Add selective interception. (#279)

* Add selective interception.
* Update README.md.
* Align formatting in README with other points.
* Avoid header name duplication.
* Strip interception header also in the no-op library.

README.md

@@ -119,7 +119,7 @@ try {
 
 ### Redact-Header 👮‍♂️
 
-**Warning** The data generated and stored when using Chucker may contain sensitive information such as Authorization or Cookie headers, and the contents of request and response bodies. 
+**Warning** The data generated and stored when using Chucker may contain sensitive information such as Authorization or Cookie headers, and the contents of request and response bodies.
 
 It is intended for **use during development**, and not in release builds or other production deployments.
 
@@ -129,6 +129,30 @@ You can redact headers that contain sensitive information by calling `redactHead
 interceptor.redactHeader("Auth-Token", "User-Session");
 ```
 
+### Skip-Inspection ️🕵️
+
+If you need to selectively skip Chucker inspection on some endpoints or on particular requests you can add a special header - `Skip-ChuckerInterceptor: true`. This will inform Chucker to not process this request. Chucker will also strip this header from any request before sending it to a server.
+
+If you use `OkHttp` directly, create requests like below.
+
+```kotlin
+val request = Request.Builder().url(serverUrl)
+        .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "true")
+        .build()
+
+client.newCall(request).execute()
+```
+
+If you are a `Retrofit` user you can configure it per endpoint like this.
+
+```kotlin
+fun Service {
+    @GET("/")
+    @Headers(Chucker.SKIP_INTERCEPTOR_HEADER)
+    fun networkRequest(): Unit
+}
+```
+
 ## Migrating 🚗
 
 If you're migrating **from [Chuck](https://github.com/jgilfelt/chuck) to Chucker**, please refer to this [migration guide](/docs/migrating-from-chuck.md).

library-no-op/build.gradle

@@ -25,6 +25,13 @@ artifacts {
 dependencies {
     implementation "com.squareup.okhttp3:okhttp:$okhttp3Version"
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion"
+
+    testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
+    testImplementation "org.junit.jupiter:junit-jupiter-params:$junitVersion"
+    testImplementation "io.mockk:mockk:$mockkVersion"
+    testImplementation "com.squareup.okhttp3:mockwebserver:$okhttp3Version"
+    testImplementation "com.google.truth:truth:$truthVersion"
 }
 
 apply from: rootProject.file('gradle/gradle-mvn-push.gradle')

library-no-op/src/main/java/com/chuckerteam/chucker/api/Chucker.kt

@@ -11,6 +11,9 @@ object Chucker {
     const val SCREEN_HTTP = 1
     const val SCREEN_ERROR = 2
 
+    const val SKIP_INTERCEPTOR_HEADER_NAME = "Skip-Chucker-Interceptor"
+    const val SKIP_INTERCEPTOR_HEADER = "$SKIP_INTERCEPTOR_HEADER_NAME: true"
+
     @Suppress("MayBeConst ") // https://github.com/ChuckerTeam/chucker/pull/169#discussion_r362341353
     val isOp = false
 

library-no-op/src/main/java/com/chuckerteam/chucker/api/ChuckerInterceptor.kt

@@ -21,7 +21,9 @@ class ChuckerInterceptor @JvmOverloads constructor(
 
     @Throws(IOException::class)
     override fun intercept(chain: Interceptor.Chain): Response {
-        val request = chain.request()
+        val request = chain.request().newBuilder()
+            .removeHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)
+            .build()
         return chain.proceed(request)
     }
 }

library-no-op/src/test/java/com/chuckerteam/chucker/api/ChuckerInterceptorTest.kt

@@ -0,0 +1,47 @@
+package com.chuckerteam.chucker.api
+
+import android.content.Context
+import com.google.common.truth.Truth.assertThat
+import io.mockk.every
+import io.mockk.mockk
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import org.junit.Rule
+import org.junit.jupiter.api.Test
+
+class ChuckerInterceptorTest {
+    @get:Rule val server = MockWebServer()
+    private val serverUrl = server.url("/") // Starts server implicitly
+    private val mockContext = mockk<Context> {
+        every { getString(any()) } returns ""
+    }
+    private val client = OkHttpClient.Builder()
+        .addInterceptor(ChuckerInterceptor(mockContext))
+        .build()
+
+    @Test
+    fun skipChuckerHeader_isNotAvailableForTheServerRequest() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "true")
+            .build()
+
+        val response = client.newCall(request).execute()
+
+        assertThat(response.request().header(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)).isNull()
+    }
+
+    @Test
+    fun doNotSkipChuckerHeader_isNotAvailableForTheServerRequest() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "false")
+            .build()
+
+        val response = client.newCall(request).execute()
+
+        assertThat(response.request().header(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)).isNull()
+    }
+}

library/src/main/java/com/chuckerteam/chucker/api/Chucker.kt

@@ -15,6 +15,9 @@ object Chucker {
     const val SCREEN_HTTP = 1
