Make requests with body one shot

The proxer api can't handle retransmission of bodies and this way we
enforce it to never happen.

Author: rubengees

gradle/dependencies.gradle

@@ -10,6 +10,7 @@ dependencies {
     kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshiVersion"
 
     testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testImplementation "org.junit.jupiter:junit-jupiter-params:$junitVersion"
     testImplementation "org.assertj:assertj-core:$assertjVersion"
     testImplementation "org.mockito:mockito-core:$mockitoVersion"
     testImplementation "com.squareup.okhttp3:okhttp-tls:$okHttpVersion"

gradle/versions.gradle

@@ -15,11 +15,11 @@ ext {
     buildConfigPluginVersion = "1.1.8"
 
     retrofitVersion = "2.5.0"
-    okHttpVersion = "3.13.1"
+    okHttpVersion = "3.14.0"
     moshiVersion = "1.8.0"
     moshiLazyAdaptersVersion = "2.2"
 
     junitVersion = "5.4.0"
     assertjVersion = "3.11.1"
-    mockitoVersion = "2.24.0"
+    mockitoVersion = "2.25.1"
 }

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

@@ -36,6 +36,7 @@ import me.proxer.library.internal.adapter.UnitAdapter
 import me.proxer.library.internal.interceptor.HeaderInterceptor
 import me.proxer.library.internal.interceptor.HttpsEnforcingInterceptor
 import me.proxer.library.internal.interceptor.LoginTokenInterceptor
+import me.proxer.library.internal.interceptor.OneShotInterceptor
 import me.proxer.library.util.ProxerUrls
 import okhttp3.CertificatePinner
 import okhttp3.OkHttpClient
@@ -214,7 +215,8 @@ class ProxerApi private constructor(retrofit: Retrofit) {
                             0, listOf(
                                 HeaderInterceptor(apiKey, buildUserAgent()),
                                 LoginTokenInterceptor(buildLoginTokenManager()),
-                                HttpsEnforcingInterceptor()
+                                HttpsEnforcingInterceptor(),
+                                OneShotInterceptor()
                             )
                         )
                     }

library/src/main/kotlin/me/proxer/library/internal/OneShotDelegatingRequestBody.kt

@@ -0,0 +1,17 @@
+package me.proxer.library.internal
+
+import okhttp3.RequestBody
+import okio.BufferedSink
+
+/**
+ * @author Ruben Gees
+ */
+internal class OneShotDelegatingRequestBody(private val delegate: RequestBody) : RequestBody() {
+
+    override fun contentType() = delegate.contentType()
+    override fun contentLength() = delegate.contentLength()
+    override fun writeTo(sink: BufferedSink) = delegate.writeTo(sink)
+    override fun isDuplex() = delegate.isDuplex
+
+    override fun isOneShot() = true
+}

library/src/main/kotlin/me/proxer/library/internal/interceptor/OneShotInterceptor.kt

@@ -0,0 +1,31 @@
+package me.proxer.library.internal.interceptor
+
+import me.proxer.library.internal.OneShotDelegatingRequestBody
+import me.proxer.library.util.ProxerUrls
+import okhttp3.Interceptor
+import okhttp3.Response
+
+/**
+ * @author Ruben Gees
+ */
+internal class OneShotInterceptor : Interceptor {
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val oldRequest = chain.request()
+        val body = oldRequest.body()
+
+        if (ProxerUrls.hasProxerHost(oldRequest.url())) {
+            val newRequest = if (body != null) {
+                oldRequest.newBuilder()
+                    .method(oldRequest.method(), OneShotDelegatingRequestBody(body))
+                    .build()
+            } else {
+                oldRequest
+            }
+
+            return chain.proceed(newRequest)
+        } else {
+            throw IllegalArgumentException("Only use ProxerLib's OkHttp instance with Proxer.Me URLs!")
+        }
+    }
+}

library/src/test/kotlin/me/proxer/library/internal/interceptor/OneShotInterceptorTest.kt

@@ -0,0 +1,49 @@
+package me.proxer.library.internal.interceptor
+
+import okhttp3.Interceptor
+import okhttp3.MediaType
+import okhttp3.Request
+import okhttp3.RequestBody
+import okhttp3.Response
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.mockito.ArgumentCaptor
+import org.mockito.Mockito.`when`
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.notNull
+import org.mockito.Mockito.verify
+
+class OneShotInterceptorTest {
+
+    private val interceptor = OneShotInterceptor()
+    private val chain = mock(Interceptor.Chain::class.java)
+
+    @Test
+    fun testOneShotSetForRequestsWithBodies() {
+        val requestCaptor = ArgumentCaptor.forClass(Request::class.java)
+        val body = RequestBody.create(MediaType.parse("text/plain"), "hello")
+        val request = Request.Builder().post(body).url("https://proxer.me/fake").build()
+
+        `when`(chain.request()).thenReturn(request)
+        `when`(chain.proceed(notNull())).thenReturn(mock(Response::class.java))
+
+        interceptor.intercept(chain)
+
+        verify(chain).proceed(requestCaptor.capture())
+        assertThat(requestCaptor.value.body()?.isOneShot).isTrue()
+    }
+
+    @Test
+    fun testNoModificationForRequestsWithoutBodies() {
+        val requestCaptor = ArgumentCaptor.forClass(Request::class.java)
+        val request = Request.Builder().url("https://proxer.me/fake").build()
+
+        `when`(chain.request()).thenReturn(request)
+        `when`(chain.proceed(notNull())).thenReturn(mock(Response::class.java))
+
+        interceptor.intercept(chain)
+
+        verify(chain).proceed(requestCaptor.capture())
+        assertThat(requestCaptor.value).isEqualTo(request)
+    }
+}