[JAMES-3657] WebAdmin: refactor entity validation upon creation

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.7.0
• Fix Version/s: 3.7.0
• Component/s: webadmin
• Assignee: Unassigned
• Reporter: Benoit Tellier
• Created: 01/Oct/21 02:10
• Updated: 08/Oct/21 02:29
• Resolved: 08/Oct/21 02:29

Description

Why?

James currently lacks some validation logic to ensure that when creating a new entity, it does not clash with existing entities having the same mail address in the system (users, aliases, groups, ...). To validate them, we could implement validation for each of them in each of them (O(n^2)) wich is both not extensible and not scalable.

Instead, our proposed approach would be to just write n validators (O), so one for each, and plug all of them into one aggregator, that the different routes managing concerned entities would check. Adding 1 entity would require only writing 1 validator then.

How?

So, we could create a new interface called `UserEntityValidator` that would return a `ValidationResult` defined to hold if an entity exists or not and the nature of the entity:
```
interface ValidationResult

{ boolean asBool(); String entityName(); }

class SuccessValidationResult extends ValidationResult

{ ... }
class FailureValidationResult extends ValidationResult { ... }

interface UserEntityValidator

{ ValidationResult exists(Username username); }

```

Then we could have implementations of this validator for each entity in the system: users, aliases, groups:
```
class AliasUserEntityValidator extends UserEntityValidator

{ ... }
class GroupUserEntityValidator extends UserEntityValidator { ... }

class AccountUserEntityValidator extends UserEntityValidator

{ ... }
```

Finally we would multi-bind them all into an aggregate implementation `AggregateUserEntityValidator`:
```
// This is the implementation we rely on, in every routes.
class AggregateUserEntityValidator extends UserEntityValidator {
// All validators, for all entotoes, including extensions, managed by Guice.
private final Set<UserEntityValidator> validators;

@Inject
AggregateUserEntityValidator(Set<UserEntityValidator> validators) { this.validators = validators; }

public ValidationResult exists(Username username) { ... }

}
```

Definition of done

Finally, we would need to answer the following cases regarding the tests:

```
GIVEN a user [e-mail]
WHEN I create the user [e-mail]
THEN it fails
```

```
GIVEN an alias [e-mail]
WHEN I create the user [e-mail]
THEN it fails
```

```
GIVEN a group [e-mail]
WHEN I create the user [e-mail]
THEN it fails
```

```
GIVEN a user [e-mail]
WHEN I create the alias [e-mail]
THEN it fails
```

```
GIVEN an alias [e-mail]
WHEN I create the alias [e-mail]
THEN it fails
```

```
GIVEN a group [e-mail]
WHEN I create the alias [e-mail]
THEN it fails
```

```
GIVEN a user [e-mail]
WHEN I create the group [e-mail]
THEN it fails
```

```
GIVEN an alias [e-mail]
WHEN I create the group [e-mail]
THEN it fails
```

```
GIVEN a group [e-mail]
WHEN I create the group [e-mail]
THEN it fails
```

Reference to a previous proposal

https://www.mail-archive.com/[e-mail]/msg71116.html

Issue Links

• links to: GitHub Pull Request #678
• links to: GitHub Pull Request #681