@flexdemo/utils

FlexDeMo-Module-Utils

This Package contains serveral Utilities that are designed to make Backend Development more efficient.

Content

• Logging
• Configuration
• Messaging Utils
• Password Validator
• JWT Utils
• Exceptions

Logging

The Logging utility can be accessed via the logger object. To use it, simply call on of the following:

• logger.error(message:string)
• logger.warning(message:string)
• logger.info(message:string)
• logger.debug(message:string)

Configuration

This Module provides a way to easily provide a hot-swappable Configuration to another module. To use the Configuration, first one needs to create the Configuration File appconfig.json in the Root of the NodeJS Project. Then it can be loaded via the Configuration Class. To initialize the Configuration Class one needs to initialize a new Object of the class an call initialize. After the returned Promise is resolved, the Configuration can be accessed via Configuration.Configuration.

File Watcher

initialize will also start a File watcher on the Configuration file. When the File is Changed, the Configuration Object is reloaded from the Configuration File. To stop the file watcher, for example to end Tests one can use Configuration.dispose(). dispose is an async function that will resolved once the File Watcher is completely disabled.

Messaging Utils

Error Message Utils

The Class ErrorMessageUtils contains Utils that can be used to check and create ErrorMessage Objects that can be used in the Communication Middleware. The static Method IsErrorMessage(message) can be used to determine if the message is a ErrorMessage. The Methods:

• GetNotAllowedError(message)
• GetNotAuthorized(message)
• BadRequest(message)
• GetNotImplemented()

can be used to create ErrorMessages of the specified Type (please refer to the Communication Protocol Documentation).

Password Validator

The Password Validator is an easy Tool to handle Password Validation. It is mostly composed out of the auth0 password-sheriff and dumb-passwords npm Packages. It can be easaly configured via the Configuration Utils. The Password Validator can be created by using the new PasswordValidator() construktor.

Pasword Validation

To Validate a Password first create a new Instance of the PasswordValidator. Then call the ValidatePassword(password, passwordRules) Method, where password is the Password that should be validated, and passwordRules is the Configuration Object. The Method will return (void) when the Password is accepted, and throw a PasswordInvalidException with a message and a German displayMessage to show the User.

Password Rules

The Configuration Object can be assembled out of all options. All Options are Optional.

{
   minLength: number, //The minimal Length of the Password
   maxLength: number, //The Maximal Length of the Password (should not be set, unless for Attack Protektion of long strings)
   requiresSpecial: boolean, //Passwords need a Special Char (see https://owasp.org/www-community/password-special-characters)
   requireUpper: boolean, //Passwords needs a Upper Case Letter
   requireLower: boolean, //Password needs a Lower Case Letter
   requiresNumbers: boolean, //Password needs a Numerical Charecter
   checkIfCommon: boolean //Checks the password against a table of the 10000 most common Passwords
}

JWTUtils

This Modules Provides Utils (in form of a small Wrapper) to Provide JWT Token Generation and Validation functionality

Generate

The async JwtUtils.Generate(data, secrets, options) function can be used to Generate a JWT Token.

The Parameter data can be used to supply the Data that will be send to the client. This Data ist not Encrypted!

The Parameter secrets is a Dictionary of Keys. A Random supplied Key is used and encoded in the kid header field. Example:

  let secrets = {
      "112eab91-6226-4000-a698-bb11f613dd74": "vkmZJW4%1%y1GXt*",
      "7dfc20a0-313a-4a3f-91e9-583f4f844e7c": "#%5qz3P!QZ@YrT6T"
  };

The Parameter options contains multiple parameters that should be set! options.expiresIn contains a number with seconds or a string with a timeframe in witch the Token will be valid. Examples: 60, "1h", "2 days" options.audience is a String to set the audience the token was generated for. options.issuer is the name of the issuing Service (For example "FlexDeMo - Auth") options.subject is the Subject this Token was created for. This will be the tenantId.

The function Returns a Promise that can resolve to a String, null or Error.

Validate

The function JwtUtils.Validate(token, secrets, audience) validates a JWT Token.

The Parameter token is a String that contains the JwtToken.

