Module: SecureRandom

Defined in:
lib/opal_patches.rb

Defined Under Namespace

Classes: EntropyError

Class Method Summary collapse

Class Method Details

.base64(n = 16) ⇒ Object 



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# File 'lib/opal_patches.rb', line 496

def self.base64(n = 16)
  require "base64"
  Base64.strict_encode64(random_bytes(n))
end

.hex(n = 16) ⇒ Object 



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# File 'lib/opal_patches.rb', line 480

def self.hex(n = 16)
  n = n.to_i
  n = 16 if n <= 0
  out = secure_hex_bytes(n)
  if out.nil?
    raise EntropyError,
          "no source of cryptographic entropy available (node:crypto AND Web Crypto both unreachable)"
  end
  out
end

.random_bytes(n = 16) ⇒ Object 



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# File 'lib/opal_patches.rb', line 469

def self.random_bytes(n = 16)
  n = n.to_i
  n = 16 if n <= 0
  hex_string = secure_hex_bytes(n)
  if hex_string.nil?
    raise EntropyError,
          "no source of cryptographic entropy available (node:crypto AND Web Crypto both unreachable)"
  end
  [hex_string].pack("H*")
end

.secure_hex_bytes(n) ⇒ Object

Returns a hex string of ‘n` random bytes, or nil when no entropy source is available. Tries node:crypto.randomBytes first (works on both Cloudflare Workers with `nodejs_compat` and Node.js), falls back to Web Crypto getRandomValues (works at request time on Workers and everywhere on browsers).



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# File 'lib/opal_patches.rb', line 518

def self.secure_hex_bytes(n)
  # Opal does not always auto-return backtick IIFEs; assign first
  # so the method's last expression is a normal Ruby reference.
  result =
    `(function(n) {
    try {
      if (typeof globalThis.__nodeCrypto__ !== 'undefined' && globalThis.__nodeCrypto__) {
        return globalThis.__nodeCrypto__.randomBytes(n).toString('hex');
      }
    } catch (e) { /* fall through to Web Crypto */ }
    try {
      if (typeof crypto !== 'undefined' && crypto.getRandomValues) {
        var bytes = new Uint8Array(n);
        crypto.getRandomValues(bytes);
        var out = '';
        for (var i = 0; i < bytes.length; i++) {
          var h = bytes[i].toString(16);
          if (h.length < 2) h = '0' + h;
          out += h;
        }
        return out;
      }
    } catch (e) {
      // Workers blocks getRandomValues at module-load scope; fall through.
    }
    return nil;   // Opal nil singleton, not JS null — so .nil? works
  })(#{n})`
  result
end

.urlsafe_base64(n = 16, padding = false) ⇒ Object 



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# File 'lib/opal_patches.rb', line 501

def self.urlsafe_base64(n = 16, padding = false)
  s = base64(n).tr("+/", "-_")
  padding ? s : s.delete("=")
end

.uuid ⇒ Object 



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# File 'lib/opal_patches.rb', line 491

def self.uuid
  h = hex(16)
  "#{h[0, 8]}-#{h[8, 4]}-4#{h[13, 3]}-#{h[16, 4]}-#{h[20, 12]}"
end