Add coroutine support

Author: rubengees

README.md

@@ -80,6 +80,15 @@ api.notifications().news()
 
 As you can see in the example above, the individual endpoints also allow for various options.
 
+##### Coroutines
+
+It is also possible to execute requests in a coroutine context when using Kotlin. Use the `await` extension function on
+the `ProxerCall`:
+
+```kt
+val result = api.notifications().news().build().await()
+```
+
 ### Cancelling a request
 
 You might want to cancel a request, especially if using on `Android`:

gradle/dependencies.gradle

@@ -8,11 +8,15 @@ dependencies {
 
     implementation "com.serjltt.moshi:moshi-lazy-adapters:$moshiLazyAdaptersVersion"
 
+    compileOnly "org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinCoroutinesVersion"
+
     runtimeOnly "com.squareup.okio:okio:$okioVersion"
 
     kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshiVersion"
     kaptTest "com.squareup.moshi:moshi-kotlin-codegen:$moshiVersion"
 
+    testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinCoroutinesVersion"
+
     testImplementation "org.junit.jupiter:junit-jupiter:$junitVersion"
     testImplementation "org.junit.jupiter:junit-jupiter-params:$junitVersion"
 

gradle/versions.gradle

@@ -5,6 +5,7 @@ ext {
     gradleVersion = "6.7.1"
 
     kotlinVersion = "1.4.21"
+    kotlinCoroutinesVersion = "1.4.2"
     dokkaVersion = "1.4.20"
 
     jacocoVersion = "0.8.6"

library/src/main/kotlin/me/proxer/library/KotlinExtensions.kt

@@ -0,0 +1,26 @@
+package me.proxer.library
+
+import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlin.coroutines.resume
+import kotlin.coroutines.resumeWithException
+
+suspend fun <T : Any> ProxerCall<T>.await(): T {
+    return suspendCancellableCoroutine { continuation ->
+        continuation.invokeOnCancellation {
+            cancel()
+        }
+
+        enqueue(
+            { result ->
+                if (result != null) {
+                    continuation.resume(result)
+                } else {
+                    continuation.resumeWithException(NullPointerException())
+                }
+            },
+            { error ->
+                continuation.resumeWithException(error)
+            }
+        )
+    }
+}

library/src/test/kotlin/me/proxer/library/KotlinExtensionsKtTest.kt

@@ -0,0 +1,45 @@
+package me.proxer.library
+
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.async
+import kotlinx.coroutines.runBlocking
+import okhttp3.mockwebserver.MockResponse
+import org.amshove.kluent.AnyException
+import org.amshove.kluent.coInvoking
+import org.amshove.kluent.shouldBe
+import org.amshove.kluent.shouldBeEqualTo
+import org.amshove.kluent.shouldNotThrow
+import org.amshove.kluent.shouldThrow
+import org.amshove.kluent.with
+import org.junit.jupiter.api.Test
+
+class KotlinExtensionsKtTest : ProxerTest() {
+
+    @Test
+    fun testAwait(): Unit = runBlocking {
+        server.enqueue(MockResponse().setBody(fromResource("news.json")))
+
+        coInvoking { api.notifications.news().build().await() } shouldNotThrow AnyException
+    }
+
+    @Test
+    fun testAwaitWithError(): Unit = runBlocking {
+        server.enqueue(MockResponse().setBody(fromResource("news.json")).setResponseCode(404))
+
+        coInvoking { api.notifications.news().build().await() } shouldThrow ProxerException::class with
+            { errorType shouldBe ProxerException.ErrorType.IO }
+    }
+
+    @Test
+    fun testCancel(): Unit = runBlocking {
+        server.enqueue(MockResponse().setBody(fromResource("news.json")))
+
+        with(async { api.notifications.news().build().await() }) {
+            cancel()
+
+            coInvoking { await() } shouldThrow CancellationException::class
+        }
+
+        server.requestCount shouldBeEqualTo 0
+    }
+}

library/src/test/kotlin/me/proxer/library/ProxerTest.kt

@@ -7,7 +7,6 @@ import okhttp3.tls.internal.TlsUtil
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.BeforeEach
 import java.util.concurrent.TimeUnit
-import javax.net.ssl.HostnameVerifier
 
 /**
  * Base class for all integration tests. It provides a ready to use [MockWebServer],
@@ -24,7 +23,7 @@ abstract class ProxerTest {
 
     protected val client: OkHttpClient = OkHttpClient.Builder()
         .addInterceptor(MockWebServerUrlRewriteInterceptor(server))
-        .hostnameVerifier(HostnameVerifier { _, _ -> true })
+        .hostnameVerifier { _, _ -> true }
         .sslSocketFactory(tls.sslSocketFactory(), tls.trustManager)
         .connectTimeout(500, TimeUnit.MILLISECONDS)
         .writeTimeout(500, TimeUnit.MILLISECONDS)