The Parameter secrets is a Dictionary of Keys. The Key will be determined by the kid claim of the Token. Example:

  let secrets = {
      "112eab91-6226-4000-a698-bb11f613dd74": "vkmZJW4%1%y1GXt*",
      "7dfc20a0-313a-4a3f-91e9-583f4f844e7c": "#%5qz3P!QZ@YrT6T"
  };

The Parameter audience is an array of Strings. These contain the allowed audiences of the Service. If the aud claim of the Token does not match one of the Audiences, the Token will not be verified.

If the Token is Validated it will return a Object with a header, payload and signature field. Where the Payload is the encoded data. If the Token is not Validated, it will throw a NotAuthenticatedException;

By default, the token validation is heavily logged. The Log Level can be changed by setting the AUTH_LOGGER_LEVEL ENV var to one of the default levels of winston.

Validation Logging can be completely turned off by setting the AUTH_LOGGER_SLIENT Env var to true.

JwtAuthData

JwtAuthData is a Class that capsules the currently send data in neat and tidy way. To use it, the Token first needs to be validated. This can be archived by usage of the JwtUtils. Then the validated resultes can be passed to the constructor of JwtAuthData to create the wrapper object

let authData = new JwtAuthData(JwtUtils.Validate(token, secrets, audience));

The instance has the following attributes that can be read:

• AuthType The Type of Authentification used. Should be "jwt"

• Algorithm The Hashing Algorithem used

• TokenKeyId The Key Id that was used while creating this Token. Primarely Used to retrive the correct Password

• User The User Object

• User.id UUID v4 that identifies the User

• User.roles Array of UUID v4 that identifies all Roles this user has for this Application

• User.tenantRoles Array of UUID v4 that identifies all Roles this user has for the Tenantdata

• IssuedAt The Time this auth token was created at

• Expires The Time this token expires

• Audience The Aufience this token was created for

• Issuer The Issuer of the Token

• TenantId The UUIDv4 of the Tenant that this User belongs to

  Exceptions

  AlreadyExistsException

  This Exception can be thrown if an Element could not be created or changed, because an other Element already exists.

  Usage

  new AlreadyExcistsException(message, innerException) alreadyExistsException.toString() can be used to create a readable String of the exception

  ArgumentException

  This Exception can be thrown if some Argument was Missing, or if an Argument had the wrong Type or Format.

  Usage

  new ArgumentException(parameterName, parameterValue) argumentException.toString() can be used to create a readable String of the exception;

  BadRequestException

  This Exception can be thrown if a Communication Middleware returns a Bad Request Event.

  Usage

  new BadRequestException("Cold not call Auth Middleware", error) exception.toString() can be used to create a readable String of the exception;

  ConfigurationException

  This Exception can be thrown if the ApplicationConfiguration is malformed or Contains errors.

  Usage

  new ConfigurationException("Missing Configuration for Data Provider URL", innerException) exception.toString() can be used to create a readable String of the exception;

  NotAuthenticatedException

  This Exception can be thrown if the user could not be authenticated. Ether as a LoginError, or because the Session Token was wrong or missing

  Usage

  new NotAuthenticatedException("Session Token Hash not valid", innerException) exception.toString() can be used to create a readable String of the exception;

  NotAuthorizedException

  This Exception can be thrown if the user accessed a Function or Resource for witch he is not Authorized.

  Usage

  new NotAuthorizedException("User is not allowed to view Admin Area", innerException) exception.toString() can be used to create a readable String of the exception;

  NotImplementedException

  This Exception can be thrown, if a Function is called, witch currently is not Implemented.

  Usage

  new NotImplementedException("GetUsers() not Implemented jet", innerException) exception.toString() can be used to create a readable String of the exception;

  PasswordInvalidException

  This Exception is thrown, if the PasswordValidator can not Validate the supplied Password. Has the Attribute displayMessage in wich a German string is saved, witch can be shown to the User.

  TimeoutException

  This Exception can be thrown if some Timeout was met, for example if a Response from a Request to via the ConnectionService takes to long.

  Usage

  new TimeoutException(message, innerException?) will create a new Timeout Exception. timeoutException.toString() will create a proper error String that can be displayed.