Coherence

Alert: Project under active development!

This is an early release. So expect changes and new features in the near future.

Checkout the Coherence Demo Project to see an example project using Coherence.

Coherence is a full featured, configurable authentication system for Phoenix, with the following modules:

• Database Authenticatable: handles hashing and storing an encrypted password in the database.
• Invitable: sends invites to new users with a sign-up link, allowing the user to create their account with their own password.
• Registerable: allows anonymous users to register a users email address and password.
• Confirmable: new accounts require clicking a link in a confirmation email.
• Recoverable: provides a link to generate a password reset link with token expiry.
• Trackable: saves login statistics like login counts, timestamps, and IP address for each user.
• Lockable: locks an account when a specified number of failed sign-in attempts has been exceeded.
• Unlockable With Token: provides a link to send yourself an unlock email.
• Rememberable: provides persistent login with 'Remember me?' check box on login page.

Coherence provides flexibility by adding namespaced templates and views for only the options specified by the mix coherence.install command. This boiler plate code is added to your web/templates/coherence and web/views/coherence directories.

Once the boilerplate has been generated, you are free to customize the source as required.

As well, a web/coherence_web.ex is added. Migrations are also generated to add the required database fields.

See the Docs and Wiki for more information.

Installation

1. Add coherence to your list of dependencies in mix.exs:

def deps do
  [{:coherence, "~> 0.3"}]
end

2. Ensure coherence is started before your application:

def application do
  [applications: [:coherence]]
end

Upgrading

After upgrading a Coherence version, you should generate the boilerplate files. To assist this process, use the --reinstall option.

This option uses your project's existing coherence config and runs the the installer with the same options.

mix coherence.install --reinstall

Run a git diff to review the updated files. If you had updated any of the boilerplate files, you may need to manually integrate the changes into the newly generated files.

Run mix help coherence.install for more information.

Getting Started

First, decide with modules you would like to use for your project. For the following example were are going to use a full install except for the confirmable option.

Run the installer

$ mix coherence.install --full-invitable

This will:

• add the coherence configuration to the end of your config/config.exs file.
• add a new User model if one does not already exist
• add migration files
  • timestamp_add_coherence_to_user.exs if the User model already exists
  • timestamp_create_coherence_user.exs if the User model does not exist
  • timestamp_create_coherence_invitable.exs
• add view files web/views/coherence/
• add template files to web/templates/coherence
• add email files to web/emails/coherence
• add web/coherence_web.ex file

You should review your config/config.exs as there are a couple items you will need to customize like email address and mail api_key. If you don't edit the email_from value to something different than it's default emails may not be sent.

See Installer for more install options.

You will need to update a few files manually.

# web/router.ex

defmodule MyProject.Router do
  use MyProject.Web, :router
  use Coherence.Router         # Add this

  pipeline :browser do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_flash
    plug :protect_from_forgery
    plug :put_secure_browser_headers
    plug Coherence.Authentication.Session  # Add this
  end

  pipeline :protected do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_flash
    plug :protect_from_forgery
    plug :put_secure_browser_headers
    plug Coherence.Authentication.Session, protected: true
  end

  # Add this block
  scope "/" do
    pipe_through :browser
    coherence_routes()
  end

  # Add this block
  scope "/" do
    pipe_through :protected
    coherence_routes :protected
  end

  scope "/", MyProject do
    pipe_through :browser

    get "/", PageController, :index
    # add public resources below
  end

  scope "/", MyProject do
    pipe_through :protected

    # add protected resources below
    resources "/privates", MyProject.PrivateController
  end
end

Important: Note the name-spacing above. Unless you generate coherence controllers, ensure that the scopes, scope "/" do, do not include your projects' scope here. If so, the coherence routes will not work!

