Created
March 27, 2019 17:32
-
-
Save rafaeltoledo/41072d07ca04b03c1afed8dfb7c1c9b2 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import kotlinx.coroutines.CompletableDeferred | |
import kotlinx.coroutines.Deferred | |
import retrofit2.Call | |
import retrofit2.CallAdapter | |
import retrofit2.Callback | |
import retrofit2.HttpException | |
import retrofit2.Response | |
import retrofit2.Retrofit | |
import java.lang.reflect.ParameterizedType | |
import java.lang.reflect.Type | |
/** | |
* A [CallAdapter.Factory] for use with Kotlin coroutines. | |
* | |
* Adding this class to [Retrofit] allows you to return [Deferred] from | |
* service methods. | |
* | |
* interface MyService { | |
* @GET("user/me") | |
* Deferred<User> getUser() | |
* } | |
* | |
* There are two configurations supported for the [Deferred] type parameter: | |
* | |
* * Direct body (e.g., `Deferred<User>`) returns the deserialized body for 2XX responses, throws | |
* [HttpException] errors for non-2XX responses, and throws [IOException][java.io.IOException] for | |
* network errors. | |
* * Response wrapped body (e.g., `Deferred<Response<User>>`) returns a [Response] object for all | |
* HTTP responses and throws [IOException][java.io.IOException] for network errors | |
*/ | |
class CoroutineCallAdapterFactory private constructor() : CallAdapter.Factory() { | |
companion object { | |
@JvmStatic @JvmName("create") | |
operator fun invoke() = CoroutineCallAdapterFactory() | |
} | |
override fun get( | |
returnType: Type, | |
annotations: Array<out Annotation>, | |
retrofit: Retrofit | |
): CallAdapter<*, *>? { | |
if (Deferred::class.java != getRawType(returnType)) { | |
return null | |
} | |
if (returnType !is ParameterizedType) { | |
throw IllegalStateException( | |
"Deferred return type must be parameterized as Deferred<Foo> or Deferred<out Foo>") | |
} | |
val responseType = getParameterUpperBound(0, returnType) | |
val rawDeferredType = getRawType(responseType) | |
return if (rawDeferredType == Response::class.java) { | |
if (responseType !is ParameterizedType) { | |
throw IllegalStateException( | |
"Response must be parameterized as Response<Foo> or Response<out Foo>") | |
} | |
ResponseCallAdapter<Any>(getParameterUpperBound(0, responseType)) | |
} else { | |
BodyCallAdapter<Any>(responseType) | |
} | |
} | |
private class BodyCallAdapter<T>( | |
private val responseType: Type | |
) : CallAdapter<T, Deferred<T>> { | |
override fun responseType() = responseType | |
override fun adapt(call: Call<T>): Deferred<T> { | |
val deferred = CompletableDeferred<T>() | |
deferred.invokeOnCompletion { | |
if (deferred.isCancelled) { | |
call.cancel() | |
} | |
} | |
call.enqueue(object : Callback<T> { | |
override fun onFailure(call: Call<T>, t: Throwable) { | |
deferred.completeExceptionally(t) | |
} | |
override fun onResponse(call: Call<T>, response: Response<T>) { | |
if (response.isSuccessful) { | |
deferred.complete(response.body() ?: Unit as T) | |
} else { | |
deferred.completeExceptionally(HttpException(response)) | |
} | |
} | |
}) | |
return deferred | |
} | |
} | |
private class ResponseCallAdapter<T>( | |
private val responseType: Type | |
) : CallAdapter<T, Deferred<Response<T>>> { | |
override fun responseType() = responseType | |
override fun adapt(call: Call<T>): Deferred<Response<T>> { | |
val deferred = CompletableDeferred<Response<T>>() | |
deferred.invokeOnCompletion { | |
if (deferred.isCancelled) { | |
call.cancel() | |
} | |
} | |
call.enqueue(object : Callback<T> { | |
override fun onFailure(call: Call<T>, t: Throwable) { | |
deferred.completeExceptionally(t) | |
} | |
override fun onResponse(call: Call<T>, response: Response<T>) { | |
deferred.complete(response) | |
} | |
}) | |
return deferred | |
} | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment