This just provides some helper methods for both token classes to use

This will create a randomly generated 20-character token for use as a request or access token. The string is hexadecimal.

This does not check for uniqueness.

This does some checks and provides some defaults.

It tries a number of times to create a unique token using generate_token. If that fails, this method will DIE.

It will also create a secret using generate_token.

Finally, it will create a default valid_until of 1 hour from now.