If the installer created a user model (one did not already exist), there is nothing you need to do with that generated file. Otherwise, update your existing model like this:

# web/models/user.ex

defmodule MyProject.User do
  use MyProject.Web, :model
  use Coherence.Schema                                    # Add this

  schema "users" do
    field :name, :string
    field :email, :string
    coherence_schema                                      # Add this

    timestamps
  end

  def changeset(model, params \\ %{}) do
    model
    |> cast(params, [:name, :email] ++ coherence_fields)  # Add this
    |> validate_required([:name, :email])
    |> validate_format(:email, ~r/@/)
    |> validate_coherence(params)                         # Add this
  end

  def changeset(model, params, :password) do
    model
    |> cast(params, ~w(password password_confirmation reset_password_token reset_password_sent_at))
    |> validate_coherence_password_reset(params)
  end
end

An alternative approach is add the authentication plugs to individual controllers that require authentication. You will want to use this approach if you require authentication for a subset of actions in a controller.

For example, lets say you want to show a list of products for everyone visiting the site, but only want authenticated users to be able to create, update, and delete products. You could do the following:

Ensure the following is in your web/router.ex file:

  scope "/", MyProject do
    pipe_through :browser
    resources "/products", ProductController
  end

In your product controller add the following:

defmodule MyProject.ProductController do
  use MyProject.Web, :controller

  plug Coherence.Authentication.Session, [protected: true] when action != :index

  # ...

Default Configuration

{:require_current_password, true}, # Current password is required when updating new password.
{:reset_token_expire_days, 2},
{:confirmation_token_expire_days, 5},
{:allow_unconfirmed_access_for, 0},
{:max_failed_login_attempts, 5},
{:unlock_timeout_minutes, 20},
{:unlock_token_expire_minutes, 5},
{:rememberable_cookie_expire_hours, 2*24}

You can override this default configs. For example: you can add the following codes inside config/config.exs

config :coherence,
  require_current_password: false,
  max_failed_login_attempts: 3

Phoenix Channel Authentication

Coherence supports channel authentication using Phoenix.Token. To enable channel authentication do the following:

Add the following option to coherence configuration.

config :coherence,
  user_token: true,

Update your socket module

defmodule MyProject.UserSocket do
  use Phoenix.Socket
  def connect(%{"token" => token}, socket) do
    case Coherence.verify_user_token(socket, token, &assign/3) do
      {:error, _} -> :error
      {:ok, socket} -> {:ok, socket}
    end
  end

Option Overview

Authenticatable

Handles hashing and storing an encrypted password in the database.

Provides /sessions/new and /sessions/delete routes for logging in and out with the appropriate templates and view.

The following columns are added the <timestamp>_add_coherence_to_user.exs migration:

• :password_hash, :string - the encrypted password

Invitable

Handles sending invites to new users with a sign-up link, allowing the user to create their account with their own password.

Provides /invitations/new and invitations/edit routes for creating a new invitation and creating a new account from the invite email.

These routes can be configured to require login by using the coherence_routes :private macro in your router.exs file.

Invitation token timeout will be added in the future.

The following table is created by the generated <timestamp>_create_coherence_invitable.exs migration:

create table(:invitations) do
  add :name, :string
  add :email, :string
  add :token, :string
end

Registerable

Allows anonymous users to register a users email address and password.

Provides /registrations/new, create, edit, update, show, and delete routes for managing registrations.

Adds the following:

• Register New Account to the log-in page.
• Link to account page on layout helpers
• Show page with edit and delete links
• edit page

It is recommended that the :confirmable option is used with :registerable to ensure a valid email address is captured.

Confirmable

Requires a new account be confirmed. During registration, a confirmation token is generated and sent to the registering email. This link must be clicked before the user can sign-in.

Provides edit action for the /confirmations route.

The confirmation token expiry default of 5 days can be changed with the :confirmation_token_expire_days config entry.

Recoverable

Allows users to reset their password using an expiring token send by email.

Provides new, create, edit, update actions for the /passwords route.

Adds a "Forgot your password?" link to the log-in form. When clicked, the user provides their email address and if found, sends a reset password instructions email with a reset link.

The expiry timeout can be changed with the :reset_token_expire_days config entry.

Trackable

Saves login statistics like login counts, timestamps, and IP address for each user.

