Package io.vertx.ext.auth

## Interface User

-     public interface User

  Represents an authenticates User and contains operations to authorise the user.

  Please consult the documentation for a detailed explanation.

  Author:
    Tim Fox

- - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Default Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `JsonObject` | `attributes()` | Gets extra attributes of the user.
    `default Authorizations` | `authorizations()` | Returns user's authorizations that have been previously loaded by the providers.
    `default boolean` | `containsKey​(String key)` | Checks if a value exists on the user object.
    `static User` | `create​(JsonObject principal)` | Factory for user instances that are free form.
    `static User` | `create​(JsonObject principal, JsonObject attributes)` | Factory for user instances that are free form.
    `default boolean` | `expired()` | Flags this user object to be expired.
    `default boolean` | `expired​(int leeway)` | Flags this user object to be expired.
    `static User` | `fromName​(String username)` | Factory for user instances that are single string.
    `static User` | `fromToken​(String token)` | Factory for user instances that are single string.
    `default <T> T` | `get​(String key)` | Get a value from the user object.
    `default <T> T` | `getOrDefault​(String key, T defaultValue)` | Get a value from the user object.
    `default boolean` | `hasAmr​(String value)` | The "amr" (Authentication Methods References) returns a unique list of claims as defined and registered in the IANA "JSON Web Token Claims" registry.
    `User` | `merge​(User other)` | Merge the principal and attributes of a second user into this object properties.
    `JsonObject` | `principal()` | Get the underlying principal for the User.
    `default String` | `subject()` | The user subject.

- - ### Method Detail

    - #### fromName

          static User fromName​(String username)

      Factory for user instances that are single string. The credentials will be added to the principal of this instance. As nothing can be said about the credentials no validation will be done.

      Will create a principal with a property `"username"` with the name as value.

      Parameters:
        `username` - the value for this user
      Returns:
        user instance

    - #### fromToken

          static User fromToken​(String token)

      Factory for user instances that are single string. The credentials will be added to the principal of this instance. As nothing can be said about the credentials no validation will be done.

      Will create a principal with a property `"access_token"` with the name as value.

      Parameters:
        `token` - the value for this user
      Returns:
        user instance

    - #### create

          static User create​(JsonObject principal)

      Factory for user instances that are free form. The credentials will be added to the principal of this instance. As nothing can be said about the credentials no validation will be done.
      Parameters:
        `principal` - the free form json principal
      Returns:
        user instance

    - #### create

          static User create​(JsonObject principal,
                             JsonObject attributes)

      Factory for user instances that are free form. The credentials will be added to the principal of this instance. As nothing can be said about the credentials no validation will be done.
      Parameters:
        `principal` - the free form json principal
        `attributes` - the free form json attributes that further describe the principal
      Returns:
        user instance

    - #### subject

          default String subject()

      The user subject. Usually a human representation that identifies this user.

      The lookup for this information will take place in several places in the following order:

      1. `principal.username` - Usually for username/password or webauthn authentication
      2. `principal.userHandle` - Optional field for webauthn
      3. `attributes.idToken.sub` - For OpenID Connect ID Tokens
      4. `attributes.[rootClaim?]accessToken.sub` - For OpenID Connect/OAuth2 Access Tokens
      Returns:
        the subject for this user or `null`.

    - #### attributes

          JsonObject attributes()

      Gets extra attributes of the user. Attributes contain any attributes related to the outcome of authenticating a user (e.g.: issued date, metadata, etc...)
      Returns:
        a json object with any relevant attribute.

    - #### expired

          default boolean expired()

      Flags this user object to be expired. A User is considered expired if it contains an expiration time and the current clock time is post the expiration date.
      Returns:
        `true` if expired

    - #### expired

          default boolean expired​(int leeway)

      Flags this user object to be expired. Expiration takes 3 values in account:
      1. `exp` "expiration" timestamp in seconds.
      2. `iat` "issued at" in seconds.
      3. `nbf` "not before" in seconds.
      A User is considered expired if it contains any of the above and the current clock time does not agree with the parameter value. If the `attributes()` do not contain a key then `principal()` properties are checked.

      If all of the properties are not available the user will not expire.

      Implementations of this interface might relax this rule to account for a leeway to safeguard against clock drifting.

      Parameters:
        `leeway` - a greater than zero leeway value.
      Returns:
        `true` if expired

    - #### get

          default <T> T get​(String key)

      Get a value from the user object. This method will perform lookups on several places before returning a value.
      1. If there is a `rootClaim` the look up will happen in the `attributes[rootClaim]`
      2. If exists the value will be returned from the `attributes()`
      3. If exists the value will be returned from the `principal()`
      4. Otherwise it will be `null`
      Type Parameters:
        `T` - the expected type
      Parameters:
        `key` - the key to look up
      Returns:
        the value or null if missing
      Throws:
        `ClassCastException` - if the value cannot be casted to `T`

    - #### getOrDefault

          default <T> T getOrDefault​(String key,
                                     T defaultValue)

      Get a value from the user object. This method will perform lookups on several places before returning a value.
      1. If there is a `rootClaim` the look up will happen in the `attributes[rootClaim]`
      2. If exists the value will be returned from the `attributes()`
      3. If exists the value will be returned from the `principal()`
      4. Otherwise it will be `null`
      Type Parameters:
        `T` - the expected type
      Parameters:
        `key` - the key to look up
        `defaultValue` - default value to return if missing
      Returns:
        the value or null if missing
      Throws:
        `ClassCastException` - if the value cannot be casted to `T`

    - #### containsKey

          default boolean containsKey​(String key)

      Checks if a value exists on the user object. This method will perform lookups on several places before returning.
      1. If there is a `rootClaim` the look up will happen in the `attributes[rootClaim]`
      2. If exists the value will be returned from the `attributes()`
      3. If exists the value will be returned from the `principal()`
      4. Otherwise it will be `null`
      Parameters:
        `key` - the key to look up
      Returns:
        the value or null if missing

    - #### authorizations

          default Authorizations authorizations()

      Returns user's authorizations that have been previously loaded by the providers.
      Returns:
        authorizations holder for the user.

    - #### principal

          JsonObject principal()

      Get the underlying principal for the User. What this actually returns depends on the implementation. For a simple user/password based auth, it's likely to contain a JSON object with the following structure:

             {
               "username", "tim"
             }

      Returns:
        JSON representation of the Principal

    - #### merge

          User merge​(User other)

      Merge the principal and attributes of a second user into this object properties.

      It is important to notice that the principal merges by replacing existing keys with the new values, while the attributes (as they represent decoded data) are accumulated at the root level.

      This means that given:

           userA = {
             attributes: {
               roles: [ 'read' ]
             }
           }

           userB = {
             attributes: {
               roles: [ 'write' ]
             }
           }

      When performing a merge of `userA` with `userB`, you will get:

           userA.merge(userB);
           // results in
           {
             attributes: {
               roles: [ 'read', 'write' ]
             }
           }

      Parameters:
        `other` - the other user to merge
      Returns:
        fluent self

    - #### hasAmr

          default boolean hasAmr​(String value)

      The "amr" (Authentication Methods References) returns a unique list of claims as defined and registered in the IANA "JSON Web Token Claims" registry. The values in this collection are based on RFC8176. This information can be used to filter authenticated users by their authentication mechanism.
      Returns:
        `true` if claim is present in the principal.