Database backend sessions with Ecto.

ecto_sessions helps you easily and securely manage database backed sessions in your Ecto project.

It might be used, for example to manage authorization via cookies or API keys. The medium you will use the sessions is up to the application implementation. Ex: session id to be used in a Cookie or X-Api-Token for a REST API.

Using database backed session, might be very helpful in some scenarios. It has quite a few benefits and drawbacks comparing to signed sessions, for example JWT or signed cookies. It might also be used in combination with them.

Advantages:

• Ability to query active sessions for a given user. Ex: list the devices where a user has a valid session or lit the active API keys for a given project.
• Full control of the validity: at any time your application will be able to control if a given session is valid, change their expiration and even revalidate expired tokens.
• Ability to store arbitrary data, without increasing the token size. Ex: Device/token name, permissions, metadata, etc.

Disadvantages:

• Depending on the design, you might be adding a database query on each request - just like traditional sessions; Note that you can use a separate database, and furthermore this code might also be adapted for different backends, like key-value stores.
• Clients and other services will not be able to inspect the contents of the token. This might be useful for example to predict if a token is expired before making a request. This might also be considered an advantage in scenarios you don't want to give any control to the client.

One design that allows you to have the benefits of stateless and stateful sessions combined, is to have short-lived signed tokens, and database backed sessions for long-lived refresh tokens.

This repository includes a full phoenix demo project inside the ./demo directory. There's a hosted live version available at ecto-sessions-demo.tofran.com, feel free to play with it and see how it works/what features it enables.

The package can be installed by adding ecto_sessions to your list of dependencies in mix.exs:

def deps do
  [
    {:ecto_sessions, "> 0.0.0"}
  ]
end

Then, in your ecto app create the following module:

defmodule MyApp.Sessions do
  use EctoSessions,
    repo: MyApp.Repo
end

Refer to EctoSessions module documentation for more details.