Adds the following database field to your User model with the generated migration:

add :sign_in_count, :integer, default: 0  # how many times the user has logged in
add :current_sign_in_at, :datetime        # the current login timestamp
add :last_sign_in_at, :datetime           # the timestamp of the previous login
add :current_sign_in_ip, :string          # the current login IP adddress
add :last_sign_in_ip, :string             # the IP address of the previous login

Lockable

Locks an account when a specified number of failed sign-in attempts has been exceeded.

The following defaults can be changed with the following config entries:

• :unlock_timeout_minutes
• :max_failed_login_attempts

Adds the following database field to your User model with the generated migration:

add :failed_attempts, :integer, default: 0
add :unlock_token, :string
add :locked_at, :datetime

Unlockable with Token

Provides a link to send yourself an unlock email. When the user clicks the link, the user is presented a form to enter their email address and password. If the token has not expired and the email and password are valid, a unlock email is sent to the user's email address with an expiring token.

The default expiry time can be changed with the :unlock_token_expire_minutes config entry.

Remember Me

The rememberable option provides persistent login when the 'Remember Me?' box is checked during login.

With this feature, you will automatically be logged in from the same browser when your current login session dies using a configurable expiring persistent cookie.

For security, both a token and series number stored in the cookie on initial login. Each new creates a new token, but preserves the series number, providing protection against fraud. As well, both the token and series numbers are hashed before saving them to the database, providing protection if the database is compromised.

The following defaults can be changed with the following config entries:

• :rememberable_cookie_expire_hours (2*24)
• :login_cookie ("coherence_login")

The following table is created by the generated <timestamp>_create_coherence_rememberable.exs migration:

create table(:rememberables) do
  add :series_hash, :string
  add :token_hash, :string
  add :token_created_at, :datetime
  add :user_id, references(:users, on_delete: :delete_all)

  timestamps
end
create index(:rememberables, [:user_id])
create index(:rememberables, [:series_hash])
create index(:rememberables, [:token_hash])
create unique_index(:rememberables, [:user_id, :series_hash, :token_hash])

The --rememberable install option is not provided in any of the installer group options. You must provide the --rememberable option to install the migration and its support.

Mix Tasks

Installer

The following examples illustrate various configuration scenarios for the install mix task:

  # Install with only the `authenticatable` option
  $ mix coherence.install

  # Install all the options except `confirmable` and `invitable`
  $ mix coherence.install --full

  # Install all the options except `invitable`
  $ mix coherence.install --full-confirmable

  # Install all the options except `confirmable`
  $ mix coherence.install --full-invitable

  # Install the `full` options except `lockable` and `trackable`
  $ mix coherence.install --full --no-lockable --no-trackable

And some reinstall examples:

  # Reinstall with defaults (--silent --no-migrations --no-config --confirm-once)
  $ mix coherence.install --reinstall

  # Confirm to overwrite files, show instructions, and generate migrations
  $ mix coherence.install --reinstall --no-confirm-once --with-migrations

Run $ mix help coherence.install for more information.

Clean

The following examples illustrate how to remove the files created by the installer:

  # Clean all the installed files
  $ mix coherence.clean --all

  # Clean only the installed view and template files
  $ mix coherence.clean --views --templates

  # Clean all but the models
  $ mix coherence.clean --all --no-models

  # Prompt once to confirm the removal
  $ mix coherence.clean --all --confirm-once

After installation, if you later want to remove one more options, here are a couple examples:

  # Clean one option
  $ mix coherence.clean --options=recoverable

  # Clean several options without confirmation
  $ mix coherence.clean --no-confirm --options="recoverable unlockable-with-token"

  # Test the uninstaller without removing files
  $ mix coherence.clean --dry-run --options="recoverable unlockable-with-token"

Customization

The coherence.install mix task generates a bunch of boiler plate code so you can easily customize the views, templates, and mailer.

Also, checkout the Coherence.Config module for a list of config items you can use to tune the behaviour of Coherence.

Custom Controllers

By default, controller boilerplate is not generated unless the --controllers option is provided to mix coherence.install.

