ReactiveX와 Retrofit 같이 쓰기!

Retofit의 Call 부분을 다시 되집어 보면 onFailure와 OnResponse가 있다

어디선가 많이 본 형식인데

맞다 ReactiveX와 비슷하게 생겼다!
즉슨! 그말은 RxJav와 Retrofit을 함께 쓸 수 있지 않을까..?

오늘은 두가지 방법으로 구현을 해볼 것이다

1. 직접 코딩
2. 라이브러리 사용

---

Gradle Dependency

// reactive
implementation 'io.reactivex.rxjava2:rxjava:2.2.6'

// retrofit2
implementation 'com.squareup.retrofit2:retrofit:2.3.0'
implementation 'com.squareup.retrofit2:converter-gson:2.1.0'
implementation 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'

// okHttp3
implementation 'com.squareup.okhttp3:okhttp:3.10.0'
implementation 'com.squareup.okhttp3:logging-interceptor:3.4.2'

---

먼저 이전 코드를 살펴보자

GitHubClient().getService().getRepos("You-Kkomi") 
        .enqueue(object : Callback, retrofit2.Callback<List> { 
            override fun onFailure(call: Call<List>, t: Throwable) { 
                Log.e("retrofit2", t.message) 
            } 

            override fun onResponse(call: Call<List>, response: Response<List>) { 
                if (!response.isSuccessful) 
                    return 

                response.body()!!.forEach { Log.d("retrofit2", it.name) } 
            } 
        }) 

RxJava에서 Subject를 쓰면 간단하게 구현이 될 것 같다.

class GtihubManager { 

    fun getRepoList(): BehaviorSubject<List> { 

        val behaviorSubject = BehaviorSubject.create<List>() 

        GitHubClient().getService().getRepos("You-Kkomi") 
            .enqueue(object : Callback, retrofit2.Callback<List> { 
                override fun onFailure(call: Call<List>, t: Throwable) { 
                    behaviorSubject.onError(t) 
                } 

                override fun onResponse(call: Call<List>, response: Response<List>) { 
                    if (!response.isSuccessful) { 
                        behaviorSubject.onError(Exception("isNotSuccessful")) 
                        return 
                    } 

                    behaviorSubject.onNext(response.body()!!) 
                    behaviorSubject.onComplete() 
                } 
            }) 

        return behaviorSubject 
    } 

} 

클래스 명은 생각이 나지 않아 대충 지었으니 그냥 넘어가도록하자..
손쉽게 behavior를 사용하여서 코드를 작성해 보았다.

GithubManager().getRepoList().subscribe { it.log() } 

D/retrofit: [
GitHubRepo(name=HF_Server),
GitHubRepo(name=MC_DevLibrary),
GitHubRepo(name=MC_DevLibrary1710),
GitHubRepo(name=Refactoring-MVVM-using-AAC),
GitHubRepo(name=You-Kkomi.github.io)
] 

잘 들어온다...

하지만 매번 rxjava를 쓰자고 저런식으로 말들어야 한다니... 매우 귀찮은 일이 아닐 수가 없다..
그냥 call 쓰고말지...

이를 Retrofit도 눈치를 차린건지 지원을 한다!
그것도 단 1줄!

class GitHubClient { 

    companion object { 
        val BASE_URL = "https://api.github.com" 
    } 

    fun getService(): GithubService { 
        return Retrofit.Builder() 
            .baseUrl(BASE_URL) 
            .addConverterFactory(GsonConverterFactory.create()) 
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create()) // 
            .build() 
            .create(GithubService::class.java) 
    } 

} 

끝?
아니다 interface 부분도 변경해 주어야 한다.

interface GithubService { 

    @GET("/users/{owner}/repos") 
    fun getRepos(@Path("owner") owner: String): Single<List> 

} 

GitHubClient().getService().getReposToSingle("You-Kkomi") 
        .subscribeOn(Schedulers.io()) 
        .observeOn(AndroidSchedulers.mainThread()) 
        .subscribe( 
            { repo -> repo.log() }, 
            { error -> error.log() } 
        ) 

먼저 Retrofit작업은 백그라운드에서 시켜야 함으로 subscribeOn을 io로
subscirbe는 데이터를 받아서 안드로이드 View에 쓸것임으로 Android의 mainThread로 받아준다.

실행하면 아래와 같이 정상적으로 데이터가 들어오는 것을 볼 수 있다.

D/retrofit: [
GitHubRepo(name=HF_Server),
GitHubRepo(name=MC_DevLibrary),
GitHubRepo(name=MC_DevLibrary1710),
GitHubRepo(name=Refactoring-MVVM-using-AAC),
GitHubRepo(name=You-Kkomi.github.io)
] 

손쉽게 구현을 한 Retrofit과 RxJava!