GenerateShortGUID() - generate a 8-byte, URL-safe ID for slightly saner URLs with a very low collision chance (http://goo.gl/VWAFOo) and avoid http://example.com/thing/550e8400-e29b-41d4-a716-446655440000 ugliness. Leverages Go's existing cryptographically secure random number generator: http://elithrar.github.io/article/generating-secure-random…

helpers.go

// GenerateRandomBytes generates a crytographically secure random byte string using crypto/rand.
func GenerateRandomBytes(s int) ([]byte, error) {
	b := make([]byte, s)
	n, err := rand.Read(b)
	if n != len(b) || err != nil {
		return nil, fmt.Errorf("Unable to successfully read from the system CSPRNG (%v)", err)
	}

	return b, nil
}

// GenerateRandomString generates a crytographically secure, URL-safe base64-encoded string.
func GenerateRandomString(s int) (string, error) {
	b, err := GenerateRandomBytes(s)
	if err != nil {
		return "", err
	}

	return base64.URLEncoding.EncodeToString(b), nil
}

// GenerateShortGUID generates an 8-byte short pseudo-GUID and returns a URL-safe base64-encoded string.
// Note: Collision chance (birthday paradox) is approx. .000000002% after 100,000 GUIDs.
// See http://goo.gl/VWAFOo for more details.
func GenerateShortGUID() (string, error) {
	id, err := GenerateRandomString(8)
	if err != nil {
		return "", err
	}

	return id, nil
}