decdata=', decdata))
  say(concat('base64_encdata=', base64_enc('hello, dsl')))
}

Request header: data: aGVsbG8sIGRzbA==

Output:

base64_decdata=hello, dsl
base64_encdata=aGVsbG8sIGRzbA==

base64_enc_safe

Encodes a string using URL-safe Base64 encoding. In the output, + is replaced by -, / is replaced by _, and = padding characters are removed.

Syntax

base64_enc_safe(str)

Parameters

Parameter	Description
`str`	The string to encode.

Return value

Returns a URL-safe Base64-encoded string.

Example

add_rsp_header('X-RESPOND-OUTPUT', concat('base64_enc_safe=', base64_enc_safe('hello, dsl')), true)

Response header:

X-RESPOND-OUTPUT: base64_enc_safe=aGVsbG8sIGRzbA

base64_dec_safe

Decodes a URL-safe Base64-encoded string. Before decoding, - is replaced by + and _ is replaced by /. Padding characters (=) are appended as needed to make the string length a multiple of four.

Syntax

base64_dec_safe(str)

Parameters

Parameter	Description
`str`	The URL-safe Base64-encoded string to decode.

Return value

Returns the decoded raw string.

Example

add_rsp_header('X-RESPOND-OUTPUT', concat('base64_dec_safe=', base64_dec_safe(base64_enc_safe('hello, dsl'))), true)

Response header:

X-RESPOND-OUTPUT: base64_dec_safe=hello, dsl

URL encoding and decoding

url_escape

Encodes a string using URL encoding (percent-encoding).

Syntax

url_escape(s)

Parameters

Parameter	Description
`s`	The string to encode.

Return value

Returns a URL-encoded string.

Example

raw = '/abc/123/ dd/file.m3u8'
esdata = url_escape(raw)
dsdata = url_unescape(esdata)
if eq(raw, dsdata) {
  say(concat('raw=', raw))
  say(concat('dsdata=', dsdata))
}

Output:

raw=/abc/123/ dd/file.m3u8
esdata=%2Fabc%2F123%2F%20dd%2Ffile.m3u8
dsdata=/abc/123/ dd/file.m3u8

url_unescape

Decodes a URL-encoded string.

Syntax

url_unescape(s)

Parameters

Parameter	Description
`s`	The URL-encoded string to decode.

Return value

Returns the decoded raw string.

Example

raw = '/abc/123/ dd/file.m3u8'
esdata = url_escape(raw)
dsdata = url_unescape(esdata)
if eq(raw, dsdata) {
  say(concat('raw=', raw))
  say(concat('dsdata=', dsdata))
}

Output:

raw=/abc/123/ dd/file.m3u8
esdata=%2Fabc%2F123%2F%20dd%2Ffile.m3u8
dsdata=/abc/123/ dd/file.m3u8

Random number generation

randomseed

Initializes the random number generator. Call this before rand to ensure different random sequences across requests.

Syntax

randomseed()

Parameters

None.

Return value

None.

Example

randomseed()
r = rand(1, 100)

rand

Returns a random number within a specified range (inclusive).

Syntax

rand(n1, n2)

Parameters

Parameter	Description
`n1`	The lower bound.
`n2`	The upper bound.

The returned value satisfies n1 <= result <= n2.

Return value

Returns a random number.

Example

r = rand(1, 100)

rand_hit

Returns true or false based on the specified probability. Use this to implement percentage-based traffic splitting or feature rollouts.

Syntax

rand_hit(ratio)

Parameters

Parameter	Description
`ratio`	The probability of returning `true`. Valid values: 0–100. A value of `100` always returns `true`; a value of `0` always returns `false`.

Return value

Returns true or false.

Example

rand_hit(80)

rand_bytes

Generates a random numeric string of the specified length.

Syntax

rand_bytes(len)

Parameters

Parameter	Description
`len`	The length of the random numeric string to generate.

Return value

Returns the generated random numeric string.

Example

rand_bytes(16)

Checksum

crc

Calculates a Cyclic Redundancy Check (CRC) value for a string.

Syntax

crc(s)

Parameters

Parameter	Description
`s`	The string for which to calculate the CRC value.

Return value

Returns the CRC value of the input string.

Example

crc('hello edgescript')

Type conversion

tonumber

Converts a string to a numeric type.

Syntax

tonumber(s [, base])

Parameters

Parameter	Description
`s`	The string to convert.
`base`	The base for numeric conversion. Valid values: `10` (decimal) and `16` (hexadecimal). Default: `10`.

Return value

Returns a number.

Example

n = tonumber('100')
say(concat('tonumber()=', n))

Output:

tonumber()=100

Unique identifier

uuid

Returns a randomly generated UUID string.

Syntax

uuid()

Parameters

None.

Return value

Returns a UUID string. Example: 16903a86-4173-4dea-842c-926c5860fe05.

Example

say(uuid())

Output:

16903a86-4173-4dea-842c-926c5860fe05