compile adapters only when available

lib/tesla/adapter/hackney.ex

@@ -1,42 +1,44 @@
-defmodule Tesla.Adapter.Hackney do
-  def call(env, opts) do
-    with  {:ok, status, headers, body} <- request(env, opts || []) do
-      %{env | status:   status,
-              headers:  headers,
-              body:     body}
+if Code.ensure_loaded?(:hackney) do
+  defmodule Tesla.Adapter.Hackney do
+    def call(env, opts) do
+      with  {:ok, status, headers, body} <- request(env, opts || []) do
+        %{env | status:   status,
+                headers:  headers,
+                body:     body}
+      end
     end
-  end
 
-  defp request(env, opts) do
-    request(
-      env.method,
-      Tesla.build_url(env.url, env.query),
-      Enum.into(env.headers, []),
-      env.body,
-      opts ++ env.opts
-    )
-  end
-  defp request(method, url, headers, %Stream{} = body, opts), do: request_stream(method, url, headers, body, opts)
-  defp request(method, url, headers, body, opts) when is_function(body), do: request_stream(method, url, headers, body, opts)
-  defp request(method, url, headers, body, opts) do
-    handle :hackney.request(method, url, headers, body || '', opts)
-  end
+    defp request(env, opts) do
+      request(
+        env.method,
+        Tesla.build_url(env.url, env.query),
+        Enum.into(env.headers, []),
+        env.body,
+        opts ++ env.opts
+      )
+    end
+    defp request(method, url, headers, %Stream{} = body, opts), do: request_stream(method, url, headers, body, opts)
+    defp request(method, url, headers, body, opts) when is_function(body), do: request_stream(method, url, headers, body, opts)
+    defp request(method, url, headers, body, opts) do
+      handle :hackney.request(method, url, headers, body || '', opts)
+    end
 
 
-  defp request_stream(method, url, headers, body, opts) do
-    with {:ok, ref} <- :hackney.request(method, url, headers, :stream, opts) do
-      for data <- body, do: :ok = :hackney.send_body(ref, data)
-      handle :hackney.start_response(ref)
-    else
-      e -> handle(e)
+    defp request_stream(method, url, headers, body, opts) do
+      with {:ok, ref} <- :hackney.request(method, url, headers, :stream, opts) do
+        for data <- body, do: :ok = :hackney.send_body(ref, data)
+        handle :hackney.start_response(ref)
+      else
+        e -> handle(e)
+      end
     end
-  end
 
-  defp handle({:error, _} = error), do: error
-  defp handle({:ok, status, headers}), do: {:ok, status, headers, []}
-  defp handle({:ok, status, headers, ref}) do
-    with {:ok, body} <- :hackney.body(ref) do
-      {:ok, status, headers, body}
+    defp handle({:error, _} = error), do: error
+    defp handle({:ok, status, headers}), do: {:ok, status, headers, []}
+    defp handle({:ok, status, headers, ref}) do
+      with {:ok, body} <- :hackney.body(ref) do
+        {:ok, status, headers, body}
+      end
     end
   end
 end

lib/tesla/adapter/ibrowse.ex

@@ -1,20 +1,22 @@
-defmodule Tesla.Adapter.Ibrowse do
-  def call(env, opts) do
-    with {:ok, status, headers, body} <- request(env, opts || []) do
-      %{env | status:   status,
-              headers:  headers,
-              body:     body}
+if Code.ensure_loaded?(:ibrowse) do
+  defmodule Tesla.Adapter.Ibrowse do
+    def call(env, opts) do
+      with {:ok, status, headers, body} <- request(env, opts || []) do
+        %{env | status:   status,
+                headers:  headers,
+                body:     body}
+      end
     end
-  end
 
-  defp request(env, opts) do
-    body = env.body || []
-    :ibrowse.send_req(
-      Tesla.build_url(env.url, env.query) |> to_char_list,
-      Enum.into(env.headers, []),
-      env.method,
-      body,
-      opts
-    )
+    defp request(env, opts) do
+      body = env.body || []
+      :ibrowse.send_req(
+        Tesla.build_url(env.url, env.query) |> to_char_list,
+        Enum.into(env.headers, []),
+        env.method,
+        body,
+        opts
+      )
+    end
   end
 end