[OLINGO-731] Debug interfaces part 1

fit/src/test/java/org/apache/olingo/fit/v4/BatchTestITCase.java

@@ -26,10 +26,8 @@ import static org.junit.Assert.fail;
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.net.URI;
-import java.net.URISyntaxException;
 import java.util.Calendar;
 import java.util.Collection;
-import java.util.HashMap;
 import java.util.Iterator;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;

lib/server-api/src/main/java/org/apache/olingo/server/api/OData.java

@@ -26,6 +26,7 @@ import org.apache.olingo.commons.api.edm.EdmPrimitiveType;
 import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeKind;
 import org.apache.olingo.commons.api.edm.provider.CsdlEdmProvider;
 import org.apache.olingo.commons.api.format.ContentType;
+import org.apache.olingo.server.api.debug.DebugResponseHelper;
 import org.apache.olingo.server.api.deserializer.DeserializerException;
 import org.apache.olingo.server.api.deserializer.FixedFormatDeserializer;
 import org.apache.olingo.server.api.deserializer.ODataDeserializer;
@@ -143,4 +144,12 @@ public abstract class OData {
    * It can be used in Processor implementations.
    */
   public abstract Preferences createPreferences(Collection<String> preferHeaders);
+
+  /**
+   * This method creates a DebugResponseHelper for the given debugFormat. If the format is not supported no
+   * exception is thrown. Instead we give back the implementation for the json format.
+   * @param debugFormat to be used.
+   * @return a debug response serializer
+   */
+  public abstract DebugResponseHelper createDebugResponseHelper(String debugFormat);
 }

lib/server-api/src/main/java/org/apache/olingo/server/api/ODataHttpHandler.java

@@ -21,6 +21,7 @@ package org.apache.olingo.server.api;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.apache.olingo.server.api.debug.DebugSupport;
 import org.apache.olingo.server.api.etag.CustomETagSupport;
 import org.apache.olingo.server.api.processor.Processor;
 import org.apache.olingo.server.api.serializer.CustomContentTypeSupport;
@@ -66,4 +67,10 @@ public interface ODataHttpHandler {
    */
   void register(CustomETagSupport customConcurrencyControlSupport);
 
+  /**
+   * Register the debug support handler
+   * @param debugSupport
+   */
+  void register(DebugSupport debugSupport);
+
 }

lib/server-api/src/main/java/org/apache/olingo/server/api/debug/DebugResponseHelper.java

@@ -0,0 +1,38 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.olingo.server.api.debug;
+
+import org.apache.olingo.server.api.ODataRequest;
+import org.apache.olingo.server.api.ODataResponse;
+
+/**
+ * This class supports applications in creating debug responses.
+ */
+public interface DebugResponseHelper {
+
+  /**
+   * Creates a debug response based on the given parameters. Will never throw an exception.
+   * @param request
+   * @param applicationResponse
+   * @param exception
+   * @return the debug response or the raw application response in case an exception occurred.
+   */
+  ODataResponse createDebugResponse(ODataRequest request, ODataResponse applicationResponse, Exception exception);
+
+}

lib/server-api/src/main/java/org/apache/olingo/server/api/debug/DebugSupport.java

@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.olingo.server.api.debug;
+
+import org.apache.olingo.server.api.OData;
+import org.apache.olingo.server.api.ODataRequest;
+import org.apache.olingo.server.api.ODataResponse;
+
+/**
+ * Register this interface to add debug support to your service.
+ */
+public interface DebugSupport {
+
+  public static final String ODATA_DEBUG_QUERY_PARAMETER = "odata-debug";
+  public static final String ODATA_DEBUG_JSON = "json";
+  public static final String ODATA_DEBUG_HTML = "html";
+  public static final String ODATA_DEBUG_DOWNLOAD = "download";
+
+  void init(OData odata);
+
+  /**
+   * This method should create a debug response and deliver it back to the Olingo library. This method MUST NEVER throw
+   * an exception.
+   * @param debugFormat which is requested via the odata-debug query parameter
+   * @param request object which was send to the server
+   * @param response object which was filled by the application
+   * @param exception which has been thrown. Might be null in case there was no exception
+   * @return a new debug response which will be send to the client
+   */
+  ODataResponse createDebugResponse(String debugFormat, ODataRequest request, ODataResponse response,
+      Exception exception);
+
+}

lib/server-api/src/main/java/org/apache/olingo/server/api/debug/DefaultDebugSupport.java