The generated controllers are named MyProject.Coherence.SessionController as an example. Generated controllers are located in web/controllers/coherence/

If the controllers are generated, you will need to change your router to use the new names. For example:

  # web/router.ex
  use MyProject.Web, :router
  use Coherence.Router

  # ...

  scope "/", MyProject do   # note the addition of MyProject
    pipe_through :public
    coherence_routes :public
  end

  scope "/", MyProject do   # note the addition of MyProject
    pipe_through :browser
    coherence_routes :private
  end
  # ...
end

Customizing Routes

By default, Coherence assumes you want all available routes for the opts you've configured. However, you can specify which routes should be available by modifying your configuration.

For example, if you want all of the routes for authenticatable, but only the new and create actions from registerable:

# config/config.exs
config :coherence,
  # ...
  opts: [:authenticatable, registerable: [:new, :create]]

Customizing Redirections

Many of the controller actions redirect the user after create and update actions. These redirections can be customized by adding function call backs in the web/controllers/redirect.ex module that is generated by the mix coherence.install task.

For example, to have the user redirected to the login screen after logging out at the following:

defmodule Coherence.Redirects do
  use Redirects
  import MyProject.Router.Helpers

  # override the log out action back to the log in page
  def session_delete(conn, _), do: redirect(conn, session_path(conn, :new))
end

See the documentation for further details.

Customizing layout

By default coherence uses its own layout, that is installed to web/templates/coherence/layout/app.html.eex.

If you want to customize coherence controllers layout, you can follow different approaches:

• Edit the generated layout at web/templates/coherence/layout/app.html.eex.
• Set :layout in your config file. e.g. config :coherence, :layout, {MyProject.LayoutView, :app}
• Install coherence controllers to application and edit them, to use layout module different from Coherence.LayoutView
• And the last solution is to use plug :put_layout in your web/router.ex file. For example:

defmodule MyApp.Router do
  # ...
  pipeline :coherence do
    plug :put_layout, {MyProject.LayoutView, :app}
  end
  # ...
  scope "/" do
    pipe_through [:protected, :coherence]
    coherence_routes :protected
  end
  #...
end

Customizing User Changeset

The User model changeset used by Coherence can be customized for each Coherence controller. To customize the changeset, set the changeset config option.

For example, the following defines a changeset/3 function in your user model:

  # config/config.exs
  config :coherence,
    # ...
    changeset: {MyProject.User, :changeset}

Now add a new changeset/3 function to the user model. The following example defines a custom changeset for the registration controller:

  # web/models/coherence/user.ex
  defmodule CoherenceDemo.User do
    use CoherenceDemo.Web, :model
    use Coherence.Schema

    # ...

    def changeset(model, params \\ %{}) do
      model
      |> cast(params, [:name, :email] ++ coherence_fields)
      |> validate_required([:name, :email])
      |> validate_format(:email, ~r/@/)
      |> unique_constraint(:email)
      |> validate_coherence(params)
    end
    def changeset(model, params, :registration) do
      # custom changeset  for registration controller
      model
      |> cast(params, [:name, :email] ++ coherence_fields)
      |> validate_required([:name, :email])
      |> validate_format(:email, ~r/@/)
      |> unique_constraint(:email)
      |> validate_coherence(params)
    end
    def changeset(model, params, _which) do
      # use the default changeset for all other coherence controllers
      changeset model, params
    end
  end

When a custom changeset is configured, the changeset function is called with an atom indicating the controller calling the changeset, allowing you to match on specific controllers.

The list of controller actions are:

• :confirmation
• :invitation
• :password
• :registration
• :session
• :unlock

Accessing the Currently Logged In User

During login, a current version of the user model is cashed in the credential store. During each authentication request, the user model is fetched from the credential store and placed in conn.assigns[:current_user] to avoid a database fetch on each request.

You can access the current user's name in a template like this:

<%= @current_user.name %/>

Any of the user model's available data can be accessed this way.

Updating the User Model

If the user model is changed after login, a call to update_login must be done to update the credential store. For example, in your controller update function, call:

apply(Config.auth_module, Config.update_login, [conn, user, [id_key: Config.schema_key]])

to update the credential store.

This is not needed for registration update page.