     const val SCREEN_ERROR = 2
 
+    const val SKIP_INTERCEPTOR_HEADER_NAME = "Skip-Chucker-Interceptor"
+    const val SKIP_INTERCEPTOR_HEADER = "$SKIP_INTERCEPTOR_HEADER_NAME: true"
+
     /**
      * Check if this instance is the operation one or no-op.
      * @return `true` if this is the operation instance.

library/src/main/java/com/chuckerteam/chucker/api/ChuckerInterceptor.kt

@@ -47,7 +47,14 @@ class ChuckerInterceptor @JvmOverloads constructor(
 
     @Throws(IOException::class)
     override fun intercept(chain: Interceptor.Chain): Response {
-        val request = chain.request()
+        val request = chain.request().newBuilder()
+            .removeHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)
+            .build()
+
+        if (chain.request().header(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)?.toBoolean() == true) {
+            return chain.proceed(request)
+        }
+
         val response: Response
         val transaction = HttpTransaction()
 

library/src/test/java/com/chuckerteam/chucker/api/ChuckerInterceptorTest.kt

@@ -3,10 +3,9 @@ package com.chuckerteam.chucker.api
 import android.content.Context
 import com.chuckerteam.chucker.getResourceFile
 import com.chuckerteam.chucker.internal.data.entity.HttpTransaction
+import com.google.common.truth.Truth.assertThat
 import io.mockk.every
 import io.mockk.mockk
-import junit.framework.TestCase.assertEquals
-import junit.framework.TestCase.assertTrue
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import okhttp3.mockwebserver.MockResponse
@@ -15,7 +14,7 @@ import okio.Buffer
 import okio.ByteString
 import okio.GzipSink
 import org.junit.Rule
-import org.junit.Test
+import org.junit.jupiter.api.Test
 
 class ChuckerInterceptorTest {
     @get:Rule val server = MockWebServer()
@@ -45,7 +44,7 @@ class ChuckerInterceptorTest {
 
         client.newCall(request).execute()
 
-        assertEquals(expectedBody, ByteString.of(*transaction!!.responseImageData!!))
+        assertThat(expectedBody).isEqualTo(ByteString.of(*transaction!!.responseImageData!!))
     }
 
     @Test
@@ -57,7 +56,7 @@ class ChuckerInterceptorTest {
 
         val responseBody = client.newCall(request).execute().body()!!.source().readByteString()
 
-        assertEquals(expectedBody, responseBody)
+        assertThat(expectedBody).isEqualTo(responseBody)
     }
 
     @Test
@@ -71,8 +70,8 @@ class ChuckerInterceptorTest {
 
         client.newCall(request).execute()
 
-        assertTrue(transaction!!.isResponseBodyPlainText)
-        assertEquals("Hello, world!", transaction!!.responseBody)
+        assertThat(transaction!!.isResponseBodyPlainText).isTrue()
+        assertThat(transaction!!.responseBody).isEqualTo("Hello, world!")
     }
 
     @Test
@@ -86,6 +85,78 @@ class ChuckerInterceptorTest {
 
         val responseBody = client.newCall(request).execute().body()!!.source().readByteString()
 
-        assertEquals("Hello, world!", responseBody.utf8())
+        assertThat(responseBody.utf8()).isEqualTo("Hello, world!")
+    }
+
+    @Test
+    fun requestThatShouldBeSkipped_isNotProcessedByChucker() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "true")
+            .build()
+
+        client.newCall(request).execute()
+
+        assertThat(transaction).isNull()
+    }
+
+    @Test
+    fun requestThatShouldBeSkipped_isDeliveredToTheEndConsumer() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "true")
+            .build()
+
+        val body = client.newCall(request).execute().body()!!.string()
+
+        assertThat(body).isEqualTo("Hello, world!")
+    }
+
+    @Test
+    fun requestThatShouldNotBeSkipped_isProcessedByChucker() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "false")
+            .build()
+
+        client.newCall(request).execute()
+
+        assertThat(transaction!!.responseBody).isEqualTo("Hello, world!")
+    }
+
+    @Test
+    fun requestThatShouldNotBeSkipped_isDeliveredToTheEndConsumer() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "false")
+            .build()
+
+        val body = client.newCall(request).execute().body()!!.string()
+
+        assertThat(body).isEqualTo("Hello, world!")
+    }
+
+    @Test
+    fun skipChuckerHeader_isNotAvailableForTheServerRequest() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "true")
+            .build()
+
+        val response = client.newCall(request).execute()
+
+        assertThat(response.request().header(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)).isNull()
+    }
+
+    @Test
+    fun doNotSkipChuckerHeader_isNotAvailableForTheServerRequest() {
+        server.enqueue(MockResponse().setBody("Hello, world!"))
+        val request = Request.Builder().url(serverUrl)
+            .addHeader(Chucker.SKIP_INTERCEPTOR_HEADER_NAME, "false")
+            .build()
+
+        val response = client.newCall(request).execute()
+
+        assertThat(response.request().header(Chucker.SKIP_INTERCEPTOR_HEADER_NAME)).isNull()
     }
 }