# Criando o cliente da Marvel
Vamos lá mais uma vez. Para termos a conexão com um serviço, precisamos criar essa conexão. Aqui estamos chamando ele de Client e vivera no contexto de integrações. Criaremos o arquivo `lib/coffee_shop/integrations/marvel_comics/client.ex` utilizando o mesmo padrão do cliente do café já criado.
Iremos decompor essa chamada do tesla para dentro de nosso novo modulo utilizando os padrões estabelecidos nos capitulos anteriores
```elixir
Tesla.get("https://gateway.marvel.com/v1/public/comics?apikey=12345&hash=7EE341DFFE88E697114117AA51E1A210&ts=1")
```
* Utilizaremos uma função privada para configurar nosso cliente Tesla de forma práticas para os testes.
* Colocaremos a url base em um função isolada, decidindo chamar ela de `https://gateway.marvel.com/v1/public` uma vez que utilizaremos sempre essa base.
* Criaremos uma função publica que fara a requisição
{% code title="lib/coffee\_shop/integrations/marvel\_comics/client.ex" lineNumbers="true" %}
```elixir
defmodule CoffeeShop.Integrations.MarvelComics.Client do
def comics(opts \\ []) do
base_url = Keyword.get(opts, :base_url, base_url())
opts
|> new_client()
|> Tesla.get("#{base_url}/v1/public/comics")
end
defp new_client(_opts) do
middlewares = []
Tesla.client(middlewares)
end
defp base_url() do
"https://gateway.marvel.com"
end
end
```
{% endcode %}
Essa é a cara base. Precisamos de uma teste para ele.
defmodule CoffeeShop.Integrations.MarvelComics.ClientTest do
use ExUnit.Case
alias CoffeeShop.Integrations.MarvelComics.Client
setup do
bypass = Bypass.open(port: 3000)
{:ok, bypass: bypass}
end
describe "comics/0" do
test "respond a list of comics", %{bypass: bypass} do
response = ""
Bypass.expect_once(bypass, "GET", "/v1/public/comics", fn conn ->
assert %{
"apiKey" => _,
"hash" => _,
"ts" => _
} = conn.query_params
Plug.Conn.resp(conn, 200, response)
end)
opts = [
base_url: "http://localhost:3000"
]
assert {:ok, response} = Client.comics(opts)
assert response.status == 200
end
end
end
Nesse teste, queremos garantir que a requisição chamada é do recurso que queremos. Também queremos garantir que os parâmetros *hash*, *api\_key* e *ts* estão sendo enviados juntos.
```
mix test test/coffee_shop/integrations/marvel_comics/client_test.exs
```
> mix test test/coffee_shop/integrations/marvel_comics/client_test.exs main [df2d2e3] modified untracked
Compiling 1 file (.ex)
....
16:33:14.917 [error] #PID<0.407.0> running Bypass.Plug (connection #PID<0.406.0>, stream id 1) terminated
Server: localhost:3000 (http)
Request: GET /v1/public/comics
** (exit) an exception was raised:
** (ExUnit.AssertionError)
match (=) failed
code: assert %{"apiKey" => _, "hash" => _, "ts" => _} = conn.query_params
left: %{"apiKey" => _, "hash" => _, "ts" => _}
right: %{}
test/coffee_shop/integrations/marvel_comics/client_test.exs:16: anonymous fn/1 in CoffeeShop.Integrations.MarvelComics.ClientTest."test comics/0 respond a list of comics"/1
(bypass 2.1.0) lib/bypass/plug.ex:14: Bypass.Plug.call/2
(plug_cowboy 2.7.1) lib/plug/cowboy/handler.ex:11: Plug.Cowboy.Handler.init/2
(cowboy 2.12.0) /root/code/study/api/coffee_shop/deps/cowboy/src/cowboy_handler.erl:37: :cowboy_handler.execute/2
(cowboy 2.12.0) /root/code/study/api/coffee_shop/deps/cowboy/src/cowboy_stream_h.erl:306: :cowboy_stream_h.execute/3
(cowboy 2.12.0) /root/code/study/api/coffee_shop/deps/cowboy/src/cowboy_stream_h.erl:295: :cowboy_stream_h.request_process/3
(stdlib 5.0.2) proc_lib.erl:241: :proc_lib.init_p_do_apply/3
1) test comics/0 respond a list of comics (CoffeeShop.Integrations.MarvelComics.ClientTest)
test/coffee_shop/integrations/marvel_comics/client_test.exs:12
Assertion with == failed
code: assert response.status == 200
left: 500
right: 200
stacktrace:
test/coffee_shop/integrations/marvel_comics/client_test.exs:30: (test)
Como vimos na leitura do endpoint, precisamos enviar os três parâmetros para conseguir realizar a chamada. Vamos adiciona-los.
Para adicionar `query_params`, *Tesla* possui um [middleware ](https://hexdocs.pm/tesla/Tesla.Middleware.Query.html)que facilita o trabalho para nós. Vamos usa-lo.
defmodule CoffeeShop.Integrations.MarvelComics.Client do
def comics(opts \\ []) do
base_url = Keyword.get(opts, :base_url, base_url())
opts
|> new_client()
|> Tesla.get("#{base_url}/v1/public/comics")
end
defp new_client(_opts) do
middlewares = [
{Tesla.Middleware.Query, [apikey: "12345", hash: "7EE341DFFE88E697114117AA51E1A210", ts: 1]}
]
Tesla.client(middlewares)
end
defp base_url() do
"https://gateway.marvel.com"
end
end
Decidimos seguir o mesmo padrão adotado no cliente do café e tiramos proveito disso. Basta adicionar o middleware direto na criação do *Tesla.client*. Com isso, podemos rodar os teses novamente.
```
mix test test/coffee_shop/integrations/marvel_comics/client_test.exs
```
```elixir
> mix test test/coffee_shop/integrations/marvel_comics/client_test.exs main [df2d2e3] modified untracked
.
Finished in 0.1 seconds (0.00s async, 0.1s sync)
1 test, 0 failures
```
Com isso garantimos que estamos passando todos os dados que precisamos para realizar a requisição.
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