Clarify availability of a Response Body in FeignException (#1149)

Fixes #920

FeignException may contain the data from the response if the response is available and contains data.  However, the method `content` is ambiguious and does not reveal it's intent.  User's have expressed confusion as to if it is for the Request or the Response.

This change adds a new method `responseBody` to addresse this.  Use of content is now `@deprecated`.

Author: kdavisk6

core/src/main/java/feign/FeignException.java

@@ -22,10 +22,12 @@
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.nio.Buffer;
+import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.charset.Charset;
 import java.util.Collection;
 import java.util.Map;
+import java.util.Optional;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -36,7 +38,7 @@ public class FeignException extends RuntimeException {
       "request should not be null";
   private static final long serialVersionUID = 0;
   private int status;
-  private byte[] content;
+  private byte[] responseBody;
   private Request request;
 
   protected FeignException(int status, String message, Throwable cause) {
@@ -45,10 +47,10 @@ protected FeignException(int status, String message, Throwable cause) {
     this.request = null;
   }
 
-  protected FeignException(int status, String message, Throwable cause, byte[] content) {
+  protected FeignException(int status, String message, Throwable cause, byte[] responseBody) {
     super(message, cause);
     this.status = status;
-    this.content = content;
+    this.responseBody = responseBody;
     this.request = null;
   }
 
@@ -58,10 +60,10 @@ protected FeignException(int status, String message) {
     this.request = null;
   }
 
-  protected FeignException(int status, String message, byte[] content) {
+  protected FeignException(int status, String message, byte[] responseBody) {
     super(message);
     this.status = status;
-    this.content = content;
+    this.responseBody = responseBody;
     this.request = null;
   }
 
@@ -72,10 +74,10 @@ protected FeignException(int status, String message, Request request, Throwable
   }
 
   protected FeignException(
-      int status, String message, Request request, Throwable cause, byte[] content) {
+      int status, String message, Request request, Throwable cause, byte[] responseBody) {
     super(message, cause);
     this.status = status;
-    this.content = content;
+    this.responseBody = responseBody;
     this.request = checkRequestNotNull(request);
   }
 
@@ -85,10 +87,10 @@ protected FeignException(int status, String message, Request request) {
     this.request = checkRequestNotNull(request);
   }
 
-  protected FeignException(int status, String message, Request request, byte[] content) {
+  protected FeignException(int status, String message, Request request, byte[] responseBody) {
     super(message);
     this.status = status;
-    this.content = content;
+    this.responseBody = responseBody;
     this.request = checkRequestNotNull(request);
   }
 
@@ -100,8 +102,27 @@ public int status() {
     return this.status;
   }
 
+  /**
+   * The Response Body, if present.
+   *
+   * @return the body of the response.
+   * @deprecated use {@link #responseBody()} instead.
+   */
+  @Deprecated
   public byte[] content() {
-    return this.content;
+    return this.responseBody;
+  }
+
+  /**
+   * The Response body.
+   *
+   * @return an Optional wrapping the response body.
+   */
+  public Optional<ByteBuffer> responseBody() {
+    if (this.responseBody == null) {
+      return Optional.empty();
+    }
+    return Optional.of(ByteBuffer.wrap(this.responseBody));
   }
 
   public Request request() {
@@ -113,8 +134,8 @@ public boolean hasRequest() {
   }
 
   public String contentUTF8() {
-    if (content != null) {
-      return new String(content, UTF_8);
+    if (responseBody != null) {
+      return new String(responseBody, UTF_8);
     } else {
       return "";
     }

core/src/test/java/feign/FeignExceptionTest.java

@@ -13,10 +13,59 @@
  */
 package feign;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
 import org.junit.Test;
 
 public class FeignExceptionTest {
 
+  @Test
+  public void canCreateWithRequestAndResponse() {
+    Request request =
+        Request.create(
+            Request.HttpMethod.GET,
+            "/home",
+            Collections.emptyMap(),
+            "data".getBytes(StandardCharsets.UTF_8),
+            StandardCharsets.UTF_8,
+            null);
+
+    Response response =
+        Response.builder()
+            .status(400)
+            .body("response".getBytes(StandardCharsets.UTF_8))
+            .request(request)
+            .build();
+
+    FeignException exception =
+        FeignException.errorReading(request, response, new IOException("socket closed"));
+    assertThat(exception.responseBody()).isNotEmpty();
+    assertThat(exception.hasRequest()).isTrue();
+    assertThat(exception.request()).isNotNull();
+  }
+
+  @Test
+  public void canCreateWithRequestOnly() {
+    Request request =
+        Request.create(
+            Request.HttpMethod.GET,
+            "/home",
+            Collections.emptyMap(),
+            "data".getBytes(StandardCharsets.UTF_8),
+            StandardCharsets.UTF_8,
+            null);
+
+    FeignException exception =
+        FeignException.errorExecuting(request, new IOException("connection timeout"));
+    assertThat(exception.responseBody()).isEmpty();
+    assertThat(exception.content()).isNullOrEmpty();
+    assertThat(exception.hasRequest()).isTrue();
+    assertThat(exception.request()).isNotNull();
+  }
+
   @Test(expected = NullPointerException.class)
   public void nullRequestShouldThrowNPEwThrowable() {
     new Derived(404, "message", null, new Throwable());