UPP Java HTTP Client

Tsvetan Dimitrov

Agenda

  • Retrofit HTTP Client

    • Features

    • Workflow

  • Yet another private library! Why?

  • retrofit-wrapper features

Retrofit HTTP Client

Retrofit Features

  • Type safe API Modelling.

  • Synchronous/Asynchronous API.

  • Custom Interceptors.

  • Built on top of Square's okhttp HTTP client.

Retrofit Workflow / 1

  • Initialize HTTP Client 

OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

Retrofit retrofit = new Retrofit.Builder()
  .baseUrl("https://api.github.com/")
  .addConverterFactory(GsonConverterFactory.create())
  .client(httpClient.build())
  .build();

Retrofit Workflow / 2

  • API Interface Model

public interface UserService {
	 
    @GET("/users")
    Call<List<User>> getUsers(
    	@Query("per_page") int perPage, 
        @Query("page") int page);

    @GET("/users/{username}")
    Call<User> getUser(@Path("username") String username);
}

Retrofit Workflow / 3

  • Initialize API Model Service and call it

UserService service = retrofit.create(UserService.class);
Call<User> call = service.getUser("fonsi");

Retrofit Workflow / 4.1

  • Asyncronous Call

Call<User> callAsync = service.getUser("eugenp");
	 
callAsync.enqueue(new Callback<User>() {
  @Override
  public void onResponse(Call<User> call, Response<User> response) {
  	User user = response.body();
  }

  @Override
  public void onFailure(Call<User> call, Throwable throwable) {
  	System.out.println(throwable);
  }
});

Retrofit Workflow / 4.2

  • Syncronous Call

Response<User> callSync = service.getUser("fonsi").execute();
if (response.isSuccessful()) {
	// return response.body();
} else {
	// handle API error
}

Yet another private library! Why? / 1

Retrofit Wrapper Features

  • Implementation of UPP specifics:

    • Custom Request/Response Logging

    • Transaction ID Propagation

    • API Error Handling

    • Default Request Headers

DEMO

Questions?