Multi-provider authentication framework.
- Includes the following base strategies:
- OAuth 1.0 -
Assent.Strategy.OAuth
- OAuth 2.0 -
Assent.Strategy.OAuth2
- OpenID Connect -
Assent.Strategy.OIDC
- OAuth 1.0 -
- Includes the following provider strategies:
- Apple Sign In -
Assent.Strategy.Apple
- Auth0 -
Assent.Strategy.Auth0
- Azure AD -
Assent.Strategy.AzureAD
- Basecamp -
Assent.Strategy.Basecamp
- DigitalOcean -
Assent.Strategy.DigitalOcean
- Discord -
Assent.Strategy.Discord
- Facebook -
Assent.Strategy.Facebook
- Github -
Assent.Strategy.Github
- Gitlab -
Assent.Strategy.Gitlab
- Google -
Assent.Strategy.Google
- Instagram -
Assent.Strategy.Instagram
- LINE Login -
Assent.Strategy.LINE
- Linkedin -
Assent.Strategy.Linkedin
- Spotify -
Assent.Strategy.Spotify
- Strava -
Assent.Strategy.Strava
- Slack -
Assent.Strategy.Slack
- Stripe Connect -
Assent.Strategy.Stripe
- Twitter -
Assent.Strategy.Twitter
- VK -
Assent.Strategy.VK
- Apple Sign In -
Add Assent to your list of dependencies in mix.exs
:
defp deps do
[
# ...
{:assent, "~> 0.2.9"}
]
end
Run mix deps.get
to install it.
By default, Req
is used if you have it in your dependency list. If not, Erlang's :httpc
will be used instead.
If you are using :httpc
you should add the following dependencies to enable SSL validation:
defp deps do
[
# ...
# Required for SSL validation when using the `:httpc` adapter
{:certifi, "~> 2.4"},
{:ssl_verify_fun, "~> 1.1"}
]
end
You must also add :inets
to :extra_applications
in mix.exs
:
def application do
[
# ...
extra_applications: [
# ...
:inets
]
]
end
This is not necessary if you use another HTTP adapter like Req
or Finch
.
A strategy consists of two phases; request and callback. In the request phase, the user would normally be redirected to the provider for authentication and then returned to initiate the callback phase.
defmodule ProviderAuth do
import Plug.Conn
alias Assent.{Config, Strategy.Github}
@config [
client_id: "REPLACE_WITH_CLIENT_ID",
client_secret: "REPLACE_WITH_CLIENT_SECRET",
redirect_uri: "https://localhost:4000/auth/github/callback"
]
# https://localhost:4000/auth/github
def request(conn) do
@config
|> Github.authorize_url()
|> case do
{:ok, %{url: url, session_params: session_params}} ->
# Session params (used for OAuth 2.0 and OIDC strategies) will be
# retrieved when user returns for the callback phase
conn = put_session(conn, :session_params, session_params)
# Redirect end-user to Github to authorize access to their account
conn
|> put_resp_header("location", url)
|> send_resp(302, "")
{:error, error} ->
# Something went wrong generating the request authorization url
end
end
# https://localhost:4000/auth/github/callback
def callback(conn) do
# End-user will return to the callback URL with params attached to the
# request. These must be passed on to the strategy. In this example we only
# expect GET query params, but the provider could also return the user with
# a POST request where the params is in the POST body.
%{params: params} = fetch_query_params(conn)
# The session params (used for OAuth 2.0 and OIDC strategies) stored in the
# request phase will be used in the callback phase
session_params = get_session(conn, :session_params)
@config
# Session params should be added to the config so the strategy can use them
|> Config.put(:session_params, session_params)
|> Github.callback(params)
|> case do
{:ok, %{user: user, token: token}} ->
# Authorization succesful
{:error, error} ->
# Authorizaiton failed
end
end
end
This is a generalized flow that's similar to what's used in PowAssent.
