Utils

Here you can find various helpers available in the root core namespace.

log

Prints a string message to the /usr/local/coronium/logs/coronium.log file.

core.log( message )

Parameters

Name	Description	Requried
message	The message string to log.	Y

Example

core.log('something to log')

sf (string format)

Format a string based on token replacment. This method shares the same attributes as the Lua string.format method.

core.sf( str_template, values )

Parameters

Name	Description	Requried
str_template	The string containing replacment tokens.	Y
values	A list of values for token replacment.	Y

Example

local username = "Dave"
local formatted_str = core.sf("Hello, %s!", username)

-- formatted_str = "Hello, Dave!"

Notes

Some common token types:

Token	Description
%s	Used as a string replacment, any other type will error.
%d	Used as a number replacment, any other type will error.

You can mix tokens, as well as have multiples:

local str = core.sf("Ordered %d %s with %s.", 2, 'burgers', 'cheese')
-- `str` contains "Ordered 2 burgers with cheese."

Tip

The sf method is useful for creating SQL queries, as well as other type-safe replacments.

trim

Removes empty space from the start and end of a string, if any.

core.trim( string )

Parameters

Name	Description	Requried
string	The string to trim.	Y

Example

local trimmed_str = core.trim("  I could use a trim  ")

-- trimmed_str = "I could use a trim"

split

Converts a delimited string into a Lua table array.

core.split( string[, delimiter ] )

Parameters

Name	Description	Default	Requried
string	The delimited string to split.	None	Y
delimiter	The delimiter to split the string with.	Comma ( , )	N

Example

local tbl_array = core.split("Red,Green,Blue")

-- `tbl_array` contains {"Red","Green","Blue"}

Using a custom delimiter:

local tbl_array = core.split("User:2001:Storage", ":")

-- `tbl_array` contains {"User","2001","Storage"}

json

JSON encoding and decoding.

local json = core.json

Encode

local str = json.encode(tbl)

Decode

local tbl = json.decode(str)

json_safe

JSON encoding and decoding with error handling.

local json = core.json_safe

Encode safe

local str, err = json.encode(tbl)

Decode safe

local tbl, err = json.decode(str)

uuid

Generates a universally unique id.

Example

local uuid = core.uuid()

-- `uuid` will contain something like "1f0af2fa-8b06-4605-bace-e13a85aa36d5"

md5

Generate a hexadecimal MD5 digest from a given string.

local md5 = core.md5("somestringtomd5")

-- `md5` will contain something like "9a5c03309269f0274506259626dc725c"

sleep

Pause processing for a certain amount of seconds. Useful in looping situations.

core.sleep(seconds)

Parameters

Name	Description	Default	Requried
seconds	The amount of seconds to sleep.	Number	Y

Example

for i=1, 20 do
  --do some work

  core.sleep(2) --wait 2 seconds
end

countryCode

Two letter country code based on the request IP. Can only be called in a core.api method.

Example

local code = core.countryCode()

-- `code` will contain something like "US" or "EU"

callApi

Call a method on a custom api endpoint built using the core.api. This method allows you to call other project api methods from within a different project api.

core.callApi(project, action, data_params)

Parameters

Name	Description	Type	Required
project	The name of the api project.	String	Y
action	The name of the api method to call.	String	Y
data_params	Values to pass to the api method.	Table	Y

Example

local result, err = core.callApi("default", "test", {greet="Hello!"})