Add extra fields in ServiceException

endpoints-framework/build.gradle

@@ -110,6 +110,7 @@ dependencies {
   testCompile project(':test-utils')
   testCompile group: 'junit', name: 'junit', version: junitVersion
   testCompile group: 'org.mockito', name: 'mockito-core', version: mockitoVersion
+  testCompile group: 'org.skyscreamer', name: 'jsonassert', version: jsonassertVersion
   testCompile group: 'com.google.truth', name: 'truth', version: truthVersion
   testCompile group: 'com.google.appengine', name: 'appengine-testing', version: appengineVersion
   testCompile group: 'com.google.appengine', name: 'appengine-api-stubs', version: appengineVersion

endpoints-framework/src/main/java/com/google/api/server/spi/ServiceException.java

@@ -15,6 +15,12 @@
  */
 package com.google.api.server.spi;
 
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import com.google.common.flogger.FluentLogger;
+
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.logging.Level;
 
@@ -24,10 +30,16 @@
  */
 public class ServiceException extends Exception {
 
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  /** Reserved keywords, cannot be set as an extra field name. */
+  public static final ImmutableList<String> EXTRA_FIELDS_RESERVED_NAMES = ImmutableList.of("domain", "message", "reason");
+
   protected final int statusCode;
   protected final String reason;
   protected final String domain;
   protected Level logLevel;
+  private final Map<String, Object> extraFields = new HashMap<>();
 
   public ServiceException(int statusCode, String statusMessage) {
     super(statusMessage);
@@ -102,6 +114,64 @@ public Map<String, String> getHeaders() {
     return null;
   }
 
+  /**
+   * Associates to this exception an extra field as a field name/value pair. If a field
+   * with the same name was previously set, the old value is replaced by the specified
+   * value.
+   * @return this
+   * @throws NullPointerException if {@code fieldName} is {@code null}.
+   * @throws IllegalArgumentException if {@code fieldName} is one of the reserved field
+   *         names {@link #EXTRA_FIELDS_RESERVED_NAMES}.
+   */
+  public ServiceException putExtraField(String fieldName, String value) {
+    return putExtraFieldInternal(fieldName, value);
+  }
+
+  /**
+   * Associates to this exception an extra field as a field name/value pair. If a field
+   * with the same name was previously set, the old value is replaced by the specified
+   * value.
+   * @return this
+   * @throws NullPointerException if {@code fieldName} is {@code null}.
+   * @throws IllegalArgumentException if {@code fieldName} is one of the reserved field
+   *         names {@link #EXTRA_FIELDS_RESERVED_NAMES}.
+   */
+  public ServiceException putExtraField(String fieldName, Boolean value) {
+    return putExtraFieldInternal(fieldName, value);
+  }
+
+  /**
+   * Associates to this exception an extra field as a field name/value pair. If a field
+   * with the same name was previously set, the old value is replaced by the specified
+   * value.
+   * @return this
+   * @throws NullPointerException if {@code fieldName} is {@code null}.
+   * @throws IllegalArgumentException if {@code fieldName} is one of the reserved field
+   *         names {@link #EXTRA_FIELDS_RESERVED_NAMES}.
+   */
+  public ServiceException putExtraField(String fieldName, Number value) {
+    return putExtraFieldInternal(fieldName, value);
+  }
+
+  private ServiceException putExtraFieldInternal(String fieldName, Object value) {
+    Preconditions.checkNotNull(fieldName);
+    Preconditions.checkArgument(!EXTRA_FIELDS_RESERVED_NAMES.contains(fieldName), "The field name '%s' is reserved", fieldName);
+    final Object previousValue = extraFields.put(fieldName, value);
+    if (previousValue != null) {
+      logger.atFine().log("Replaced extra field %s: %s => %s", fieldName, previousValue, value);
+    }
+    return this;
+  }
+
+  /**
+   * Gets the extra fields. The extra fields are returned in an unmodifiable map,
+   * each field name/value pair is a map entry. The map is empty if no extra field
+   * has been added.
+   */
+  public final Map<String, Object> getExtraFields() {
+    return Collections.unmodifiableMap(extraFields);
+  }
+
   public Level getLogLevel() {
     return logLevel == null ? getDefaultLoggingLevel(statusCode) : logLevel;
   }

endpoints-framework/src/main/java/com/google/api/server/spi/response/RestResponseResultWriter.java