Configuring the Swoosh Email Adapter

The following configuration must be setup to send emails:

config :coherence,
  email_from_name: "Some Name",
  email_from_email: "[email protected]"

config :coherence, CoherenceDemo.Coherence.Mailer,
  adapter: Swoosh.Adapters.Sendgrid,
  api_key: "Add api key here"

You may want to configure the email system to use system environment variables.

config :coherence,
  email_from_name: {:system, "NAME"},
  email_from_email: {:system, "EMAIL"}

config :coherence, CoherenceDemo.Coherence.Mailer,
  api_key: {:system, "API_KEY"}

Authentication

Currently Coherence supports three modes of authentication including HTTP Basic, Session, and Token authentication.

For HTTP Basic and Token authentication, you will need to add the credentials into the Credential Store. This is not required for Session or IpAddress Authentication.

IpAddress authentication is a good solution for server to server rest APIs.

Add HTTP Basic Credentials Example

creds = Coherence.Authentication.Basic.encode_credentials("Admin", "SecretPass")
Coherence.CredentialStore.Agent.put_credentials(creds, %{role: :admin})

Add Token Credentials Example

token = Coherence.Authentication.Token.generate_token
Coherence.CredentialStore.Agent.put_credentials(token, %{role: :admin})

Add IP Credentials Example

Coherence.CredentialStore.Agent.put_credentials({127.0.0.1}, %{role: :admin})

IpAddress authentication does not require this step. Its optional. If the user_data is not found in the credential store, the conn.assigns will not be set.

To add authentication, use on of the following three:

HTTP Basic Plug Example

plug Coherence.Authentication.Basic, realm: "Secret"

The realm parameter is optional and can be omitted. By default "Restricted Area" will be used as realm name. You can also pass the error parameter, which should be a string or a function. If a string is passed, that string will be sent instead of the default message "HTTP Authentication Required" on authentication failure (with status code 401). If a function is passed, that function will be called with one argument, conn.

Token Plug Example

plug Coherence.Authentication.Token, source: :params, param: "auth_token", error: ~s'{"error":"authentication required"}'

The error parameter is optional and is treated as in the example above. The source parameter defines how to retrieve the token from the connection. Currently, the three acceptable values are: :params, :header and :session. Their name is self-explainatory. The param parameter defines the name of the parameter/HTTP header/session key where the token is stored. This should cover most cases, but if retrieving the token is more complex than that, you can pass a tuple for the source parameter. The tuple must be in the form {MyModule, :my_function, ["param1", 42]}. The function must accept a connection as its first argument (which will be injected as the head of the given parameter list) and any other number of parameters, which must be given in the third element of the tuple. If no additional arguments are needed, an empty list must be given.

Session Plug Example

plug Coherence.Authentication.Session, cookie_expire: 10*60*60, login: &MyController.login/1, assigns_key: :authenticated_user

The :cookie_expire value the expire time in seconds. The :login is a fun that will be passed conn if the user is not logged in. Use the :assigns_key to change the default :current_user value.

Note that if you provide a login callback, that you must return halt conn a the end of the function.

IP Address Plug Example

plug Coherence.Authentication.IpAddress, allow: ~w(127.0.0.1 192.168.1.0/24)
plug Coherence.Authentication.IpAddress, allow: ~w(0.0.0.0/0), deny: ~w(127.0.0.1)

The first example will allow local host and any ip address in the subnet 192.168.1.0/255.255.255.0

The second example allows any ip except for localhost.

Authorization

Coherence is a user management and authentication solution. Support for authorization (access control) can be achieved using another package like Canary.

For an example of using Canary with Coherence, please visit the CoherenceDemo canary branch.

Contributing

We appreciate any contribution to Coherence. Check our CODE_OF_CONDUCT.md and CONTRIBUTING.md guides for more information. We usually keep a list of features and bugs in the issue tracker.

References

• Detailed Example Coherence Demo
• Docs

License

coherence is Copyright (c) 2016 E-MetroTel

The source is released under the MIT License.

Check LICENSE for more information.

Much of the authentication code was taken from PlugAuth, Copyright (c) 2014, Bitgamma OÜ [email protected]