[PM-20306] Migrate Auth Token Interceptor (#5065)

network/build.gradle.kts

@@ -2,8 +2,10 @@ import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 plugins {
     alias(libs.plugins.android.library)
+    alias(libs.plugins.hilt)
     alias(libs.plugins.kotlin.android)
     alias(libs.plugins.kotlin.serialization)
+    alias(libs.plugins.ksp)
 }
 
 android {
@@ -46,6 +48,8 @@ dependencies {
     implementation(project(":core"))
 
     implementation(libs.androidx.core.ktx)
+    implementation(libs.google.hilt.android)
+    ksp(libs.google.hilt.compiler)
     implementation(libs.kotlinx.serialization)
     implementation(libs.square.okhttp)
     implementation(libs.square.okhttp.logging)

network/src/main/kotlin/com/bitwarden/network/interceptor/AuthTokenInterceptor.kt

@@ -0,0 +1,33 @@
+package com.bitwarden.network.interceptor
+
+import com.bitwarden.network.util.HEADER_KEY_AUTHORIZATION
+import com.bitwarden.network.util.HEADER_VALUE_BEARER_PREFIX
+import okhttp3.Interceptor
+import okhttp3.Response
+import java.io.IOException
+import javax.inject.Singleton
+
+/**
+ * Interceptor responsible for adding the auth token(Bearer) to API requests.
+ */
+@Singleton
+class AuthTokenInterceptor(
+    private val authTokenProvider: AuthTokenProvider,
+) : Interceptor {
+    private val missingTokenMessage = "Auth token is missing!"
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val token = authTokenProvider.getActiveAccessTokenOrNull()
+            ?: throw IOException(IllegalStateException(missingTokenMessage))
+        val request = chain
+            .request()
+            .newBuilder()
+            .addHeader(
+                name = HEADER_KEY_AUTHORIZATION,
+                value = "${HEADER_VALUE_BEARER_PREFIX}$token",
+            )
+            .build()
+        return chain
+            .proceed(request)
+    }
+}

network/src/main/kotlin/com/bitwarden/network/interceptor/AuthTokenProvider.kt

@@ -0,0 +1,12 @@
+package com.bitwarden.network.interceptor
+
+/**
+ * A provider for all the functionality needed to properly refresh the users access token.
+ */
+interface AuthTokenProvider {
+
+    /**
+     * The currently active user's access token.
+     */
+    fun getActiveAccessTokenOrNull(): String?
+}

network/src/test/kotlin/com/bitwarden/network/interceptor/AuthTokenInterceptorTest.kt

@@ -0,0 +1,52 @@
+package com.bitwarden.network.interceptor
+
+import io.mockk.every
+import io.mockk.mockk
+import junit.framework.TestCase.assertEquals
+import okhttp3.Request
+import org.junit.Assert.assertThrows
+import org.junit.Test
+import java.io.IOException
+import javax.inject.Singleton
+
+@Singleton
+class AuthTokenInterceptorTest {
+    private val mockAuthTokenProvider = mockk<AuthTokenProvider> {
+        every { getActiveAccessTokenOrNull() } returns null
+    }
+    private val interceptor: AuthTokenInterceptor = AuthTokenInterceptor(
+        authTokenProvider = mockAuthTokenProvider,
+    )
+    private val request: Request = Request
+        .Builder()
+        .url("http://localhost")
+        .build()
+
+    @Test
+    fun `intercept should add the auth token when set`() {
+        every { mockAuthTokenProvider.getActiveAccessTokenOrNull() } returns ACCESS_TOKEN
+
+        val response = interceptor.intercept(
+            chain = FakeInterceptorChain(request = request),
+        )
+        assertEquals(
+            "Bearer $ACCESS_TOKEN",
+            response.request.header("Authorization"),
+        )
+    }
+
+    @Test
+    fun `intercept should throw an exception when an auth token is missing`() {
+        val throwable = assertThrows(IOException::class.java) {
+            interceptor.intercept(
+                chain = FakeInterceptorChain(request = request),
+            )
+        }
+        assertEquals(
+            "Auth token is missing!",
+            throwable.cause?.message,
+        )
+    }
+}
+
+private const val ACCESS_TOKEN: String = "access_token"