@@ -23,6 +23,7 @@
 import com.google.common.base.Strings;
 
 import java.io.IOException;
+import java.util.Map;
 
 import javax.servlet.http.HttpServletResponse;
 
@@ -67,16 +68,19 @@ public void writeError(ServiceException e) throws IOException {
         e.getReason() : errorMap.getReason(e.getStatusCode());
     String domain = !Strings.isNullOrEmpty(e.getDomain()) ?
         e.getDomain() : errorMap.getDomain(e.getStatusCode());
-    write(code, e.getHeaders(), createError(code, reason, domain, e.getMessage()));
+    write(code, e.getHeaders(), createError(code, reason, domain, e.getMessage(), e.getExtraFields()));
   }
 
-  private Object createError(int code, String reason, String domain, String message) {
+  private Object createError(int code, String reason, String domain, String message, Map<String, Object> extraFields) {
     ObjectNode topLevel = objectMapper.createObjectNode();
     ObjectNode topError = objectMapper.createObjectNode();
     ObjectNode error = objectMapper.createObjectNode();
     error.put("domain", domain);
     error.put("reason", reason);
     error.put("message", message);
+    for (Map.Entry<String, Object> extraField : extraFields.entrySet()) {
+      error.putPOJO(extraField.getKey(), extraField.getValue());
+    }
     topError.set("errors", objectMapper.createArrayNode().add(error));
     topError.put("code", code);
     topError.put("message", message);

endpoints-framework/src/test/java/com/google/api/server/spi/ServiceExceptionTest.java

@@ -1,20 +1,91 @@
 package com.google.api.server.spi;
 
 import static com.google.common.truth.Truth.assertThat;
+import static java.lang.Boolean.TRUE;
 
+import com.google.api.server.spi.response.BadRequestException;
+import com.google.api.server.spi.response.ConflictException;
 import com.google.api.server.spi.response.UnauthorizedException;
+
+import java.util.Map;
 import java.util.logging.Level;
+
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
 public class ServiceExceptionTest {
+
+  @Rule
+  public ExpectedException expectedException = ExpectedException.none();
+
   @Test
   public void testWithLogLevel() {
     UnauthorizedException ex = new UnauthorizedException("");
     assertThat(ex.getLogLevel()).isEqualTo(Level.INFO);
     assertThat(ServiceException.withLogLevel(ex, Level.WARNING).getLogLevel())
         .isEqualTo(Level.WARNING);
   }
-}
+
+  @Test
+  public void testExtraFields() {
+    UnauthorizedException ex = new UnauthorizedException("");
+    ex.putExtraField("isAdmin", TRUE)
+      .putExtraField("userId", Integer.valueOf(12))
+      .putExtraField("userName", "John Doe");
+    Map<String, Object> extraFields = ex.getExtraFields();
+    assertThat(extraFields.size()).isEqualTo(3);
+    assertThat(extraFields.get("isAdmin")).isEqualTo(TRUE);
+    assertThat(extraFields.get("userId")).isEqualTo(12);
+    assertThat(extraFields.get("userName")).isEqualTo("John Doe");
+  }
+
+  @Test(expected = NullPointerException.class)
+  public void testExtraFields_nameNull() {
+    new BadRequestException("").putExtraField(null, "value not null");
+  }
+
+  @Test
+  public void testExtraFields_valueNull_allowed() {
+    UnauthorizedException ex = new UnauthorizedException("");
+    ex.putExtraField("isAdmin", (String) null);
+    Map<String, Object> extraFields = ex.getExtraFields();
+    assertThat(extraFields.size()).isEqualTo(1);
+    assertThat(extraFields.get("isAdmin")).isNull();
+  }
+
+  @Test
+  public void testExtraFields_overrideValue_keepLast() {
+    UnauthorizedException ex = new UnauthorizedException("");
+    ex.putExtraField("isAdmin", "YES");
+    ex.putExtraField("isAdmin", TRUE);
+    Map<String, Object> extraFields = ex.getExtraFields();
+    assertThat(extraFields.size()).isEqualTo(1);
+    assertThat(extraFields.get("isAdmin")).isEqualTo(TRUE);
+  }
+
+  @Test
+  public void testExtraFields_ReservedNameDomain_forbidden() {
+    assertExtraFields_ReservedName_forbidden("domain");
+  }
+
+  @Test
+  public void testExtraFields_ReservedNameMessage_forbidden() {
+    assertExtraFields_ReservedName_forbidden("message");
+  }
+
+  @Test
+  public void testExtraFields_ReservedNameReason_forbidden() {
+    assertExtraFields_ReservedName_forbidden("reason");
+  }
+
+  private void assertExtraFields_ReservedName_forbidden(String fieldName) {
+    expectedException.expect(IllegalArgumentException.class);
+    expectedException.expectMessage("The field name '" + fieldName + "' is reserved");
+
+    new ConflictException("Fails", "no extra " + fieldName).putExtraField(fieldName, "some other " + fieldName);
+  }
+}

