## The Apache Shiro Auth provider implementation

This is an auth provider implementation that uses Apache Shiro.

To use this project, add the following dependency to the dependencies section of your build descriptor:

- Maven (in your `pom.xml`):

    <dependency>
      <groupId>io.vertx</groupId>
      <artifactId>vertx-auth-shiro</artifactId>
      <version>3.1.0</version>
    </dependency>

- Gradle (in your `build.gradle` file):

    compile io.vertx:vertx-auth-shiro:3.1.0

We provide out of the box support for properties and LDAP based auth using Shiro, and you can also plugin in any other Shiro Realm which expects username and password for credentials.

To create an instance of the provider you use `ShiroAuth`. You specify the type of Shiro auth provider that you want with `ShiroAuthRealmType`, and you specify the configuration in a JSON object.

Here’s an example of creating a Shiro auth provider by specifying the type:

    require 'vertx-auth-shiro/shiro_auth'

    config = {
      'properties_path' => "classpath:test-auth.properties"
    }

    provider = VertxAuthShiro::ShiroAuth.create(vertx, :PROPERTIES, config)

## Authentication

When authenticating using this implementation, it assumes `username` and `password` fields are present in the authentication info:

    authInfo = {
      'username' => "tim",
      'password' => "sausages"
    }

    authProvider.authenticate(authInfo) { |res_err,res|
      if (res_err == nil)
        user = res
      else
        # Failed!
      end
    }

## Authorisation - Permission-Role Model

Although Vert.x auth itself does not mandate any specific model of permissions (they are just opaque strings), this implementation uses a familiar user/role/permission model, where a user can have zero or more roles and a role can have zero or more permissions.

If validating if a user has a particular permission simply pass the permission into. `isAuthorised` as follows:

    user.is_authorised("newsletter:edit:13") { |res_err,res|
      if (res_err == nil)
        hasPermission = res
      else
        # Failed to
      end
    }

If validating that a user has a particular role then you should prefix the argument with the role prefix.

    user.is_authorised("role:manager") { |res_err,res|
      if (res_err == nil)
        hasRole = res
      else
        # Failed to
      end
    }

The default role prefix is `role:`. You can change this with `setRolePrefix`.

### The Shiro properties auth provider

This auth provider implementation uses Apache Shiro to get user/role/permission information from a properties file.

Note that roles are not available directly on the API due to the fact that vertx-auth tries to be as portable as possible. However one can run assertions on role by using the prefix `role:` or by specifying the prefered prefix with `setRolePrefix`.

The implementation will, by default, look for a file called `vertx-users.properties` on the classpath.

If you want to change this, you can use the `properties_path` configuration element to define how the properties file is found.

The default value is `classpath:vertx-users.properties`.

If the value is prefixed with `classpath:` then the classpath will be searched for a properties file of that name.

If the value is prefixed with `file:` then it specifies a file on the file system.

If the value is prefixed with `url:` then it specifies a URL from where to load the properties.

The properties file should have the following structure:

Each line should either contain the username, password and roles for a user or the permissions in a role.

For a user line it should be of the form:

    user.{username}={password},{roleName1},{roleName2},...,{roleNameN}

For a role line it should be of the form:

    role.{roleName}={permissionName1},{permissionName2},...,{permissionNameN}

Here’s an example:

    user.tim = mypassword,administrator,developer
    user.bob = hispassword,developer
    user.joe = anotherpassword,manager
    role.administrator=*
    role.manager=play_golf,say_buzzwords
    role.developer=do_actual_work

When describing roles a wildcard `*` can be used to indicate that the role has all permissions.

### The Shiro LDAP auth provider

The LDAP auth realm gets user/role/permission information from an LDAP server.

The following configuration properties are used to configure the LDAP realm:

`ldap-user-dn-template`

  this is used to determine the actual lookup to use when looking up a user with a particular id. An example is `uid={0},ou=users,dc=foo,dc=com` - the element `{0}` is substituted with the user id to create the actual lookup. This setting is mandatory.

`ldap_url`

  the url to the LDAP server. The url must start with `ldap://` and a port must be specified. An example is `ldap:://myldapserver.mycompany.com:10389`

`ldap-authentication-mechanism`

  TODO

`ldap-context-factory-class-name`

  TODO

`ldap-pooling-enabled`

  TODO

`ldap-referral`

  TODO

`ldap-system-username`

  TODO

`ldap-system-password`

  TODO

### Using another Shiro Realm

It’s also possible to create an auth provider instance using a pre-created Apache Shiro Realm object.

This is done as follows:

    require 'vertx-auth-shiro/shiro_auth'

    provider = VertxAuthShiro::ShiroAuth.create(vertx, realm)

The implementation currently assumes that user/password based authentication is used.