Add OAuth log in via new log_in_oauth method (#42)

Author: 4DA

README.md

@@ -68,6 +68,14 @@ iex> conn = Hunter.log_in(app, "[email protected]", "your_password", "https://exa
  bearer_token: "123456"}
 ```
 
+Or, if you want to use [OAuth code](https://docs.joinmastodon.org/methods/apps/oauth/) for authentication:
+
+```elixir
+iex> conn = Hunter.log_in_oauth(app, "123456code", "https://example.com")
+%Hunter.Client{base_url: "https://example.com",
+ bearer_token: "123456"}
+```
+
 Now you can use `conn` in any API request.
 
 If you don't want to register an application but you already know your

lib/hunter/api.ex

@@ -681,6 +681,22 @@ defmodule Hunter.Api do
               base_url :: String.t()
             ) :: Hunter.Client.t()
 
+  @doc """
+  Retrieve access token using OAuth access code
+
+  ## Parameters
+
+    * `app` - application details, see: `Hunter.Application.create_app/5` for more details.
+    * `oauth_code` - oauth authentication code
+    * `base_url` - API base url, default: `https://mastodon.social`
+
+  """
+  @callback log_in_oauth(
+              app :: Hunter.Application.t(),
+              oauth_code :: String.t(),
+              base_url :: String.t()
+            ) :: Hunter.Client.t()
+
   @doc """
   Fetch user's blocked domains
 

lib/hunter/api/http_client.ex

@@ -319,6 +319,26 @@ defmodule Hunter.Api.HTTPClient do
     %Hunter.Client{base_url: base_url, bearer_token: response["access_token"]}
   end
 
+  def log_in_oauth(
+        %Hunter.Application{client_id: client_id, client_secret: client_secret},
+        oauth_code,
+        base_url
+      ) do
+    payload = %{
+      client_id: client_id,
+      client_secret: client_secret,
+      grant_type: "authorization_code",
+      code: oauth_code
+    }
+
+    response =
+      "/oauth/token"
+      |> process_url(base_url)
+      |> request!(nil, :post, payload)
+
+    %Hunter.Client{base_url: base_url, bearer_token: response["access_token"]}
+  end
+
   def blocked_domains(conn, options) do
     "/api/v1/domain_blocks"
     |> process_url(conn)

lib/hunter/client.ex

@@ -51,4 +51,21 @@ defmodule Hunter.Client do
     base_url = base_url || Config.api_base_url()
     Config.hunter_api().log_in(app, username, password, base_url)
   end
+
+  @doc """
+  Retrieve access token
+
+  ## Parameters
+
+    * `app` - application details, see: `Hunter.Application.create_app/5` for more details.
+    * `oauth_code` - oauth authentication code
+    * `base_url` - API base url, default: `https://mastodon.social`
+
+  """
+  @spec log_in_oauth(Hunter.Application.t(), String.t(), String.t()) :: Hunter.Client.t()
+  def log_in_oauth(app, oauth_code, base_url \\ "https://mastodon.social") do
+    base_url = base_url || Config.api_base_url()
+    Config.hunter_api().log_in_oauth(app, oauth_code, base_url)
+  end
+
 end