Initial support for tesla to replace hackney

There are a lot of http client and a lot of ways of handling
requests. Using tesla we can allow users to pick what http
client they want and what configurations they want.

README.md

@@ -18,7 +18,8 @@ An Elixir [OAuth](https://en.wikipedia.org/wiki/OAuth) 2.0 Client Library.
 defp deps do
   # Add the dependency
   [
-    {:oauth2, "~> 2.0"}
+    {:oauth2, "~> 2.0"},
+    {:hackney, "~> 2.0"} # depending on what tesla adapter you use
   ]
 end
 ```
@@ -47,6 +48,26 @@ end
 Please see the documentation for [OAuth2.Serializer](https://hexdocs.pm/oauth2/OAuth2.Serializer.html)
 for more details.
 
+## Configure a http client
+
+The http client library used is [tesla](https://github.com/elixir-tesla/tesla), the default adapter is
+Httpc, since it comes out of the box with every Erlang instance but you can easily change it to something
+better.
+You can configure another adaptor like this:
+
+```elixir
+config :oauth2, adapter: Tesla.Adapter.Mint
+```
+
+You can also add your own tesla middleware:
+
+```elixir
+config :oauth2, middleware: [
+  Tesla.Middleware.Retry,
+  {Tesla.Middleware.Fuse, name: :example}
+]
+```
+
 ## Debug mode
 
 Sometimes it's handy to see what's coming back from the response when getting

config/config.exs

@@ -8,4 +8,9 @@ config :oauth2,
   # second commit sha
   client_secret: "f715d64092fe81c396ac383e97f8a7eca40e7c89",
   redirect_uri: "http://example.com/auth/callback",
-  request_opts: []
+  request_opts: [],
+  middleware: []
+
+if Mix.env() == :test do
+  config :oauth2, adapter: Tesla.Adapter.Hackney
+end

lib/oauth2/request.ex

@@ -14,13 +14,14 @@ defmodule OAuth2.Request do
   @spec request(atom, Client.t(), binary, body, Client.headers(), Keyword.t()) ::
           {:ok, Response.t()} | {:ok, reference} | {:error, Response.t()} | {:error, Error.t()}
   def request(method, %Client{} = client, url, body, headers, opts) do
-    url = client |> process_url(url) |> process_params(opts[:params])
+    url = process_url(client, url)
     headers = req_headers(client, headers) |> normalize_headers() |> Enum.uniq()
     content_type = content_type(headers)
     serializer = Client.get_serializer(client, content_type)
     body = encode_request_body(body, content_type, serializer)
     headers = process_request_headers(headers, content_type)
     req_opts = Keyword.merge(client.request_opts, opts)
+    params = opts[:params] || %{}
 
     if Application.get_env(:oauth2, :debug) do
       Logger.debug("""
@@ -33,16 +34,20 @@ defmodule OAuth2.Request do
       """)
     end
 
-    case :hackney.request(method, url, headers, body, req_opts) do
-      {:ok, ref} when is_reference(ref) ->
-        {:ok, ref}
-
-      {:ok, status, headers, ref} when is_reference(ref) ->
-        process_body(client, status, headers, ref)
-
-      {:ok, status, headers, body} when is_binary(body) ->
+    case Tesla.request(http_client(),
+           method: method,
+           url: url,
+           query: params,
+           headers: headers,
+           body: body,
+           opts: [adapter: req_opts]
+         ) do
+      {:ok, %{status: status, headers: headers, body: body}} when is_binary(body) ->
         process_body(client, status, headers, body)
 
+      {:ok, %{body: ref}} when is_reference(ref) ->
+        {:ok, ref}
+
       {:error, reason} ->
         {:error, %Error{reason: reason}}
     end
@@ -80,6 +85,14 @@ defmodule OAuth2.Request do
     end
   end
 
+  defp http_client do
+    adapter = Application.get_env(:oauth2, :adapter, Tesla.Adapter.Httpc)
+
