kumo.file_type.from_bytes

local ft = kumo.file_type.from_bytes(BYTES)

Since: Dev Builds Only

The functionality described in this section requires a dev build of KumoMTA. You can obtain a dev build by following the instructions in the Installation section.

Attempts to determine the file type from the provided string, which may also be binary bytes.

This function will always succeed in returning a guess, which may or may not be accurate.

The return value is a FileTypeResult

local kumo = require 'kumo'
local utils = require 'policy-extras.policy_utils'

local ft = kumo.file_type.from_bytes '\xCA\xFE\xBA\xBE'
utils.assert_eq(ft, {
  name = 'Java class file',
  extensions = { 'class' },
  media_types = {
    'application/java',
    'application/java-byte-code',
    'application/java-vm',
    'application/x-httpd-java',
    'application/x-java',
    'application/x-java-class',
    'application/x-java-vm',
  },
})