Handle empty and missing response bodies. (#250)

* Add failing test cases.
* Remove unused const.
* Gzip response body if it was gunzipped.
* Add test cases for regular bodies in Chucker.
* Fix rule formatting.
* Use proper name for application interceptor.
* Return original response downstream.
* Account for no content with gzip encoding.
* Use Truth for Chucker tests.
* Honor empty plaintext bodies.
* Revert changes to HttpBinClient.
* Update library/src/test/java/com/chuckerteam/chucker/ChuckerInterceptorDelegate.kt
* Update library/src/main/java/com/chuckerteam/chucker/internal/support/OkHttpUtils.kt
Co-authored-by: Nicola Corti <corti.nico@gmail.com>
Co-authored-by: Volodymyr Buberenko <vbuberen@users.noreply.github.com>

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

@@ -8,6 +8,7 @@ import com.chuckerteam.chucker.internal.support.IOUtils
 import com.chuckerteam.chucker.internal.support.TeeSource
 import com.chuckerteam.chucker.internal.support.contentLength
 import com.chuckerteam.chucker.internal.support.contentType
+import com.chuckerteam.chucker.internal.support.hasBody
 import com.chuckerteam.chucker.internal.support.isGzipped
 import java.io.File
 import java.io.IOException
@@ -179,7 +180,7 @@ class ChuckerInterceptor internal constructor(
         transaction: HttpTransaction
     ): Response {
         val responseBody = response.body()
-        if (responseBody == null) {
+        if (!response.hasBody() || responseBody == null) {
             collector.onResponseReceived(transaction)
             return response
         }

library/src/main/java/com/chuckerteam/chucker/internal/support/OkHttpUtils.kt

@@ -1,12 +1,37 @@
 package com.chuckerteam.chucker.internal.support
 
+import java.net.HttpURLConnection.HTTP_NOT_MODIFIED
+import java.net.HttpURLConnection.HTTP_NO_CONTENT
+import java.net.HttpURLConnection.HTTP_OK
 import okhttp3.Headers
 import okhttp3.Request
 import okhttp3.Response
 
+private const val HTTP_CONTINUE = 100
+
+/** Returns true if the response must have a (possibly 0-length) body. See RFC 7231.  */
+internal fun Response.hasBody(): Boolean {
+    // HEAD requests never yield a body regardless of the response headers.
+    if (request().method() == "HEAD") {
+        return false
+    }
+
+    val responseCode = code()
+    if ((responseCode < HTTP_CONTINUE || responseCode >= HTTP_OK) &&
+        (responseCode != HTTP_NO_CONTENT) &&
+        (responseCode != HTTP_NOT_MODIFIED)
+    ) {
+        return true
+    }
+
+    // If the Content-Length or Transfer-Encoding headers disagree with the response code, the
+    // response is malformed. For best compatibility, we honor the headers.
+    return ((contentLength > 0) || isChunked)
+}
+
 internal val Response.contentLength: Long
     get() {
-        return this.header("Content-Length")?.toLongOrNull() ?: -1
+        return this.header("Content-Length")?.toLongOrNull() ?: -1L
     }
 
 internal val Response.isChunked: Boolean

library/src/main/java/com/chuckerteam/chucker/internal/support/TeeSource.kt

@@ -64,7 +64,10 @@ internal class TeeSource(
         sideStream.close()
         upstream.close()
         if (isUpstreamExhausted) {
-            callback.onSuccess(sideChannel)
+            // Failure might have occurred due to exceeding limit.
+            if (!isFailure) {
+                callback.onSuccess(sideChannel)
+            }
         } else {
             callSideChannelFailure(IOException("Upstream was not fully consumed"))
         }

library/src/test/java/com/chuckerteam/chucker/ChuckerInterceptorDelegate.kt

@@ -0,0 +1,59 @@
+package com.chuckerteam.chucker
+
+import android.content.Context
+import com.chuckerteam.chucker.api.ChuckerCollector
+import com.chuckerteam.chucker.api.ChuckerInterceptor
+import com.chuckerteam.chucker.internal.data.entity.HttpTransaction
+import com.chuckerteam.chucker.internal.support.FileFactory
+import io.mockk.every
+import io.mockk.mockk
+import java.util.concurrent.CopyOnWriteArrayList
+import java.util.concurrent.atomic.AtomicLong
+import okhttp3.Interceptor
+import okhttp3.Response
+
+internal class ChuckerInterceptorDelegate(
+    fileFactory: FileFactory,
+    maxContentLength: Long = 250000L,
+    headersToRedact: Set<String> = emptySet()
+) : Interceptor {
+    private val idGenerator = AtomicLong()
+    private val transactions = CopyOnWriteArrayList<HttpTransaction>()
+
+    private val mockContext = mockk<Context> {
+        every { getString(any()) } returns ""
+    }
+    private val mockCollector = mockk<ChuckerCollector> {
+        every { onRequestSent(any()) } returns Unit
+        every { onResponseReceived(any()) } answers {
+            val transaction = (args[0] as HttpTransaction)
+            transaction.id = idGenerator.getAndIncrement()
+            transactions.add(transaction)
+        }
+    }
+
+    private val chucker = ChuckerInterceptor(
+        context = mockContext,
+        collector = mockCollector,
+        maxContentLength = maxContentLength,
+        headersToRedact = headersToRedact,
+        fileFactory = fileFactory
+    )
+
+    internal fun expectTransaction(): HttpTransaction {
+        if (transactions.isEmpty()) {
+            throw AssertionError("Expected transaction but was empty.")
+        }
+        return transactions.removeAt(0)
+    }
+
+    internal fun expectNoTransactions() {
+        if (transactions.isNotEmpty()) {
+            throw AssertionError("Expected no transactions but found ${transactions.size}")
+        }
+    }
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        return chucker.intercept(chain)
+    }
+}

library/src/test/java/com/chuckerteam/chucker/TestUtils.kt

@@ -2,8 +2,11 @@ package com.chuckerteam.chucker
 
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
+import com.chuckerteam.chucker.internal.support.hasBody
 import java.io.File
+import okhttp3.Response
 import okio.Buffer
+import okio.ByteString
 import okio.Okio
 
 fun getResourceFile(file: String): Buffer {
@@ -12,6 +15,14 @@ fun getResourceFile(file: String): Buffer {
     }
 }
 
+fun Response.readByteStringBody(): ByteString? {
+    return if (hasBody()) {
+        body()?.source()?.use { it.readByteString() }
+    } else {
+        null
+    }
+}
+
 fun <T> LiveData<T>.test(test: LiveDataRecord<T>.() -> Unit) {
     val observer = RecordingObserver<T>()
     observeForever(observer)