Improve error messages for invalid media types (#1607)

Show separate error messages for invalid partial media types and application/json if it unsupported for the url.

scm-webapp/src/main/java/sonia/scm/api/v2/InvalidAcceptHeaderFilter.java

@@ -0,0 +1,114 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.api.v2;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Strings;
+import sonia.scm.TransactionId;
+import sonia.scm.api.v2.resources.ErrorDto;
+
+import javax.annotation.Priority;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.container.ContainerRequestContext;
+import javax.ws.rs.container.ContainerResponseContext;
+import javax.ws.rs.container.ContainerResponseFilter;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.ext.Provider;
+import java.util.List;
+
+@Provider
+@Priority(ResponseFilterPriorities.INVALID_ACCEPT_HEADER)
+public class InvalidAcceptHeaderFilter implements ContainerResponseFilter {
+
+  @VisibleForTesting
+  static final String CODE_PARTIAL_WILDCARD = "ChSSf2AFs1";
+
+  private static final String MESSAGE_PARTIAL_WILDCARD = "Partial wildcards for media types are not supported. " +
+    "Please use a valid content type or a non partial wildcard such as application/*.";
+
+  @VisibleForTesting
+  static final String CODE_APPLICATION_JSON = "7bSSf4F381";
+  private static final String MESSAGE_APPLICATION_JSON = "Media type application/json is not supported on this url. " +
+    "Please use a valid vnd media type.";
+
+  @Override
+  public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext)  {
+    if (isNoMatchForAcceptHeader(responseContext)) {
+      List<MediaType> acceptableMediaTypes = requestContext.getAcceptableMediaTypes();
+      if (containsPartialWildcard(acceptableMediaTypes)) {
+        responseContext.setEntity(createPartialWildcardError());
+      } else if (containsApplicationJson(acceptableMediaTypes)) {
+        responseContext.setEntity(createApplicationJsonError());
+      }
+    }
+  }
+
+  private boolean containsApplicationJson(List<MediaType> acceptableMediaTypes) {
+    return acceptableMediaTypes.stream().anyMatch(this::isApplicationJson);
+  }
+
+  private ErrorDto createPartialWildcardError() {
+    ErrorDto errorDto = new ErrorDto();
+    errorDto.setErrorCode(CODE_PARTIAL_WILDCARD);
+    errorDto.setMessage(MESSAGE_PARTIAL_WILDCARD);
+    TransactionId.get().ifPresent(errorDto::setTransactionId);
+    return errorDto;
+  }
+
+  private ErrorDto createApplicationJsonError() {
+    ErrorDto errorDto = new ErrorDto();
+    errorDto.setErrorCode(CODE_APPLICATION_JSON);
+    errorDto.setMessage(MESSAGE_APPLICATION_JSON);
+    TransactionId.get().ifPresent(errorDto::setTransactionId);
+    return errorDto;
+  }
+
+  private boolean containsPartialWildcard(List<MediaType> acceptableMediaTypes) {
+    return acceptableMediaTypes.stream().anyMatch(this::isPartialWildcard);
+  }
+
+  private boolean isPartialWildcard(MediaType mediaType) {
+    if (mediaType.getSubtype() != null) {
+      return mediaType.getSubtype().contains("*+json");
+    }
+    return true;
+  }
+
+  private boolean isApplicationJson(MediaType mediaType) {
+    return "application".equals(mediaType.getType()) && "json".equals(mediaType.getSubtype());
+  }
+
+  private boolean isNoMatchForAcceptHeader(ContainerResponseContext responseContext) {
+    if (responseContext.getStatus() == HttpServletResponse.SC_NOT_ACCEPTABLE) {
+      Object entity = responseContext.getEntity();
+      if (entity instanceof ErrorDto) {
+        String message = ((ErrorDto) entity).getMessage();
+        return Strings.nullToEmpty(message).startsWith("RESTEASY003635");
+      }
+    }
+    return false;
+  }
+
+}

scm-webapp/src/main/java/sonia/scm/api/v2/ResponseFilterPriorities.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.api.v2;
 
 
@@ -40,6 +40,8 @@ final class ResponseFilterPriorities {
   static final int JSON_MARSHALLING = Priorities.USER + 1000;
   static final int FIELD_FILTER = Priorities.USER;
 
+  static final int INVALID_ACCEPT_HEADER = JSON_MARSHALLING + 1000;
+
   private ResponseFilterPriorities() {
   }
 }