@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.olingo.server.api.debug;
+
+import org.apache.olingo.server.api.OData;
+import org.apache.olingo.server.api.ODataRequest;
+import org.apache.olingo.server.api.ODataResponse;
+
+/**
+ * Supports the default debug case. Will always deliver a debug response if requested from the server.
+ */
+public class DefaultDebugSupport implements DebugSupport {
+
+  private OData odata;
+
+  @Override
+  public void init(OData odata) {
+    this.odata = odata;
+  }
+
+  @Override
+  public ODataResponse createDebugResponse(String debugFormat, ODataRequest request, ODataResponse applicationResponse,
+      Exception exception) {
+    // Check if debugFormat is supported by the library
+    if (DebugSupport.ODATA_DEBUG_JSON.equalsIgnoreCase(debugFormat)
+        || DebugSupport.ODATA_DEBUG_HTML.equalsIgnoreCase(debugFormat)
+        || DebugSupport.ODATA_DEBUG_DOWNLOAD.equalsIgnoreCase(debugFormat)) {
+      return odata.createDebugResponseHelper(debugFormat).createDebugResponse(request, applicationResponse, exception);
+    } else {
+      // Debug format is not supported by the library by default so in order to avoid an exception we will just give
+      // back the original response from the application.
+      return applicationResponse;
+    }
+  }
+
+}

lib/server-core/src/main/java/org/apache/olingo/server/core/ODataHttpHandlerImpl.java

@@ -6,9 +6,9 @@
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License. You may obtain a copy of the License at
- *
+ * 
  * http://www.apache.org/licenses/LICENSE-2.0
- *
+ * 
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
@@ -40,6 +40,7 @@ import org.apache.olingo.server.api.ODataRequest;
 import org.apache.olingo.server.api.ODataResponse;
 import org.apache.olingo.server.api.ODataLibraryException;
 import org.apache.olingo.server.api.ServiceMetadata;
+import org.apache.olingo.server.api.debug.DebugSupport;
 import org.apache.olingo.server.api.etag.CustomETagSupport;
 import org.apache.olingo.server.api.processor.Processor;
 import org.apache.olingo.server.api.serializer.CustomContentTypeSupport;
@@ -51,7 +52,8 @@ public class ODataHttpHandlerImpl implements ODataHttpHandler {
 
   private static final Logger LOG = LoggerFactory.getLogger(ODataHttpHandlerImpl.class);
 
-  private ODataHandler handler;
+  private final ODataHandler handler;
+  private DebugSupport debugSupport;
   private int split = 0;
 
   public ODataHttpHandlerImpl(final OData odata, final ServiceMetadata serviceMetadata) {
@@ -60,6 +62,7 @@ public class ODataHttpHandlerImpl implements ODataHttpHandler {
 
   @Override
   public void process(final HttpServletRequest request, final HttpServletResponse response) {
+    Exception exception = null;
     ODataRequest odRequest = null;
     ODataResponse odResponse;
     try {
@@ -68,12 +71,27 @@ public class ODataHttpHandlerImpl implements ODataHttpHandler {
       odResponse = handler.process(odRequest);
       // ALL future methods after process must not throw exceptions!
     } catch (Exception e) {
+      exception = e;
       odResponse = handleException(odRequest, e);
     }
 
+    if (debugSupport != null) {
+      String debugFormat = getDebugQueryParameter(request);
+      if (debugFormat != null) {
+        // TODO: Should we be more careful here with response assignement in order to not loose the original response?
+        // TODO: How should we react to exceptions here?
+        odResponse = debugSupport.createDebugResponse(debugFormat, odRequest, odResponse, exception);
+      }
+    }
+
     convertToHttp(response, odResponse);
   }
 
+  private String getDebugQueryParameter(HttpServletRequest request) {
+    // TODO Auto-generated method stub
+    return "";
+  }
+
   @Override
   public void setSplit(final int split) {
     this.split = split;
@@ -132,7 +150,7 @@ public class ODataHttpHandlerImpl implements ODataHttpHandler {
 
