crypto = require 'crypto' # This module mirrors the token generation in Overleaf (`random_token.rb`), # for the purposes of implementing token-based project access, like the # 'unlisted-projects' feature in Overleaf module.exports = ProjectTokenGenerator = # (From Overleaf `random_token.rb`) # Letters (not numbers! see generate_token) used in tokens. They're all # consonants, to avoid embarassing words (I can't think of any that use only # a y), and lower case "l" is omitted, because in many fonts it is # indistinguishable from an upper case "I" (and sometimes even the number 1). TOKEN_ALPHA: 'bcdfghjkmnpqrstvwxyz' TOKEN_NUMERICS: '123456789' _randomString: (length, alphabet) -> result = '' crypto.randomBytes(length).map( (b) -> result += alphabet[b % alphabet.length] ) return result # Generate a 12-char token with only characters from TOKEN_ALPHA, # suitable for use as a read-only token for a project readOnlyToken: () -> return ProjectTokenGenerator._randomString( 12, ProjectTokenGenerator.TOKEN_ALPHA ) # Generate a longer token, with a numeric prefix, # suitable for use as a read-and-write token for a project readAndWriteToken: () -> numerics = ProjectTokenGenerator._randomString( 10, ProjectTokenGenerator.TOKEN_NUMERICS ) token = ProjectTokenGenerator._randomString( 12, ProjectTokenGenerator.TOKEN_ALPHA ) fullToken = "#{numerics}#{token}" return fullToken