endpoints-framework/src/test/java/com/google/api/server/spi/response/RestResponseResultWriterTest.java

@@ -16,6 +16,8 @@
 package com.google.api.server.spi.response;
 
 import static com.google.common.truth.Truth.assertThat;
+import static java.lang.Boolean.FALSE;
+import static java.lang.Boolean.TRUE;
 
 import com.google.api.server.spi.ObjectMapperUtil;
 import com.google.api.server.spi.ServiceException;
@@ -27,6 +29,7 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
+import org.skyscreamer.jsonassert.JSONAssert;
 import org.springframework.mock.web.MockHttpServletResponse;
 
 /**
@@ -219,4 +222,51 @@ private void writeError(boolean enableExceptionCompatibility, String customReaso
     assertThat(innerError.path("domain").asText()).isEqualTo(expectedDomain);
     assertThat(innerError.path("reason").asText()).isEqualTo(expectedReason);
   }
+
+  @Test
+  public void writeError_extraFields() throws Exception {
+    MockHttpServletResponse response = new MockHttpServletResponse();
+    RestResponseResultWriter writer = new RestResponseResultWriter(response, null, true /* prettyPrint */,
+        true /* addContentLength */, true /* enableExceptionCompatibility */);
+
+    ServiceException serviceException = new ServiceException(400, "customMessage", "customReason", "customDomain");
+    // Extra field string
+    serviceException.putExtraField("someExtraString", "string1")
+                    .putExtraField("someNullString", (String)null);
+    // Extra field number
+    serviceException.putExtraField("someExtraInt", Integer.valueOf(12))
+                    .putExtraField("someExtraFloat", Float.valueOf(1.2f))
+                    .putExtraField("someNullNumber", (Number)null);
+    // Extra field boolean
+    serviceException.putExtraField("someExtraTrue", TRUE)
+                    .putExtraField("someExtraFalse", FALSE)
+                    .putExtraField("someNullBoolean", (Boolean)null);
+    // Extra field, keys are equals to reserved keywords when ignoring case
+    serviceException.putExtraField("Domain", TRUE)
+                    .putExtraField("REASON", Long.valueOf(1234567890))
+                    .putExtraField("messAge", "hello world!");
+
+    String expectedError = "{\"error\": {\"errors\": [{" +
+        "  \"domain\": \"customDomain\"," +
+        "  \"reason\": \"customReason\"," +
+        "  \"message\": \"customMessage\"," +
+        "  \"someExtraString\": \"string1\"," +
+        "  \"someNullString\": null," +
+        "  \"someExtraInt\": 12," +
+        "  \"someExtraFloat\": 1.2," +
+        "  \"someNullNumber\": null," +
+        "  \"someExtraTrue\": true," +
+        "  \"someExtraFalse\": false," +
+        "  \"someNullBoolean\": null," +
+        "  \"Domain\": true," +
+        "  \"REASON\": \"1234567890\"," +
+        "  \"messAge\": \"hello world!\"" +
+        " }]," +
+        " \"code\": 400," +
+        " \"message\": \"customMessage\"" +
+        "}}";
+
+    writer.writeError(serviceException);
+    JSONAssert.assertEquals(expectedError, response.getContentAsString(), true);
+  }
 }

gradle.properties

@@ -21,5 +21,6 @@ floggerVersion=0.3.1
 
 junitVersion=4.12
 mockitoVersion=1.10.19
+jsonassertVersion=1.5.0
 truthVersion=0.28
 springtestVersion=3.2.16.RELEASE