   private ODataRequest fillODataRequest(final ODataRequest odRequest, final HttpServletRequest httpRequest,
       final int split)
-          throws ODataLibraryException {
+      throws ODataLibraryException {
     try {
       odRequest.setBody(httpRequest.getInputStream());
       extractHeaders(odRequest, httpRequest);
@@ -243,9 +261,14 @@ public class ODataHttpHandlerImpl implements ODataHttpHandler {
   public void register(final CustomContentTypeSupport customContentTypeSupport) {
     handler.register(customContentTypeSupport);
   }
-  
+
   @Override
   public void register(final CustomETagSupport customConcurrencyControlSupport) {
     handler.register(customConcurrencyControlSupport);
   }
+
+  @Override
+  public void register(final DebugSupport debugSupport) {
+    this.debugSupport = debugSupport;
+  }
 }

lib/server-core/src/main/java/org/apache/olingo/server/core/ODataImpl.java

@@ -29,6 +29,7 @@ import org.apache.olingo.commons.core.edm.primitivetype.EdmPrimitiveTypeFactory;
 import org.apache.olingo.server.api.OData;
 import org.apache.olingo.server.api.ODataHttpHandler;
 import org.apache.olingo.server.api.ServiceMetadata;
+import org.apache.olingo.server.api.debug.DebugResponseHelper;
 import org.apache.olingo.server.api.deserializer.DeserializerException;
 import org.apache.olingo.server.api.deserializer.FixedFormatDeserializer;
 import org.apache.olingo.server.api.deserializer.ODataDeserializer;
@@ -40,6 +41,7 @@ import org.apache.olingo.server.api.serializer.FixedFormatSerializer;
 import org.apache.olingo.server.api.serializer.ODataSerializer;
 import org.apache.olingo.server.api.serializer.SerializerException;
 import org.apache.olingo.server.api.uri.UriHelper;
+import org.apache.olingo.server.core.debug.DebugResponseHelperImpl;
 import org.apache.olingo.server.core.deserializer.FixedFormatDeserializerImpl;
 import org.apache.olingo.server.core.deserializer.json.ODataJsonDeserializer;
 import org.apache.olingo.server.core.etag.ETagHelperImpl;
@@ -139,4 +141,11 @@ public class ODataImpl extends OData {
     return new PreferencesImpl(preferHeaders);
   }
 
+  @Override
+  public DebugResponseHelper createDebugResponseHelper(String debugFormat) {
+    //TODO: What should we do with invalid formats?
+    //TODO: Support more debug formats
+    return new DebugResponseHelperImpl();
+  }
+
 }

lib/server-core/src/main/java/org/apache/olingo/server/core/debug/DebugResponseHelperImpl.java

@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.olingo.server.core.debug;
+
+import org.apache.olingo.server.api.ODataRequest;
+import org.apache.olingo.server.api.ODataResponse;
+import org.apache.olingo.server.api.debug.DebugResponseHelper;
+
+public class DebugResponseHelperImpl implements DebugResponseHelper {
+
+  @Override
+  public ODataResponse
+      createDebugResponse(ODataRequest request, ODataResponse applicationResponse, Exception exception) {
+    return applicationResponse;
+  }
+
+}

lib/server-core/src/main/java/org/apache/olingo/server/core/serializer/json/ODataJsonSerializer.java

@@ -69,7 +69,6 @@ import org.slf4j.LoggerFactory;
 
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
 
 public class ODataJsonSerializer implements ODataSerializer {
 

lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/TechnicalServlet.java

@@ -33,6 +33,7 @@ import javax.servlet.http.HttpSession;
 import org.apache.olingo.server.api.OData;
 import org.apache.olingo.server.api.ODataHttpHandler;
 import org.apache.olingo.server.api.ServiceMetadata;
+import org.apache.olingo.server.api.debug.DefaultDebugSupport;
 import org.apache.olingo.server.api.edmx.EdmxReference;
 import org.apache.olingo.server.api.edmx.EdmxReferenceInclude;
 import org.apache.olingo.server.tecsvc.data.DataProvider;
@@ -79,11 +80,15 @@ public class TechnicalServlet extends HttpServlet {
       }
 
       ODataHttpHandler handler = odata.createHandler(serviceMetadata);
+      // Register processors
       handler.register(new TechnicalEntityProcessor(dataProvider, serviceMetadata));
       handler.register(new TechnicalPrimitiveComplexProcessor(dataProvider, serviceMetadata));
       handler.register(new TechnicalActionProcessor(dataProvider, serviceMetadata));
       handler.register(new TechnicalBatchProcessor(dataProvider));
+      // Register Helper
       handler.register(new ETagSupport());
+      handler.register(new DefaultDebugSupport());
+      // Process the request
       handler.process(request, response);
     } catch (final RuntimeException e) {
       LOG.error("Server Error", e);