config :my_app, :strategies,
github: [
client_id: "REPLACE_WITH_CLIENT_ID",
client_secret: "REPLACE_WITH_CLIENT_SECRET",
strategy: Assent.Strategy.Github
],
# ...
defmodule MultiProviderAuth do
alias Assent.Config
@spec request(atom()) :: {:ok, map()} | {:error, term()}
def request(provider) do
config = config!(provider)
config[:strategy].authorize_url()
end
@spec callback(atom(), map(), map()) :: {:ok, map()} | {:error, term()}
def callback(provider, params, session_params) do
config = config!(provider)
config
|> Assent.Config.put(:session_params, session_params)
|> config[:strategy].callback(params)
end
defp config!(provider) do
config =
Application.get_env(:my_app, :strategies)[provider] ||
raise "No provider configuration for #{provider}"
Config.put(config, :redirect_uri, "https://localhost:4000/oauth/#{provider}/callback")
end
end
You can create custom strategies. Here's an example of an OAuth 2.0 implementation using Assent.Strategy.OAuth2.Base
:
defmodule TestProvider do
use Assent.Strategy.OAuth2.Base
@impl true
def default_config(_config) do
[
# `:base_url` will be used for any paths below
base_url: "https://localhost:4000/api/v1",
# Definining an absolute URI overrides the `:base_url`
authorize_url: "https://localhost:4000/oauth/authorize",
token_url: "/oauth/access_token",
user_url: "/user",
authorization_params: [scope: "email profile"],
auth_method: :client_secret_post
]
end
@impl true
def normalize(_config, user) do
{:ok,
# Conformed to https://openid.net/specs/openid-connect-core-1_0.html#rfc.section.5.1
%{
"sub" => user["sub"],
"name" => user["name"],
"nickname" => user["username"],
"email" => user["email"]
# },
# # Provider specific data not part of the standard claims spec
# %{
# "https://localhost:4000/bio" => user["bio"]
}
}
end
end
The normalized user map should conform to the OpenID Connect Core 1.0 Standard Claims spec, and should return either {:ok, userinfo_claims}
or {:ok, userinfo_claims, additional}
. Any keys defined in the userinfo claims that aren't part of the specs will not be included in the user map. Instead, they should be set in the additional data that will then be merged on top of the userinfo claims excluding any keys that have already been set.
You can use any of the Assent.Strategy.OAuth2.Base
, Assent.Strategy.OAuth.Base
, and Assent.Strategy.OIDC.Base
macros to set up the strategy.
If you need more control over the strategy than what the macros give you, you can implement your provider using the Assent.Strategy
behaviour:
defmodule TestProvider do
@behaviour Assent.Strategy
@spec authorize_url(Keyword.t()) :: {:ok, %{url: binary()}} | {:error, term()}
def authorize_url(config) do
# Generate authorization url
end
@spec callback(Keyword.t(), map()) :: {:ok, %{user: map(), token: map()}} | {:error, term()}
def callback(config, params) do
# Handle callback response
end
end
Assent supports Req
, Finch
, and :httpc
out of the box. The Req
HTTP client adapter will be used by default if enabled, otherwise Erlang's :httpc
adapter will be included.
You can explicitly set the HTTP client adapter in the configuration:
config = [
client_id: "REPLACE_WITH_CLIENT_ID",
client_secret: "REPLACE_WITH_CLIENT_SECRET",
http_adapter: Assent.HTTPAdapter.Httpc
]
Or globally in the config:
config :assent, http_adapter: Assent.HTTPAdapter.Httpc
Req doesn't require any additional configuration and will work out of the box:
defp deps do
[
# ...
{:req, "~> 0.4"}
]
end
If Req
is not available, Erlangs built-in :httpc
is used for requests. SSL verification is automatically enabled when :certifi
and :ssl_verify_fun
packages are available. :httpc
only supports HTTP/1.1.
defp deps do
[
# ...
# Required for SSL validation if using the `:httpc` adapter
{:certifi, "~> 2.4"},
{:ssl_verify_fun, "~> 1.1"}
]
end
You must include :inets
to :extra_applications
to include :httpc
in your release.
Finch will require a supervisor in your application.
Update mix.exs
:
defp deps do
[
# ...
{:finch, "~> 0.16"}
]
end
Ensure you start the Finch supervisor in your application, and set :http_adapter
in your provider configuration using your connection pool:
config = [
client_id: "REPLACE_WITH_CLIENT_ID",
client_secret: "REPLACE_WITH_CLIENT_SECRET",
http_adapter: {Assent.HTTPAdapter.Finch, supervisor: MyFinch}
]
By default the built-in Assent.JWTAdapter.AssentJWT
is used for JWT parsing, but you can change it to any third-party library with a custom Assent.JWTAdapter
. A JOSE adapter Assent.JWTAdapter.JOSE
is included.
To use JOSE, update mix.exs
:
defp deps do
[
# ...
{:jose, "~> 1.8"}
]
end
And pass the :jwt_adapter
with your provider configuration:
config = [
client_id: "REPLACE_WITH_CLIENT_ID",
client_secret: "REPLACE_WITH_CLIENT_SECRET",
jwt_adapter: Assent.JWTAdapter.JOSE
]
Or globally in the config:
config :assent, jwt_adapter: AssAssent.JWTAdapter.JOSE
(The MIT License)
Copyright (c) 2019-present Dan Schultzer & the Contributors
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.