Re: Modeling the user registration process

http://caminao.wordpress.com/how-to-implement-symbolic-representations/patterns/functional-patterns/users/


On 8 July 2013 23:45, Guillaume Bilodeau <[email protected]>wrote:

> **
>
>
> Hi all,
>
> I'm looking for some basic feedback on the very standard user registration
> process. Here we go.
>
> Domain
> ======
> . In order to access some restricted features of the application, a person
> needs to create an account for the application.
> . During this registration process, the person enters his full name, his
> email address, a password of his choice and, optionally, a profile photo.
>   A thumbnail of the profile photo must be presented to other users in
> various situations.
> . At this point, the person cannot yet log in using his email address and
> password.
> . The person's email address must then be verified. A random alphanumeric
> token is generated and sent to the person's email address, along with an
> application URL.
> . The person then opens this application URL and enters the given token.
>   In case of a match, the person's email is considered verified and his
> account is activated.
>   The person can now login with his email address and password.
>
> Design
> ======
> The following packages, classes and resources have been created.
> Interfaces are marked by (I), classes by (C), enums by (E) and files by (F).
>
> com.company.project.commons.media
> (I) ThumbnailProducer
> (C) AwtThumbnailProducer
>
> com.company.project.application.user
> (I) UserAccountService
> (C) UserAccountServiceImpl
>
> com.company.project.application.user.verification
> (C) EmailVerificationTokenMailer
> (C) MailingTokenEmailVerificationStrategy
> (I) TokenBasedEmailVerificationStrategy
> (F) registration_html_en.template
> (F) registration_text_en.template
>
> com.company.project.domain.token
> (C) InvalidTokenException
> (C) RandomAlphanumericTokenFactory
> (C) Token
> (I) TokenFactory
> (I) TokenRepository
> (E) TokenType
>
> com.company.project.domain.user
> (I) ProfilePhotoRepository
> (C) ProfilePhotoThumbnailProducer
> (C) UserAccount
> (C) UserAccountBuilder
> (C) UserAccountRegistrationRequest
> (C) UserAccountRegistrationService
> (I) UserAccountRepository
> (E) UserAccountStatus
>
> com.company.project.infrastructure.persistence
> (C) DelegatingProfilePhotoRepository
> (I) MediaStorage
>
> com.company.project.infrastructure.persistence.filesystem
> (C) LocalFileSystemMediaStorage
>
> com.company.project.infrastructure.persistence.jpa
> (C) JpaTokenRepository
> (C) JpaUserAccountRepository
>
> com.company.project.web.user
> (C) UserAccountRegistrationController
> (C) UserAccountEmailVerificationController
>
> Technical constraints
> =====================
> This application is developed using a common Java stack: Spring MVC,
> Spring IoC, Spring Security, JPA / Hibernate with a relational Postgres
> database.
> Profile photos are to be stored on a locally accessible network area
> storage.
>
> Explanations
> ============
> . UserAccountService/Impl is an application service that manages
> everything related to user management.
> . UserAccount is a domain entity.
> . UserAccountRegistrationRequest is a (mutable) value object that
> represents the registration request.
> . UserAccountBuilder is a domain service that builds a UserAccount from
> this UserAccountRegistrationRequest.
> . UserAccountRepository is a domain repository that manages UserAccount
> persistence. Its implementing JpaUserAccountRepository is an infrastructure
> service.
> . There is no ProfilePhoto domain object.
> . ProfilePhotoRepository is a domain repository that manages profile photo
> persistence and lookup. Its implementing DelegatingProfilePhotoRepository
> is an infrastructure service.
>   DelegatingProfilePhotoRepository delegates these operations to
> MediaStorage and its implementing LocalFileSystemMediaStorage. Methods deal
> in byte[] and URLs.
> . ProfilePhotoThumbnailProducer is a domain service that produces
> thumbnails of a given profile photo's byte[] using a ThumbnailProducer and
> its implementing AwtThumbnailProducer.
> . UserAccount maintains references to his full-size and thumbnail-sized
> profile photos using URLs produced by the ProfilePhotoRepository.
> . UserAccountRegistrationService is a domain service that manages the
> registration process. Invoked by UserAccountServiceImpl.
> . Token is a domain entity. Token has a UserAccount owner; UserAccount has
> no knowledge of the tokens he owns.
> . TokenFactory is a domain factory. It produces Token instances.
> RandomAlphanumericTokenFactory is a TokenFactory that uses a random
> algorithm to achieve this.
> . TokenRepository is a domain repository that manages Token persistence.
> Its implementing JpaTokenRepository is an infrastructure service.
> . TokenBasedEmailVerificationStrategy is an application service that
> manages email verification. MailingTokenBasedEmailVerification implements
> this interface by
>   producing a Token, assigning it to its UserAccount owner, and sending it
> to the owner through the EmailVerificationTokenMailer. It also verifies the
> later-submitted Token.
> . EmailVerificationTokenMailer produces the email message using the
> registration_html_en.template and registration_text_en.template templates.
> It then sends them using the JavaMail API.
>
> Questions
> =========
> I think that this is an adequate model. However, I would like some
> feedback.
>
> 1. Should there be a UserAccount entity at all? Or just a User / Person /
> Party / Actor entity?
> 2. How does the packaging look like?
> 3. Am I completely lost when it comes to distinguishing application vs
> domain vs infrastructure services?
> 4. What does the (Delegating)ProfilePhotoRepository to
> (LocalFileSystem)MediaStorage strategy look like?
> 5. Should there be a ProfilePhoto domain object?
> 6. Is MailingTokenBasedEmailVerification really an application service? Or
> should it be considered a domain service?
> 7. Is EmailVerificationTokenMailer an application, domain or service or
> infrastructure service? It looks like an application process, but it speaks
> of domain entities and integrates
>    with the mailing infrastructure. Not clear to me what this is. I
> consider the JavaMail API to be the infrastructure service here.
>
> Any feedback would be greatly appreciated :)
>
> Thanks a bunch!
>
>  
>