+    middleware = Application.get_env(:oauth2, :middleware, [])
+
+    Tesla.client(middleware, adapter)
+  end
+
   defp process_url(client, url) do
     case String.downcase(url) do
       <<"http://"::utf8, _::binary>> -> url
@@ -88,16 +101,6 @@ defmodule OAuth2.Request do
     end
   end
 
-  defp process_body(client, status, headers, ref) when is_reference(ref) do
-    case :hackney.body(ref) do
-      {:ok, body} ->
-        process_body(client, status, headers, body)
-
-      {:error, reason} ->
-        {:error, %Error{reason: reason}}
-    end
-  end
-
   defp process_body(client, status, headers, body) when is_binary(body) do
     resp = Response.new(client, status, headers, body)
 
@@ -110,12 +113,6 @@ defmodule OAuth2.Request do
     end
   end
 
-  defp process_params(url, nil),
-    do: url
-
-  defp process_params(url, params),
-    do: url <> "?" <> URI.encode_query(params)
-
   defp req_headers(%Client{token: nil} = client, headers),
     do: headers ++ client.headers
 

mix.exs

@@ -27,7 +27,7 @@ defmodule OAuth2.Mixfile do
   end
 
   def application do
-    [applications: [:logger, :hackney]]
+    [extra_applications: [:logger]]
   end
 
   defp dialyzer do
@@ -38,9 +38,10 @@ defmodule OAuth2.Mixfile do
 
   defp deps do
     [
-      {:hackney, "~> 1.13"},
+      {:tesla, "~> 1.4"},
 
       # Test dependencies
+      {:hackney, "~> 1.17", only: [:dev, :test]},
       {:jason, "~> 1.0", only: [:dev, :test]},
       {:bypass, "~> 0.9", only: :test},
       {:plug_cowboy, "~> 1.0", only: :test},

mix.lock

@@ -29,5 +29,6 @@
   "plug_crypto": {:hex, :plug_crypto, "1.0.0", "18e49317d3fa343f24620ed22795ec29d4a5e602d52d1513ccea0b07d8ea7d4d", [:mix], [], "hexpm", "73c1682f0e414cfb5d9b95c8e8cd6ffcfdae699e3b05e1db744e58b7be857759"},
   "ranch": {:hex, :ranch, "1.3.2", "e4965a144dc9fbe70e5c077c65e73c57165416a901bd02ea899cfd95aa890986", [:rebar3], [], "hexpm", "6e56493a862433fccc3aca3025c946d6720d8eedf6e3e6fb911952a7071c357f"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
+  "tesla": {:hex, :tesla, "1.4.4", "bb89aa0c9745190930366f6a2ac612cdf2d0e4d7fff449861baa7875afd797b2", [:mix], [{:castore, "~> 0.1", [hex: :castore, repo: "hexpm", optional: true]}, {:exjsx, ">= 3.0.0", [hex: :exjsx, repo: "hexpm", optional: true]}, {:finch, "~> 0.3", [hex: :finch, repo: "hexpm", optional: true]}, {:fuse, "~> 2.4", [hex: :fuse, repo: "hexpm", optional: true]}, {:gun, "~> 1.3", [hex: :gun, repo: "hexpm", optional: true]}, {:hackney, "~> 1.6", [hex: :hackney, repo: "hexpm", optional: true]}, {:ibrowse, "4.4.0", [hex: :ibrowse, repo: "hexpm", optional: true]}, {:jason, ">= 1.0.0", [hex: :jason, repo: "hexpm", optional: true]}, {:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.0", [hex: :mint, repo: "hexpm", optional: true]}, {:poison, ">= 1.0.0", [hex: :poison, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: true]}], "hexpm", "d5503a49f9dec1b287567ea8712d085947e247cb11b06bc54adb05bfde466457"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
 }

test/oauth2/client_test.exs

@@ -200,9 +200,6 @@ defmodule OAuth2.ClientTest do
 
     {:ok, ref} = Client.get(client, "/api/user/1")
 
-    assert_receive {:hackney_response, ^ref, {:status, 200, "OK"}}
-    assert_receive {:hackney_response, ^ref, {:headers, headers}}
-    assert {_, "8000"} = List.keyfind(headers, "content-length", 0)
     resp_body = stream(ref)
     assert resp_body == body
   end

test/test_helper.exs

@@ -1,3 +1,4 @@
 Application.ensure_all_started(:bypass)
+Application.ensure_all_started(:hackney)
 Application.put_env(:oauth2, :warn_missing_serializer, false)
 ExUnit.start()