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The Core Camel Java DSL based router
/**
* 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.camel.processor.binding;
import java.util.Locale;
import java.util.Map;
import org.apache.camel.AsyncCallback;
import org.apache.camel.AsyncProcessor;
import org.apache.camel.CamelContext;
import org.apache.camel.CamelContextAware;
import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.Route;
import org.apache.camel.processor.MarshalProcessor;
import org.apache.camel.processor.UnmarshalProcessor;
import org.apache.camel.spi.DataFormat;
import org.apache.camel.spi.RestConfiguration;
import org.apache.camel.support.ServiceSupport;
import org.apache.camel.support.SynchronizationAdapter;
import org.apache.camel.util.AsyncProcessorHelper;
import org.apache.camel.util.ExchangeHelper;
import org.apache.camel.util.MessageHelper;
import org.apache.camel.util.ObjectHelper;
import org.apache.camel.util.ServiceHelper;
/**
* A {@link org.apache.camel.Processor} that binds the REST DSL incoming and outgoing messages
* from sources of json or xml to Java Objects.
*
* The binding uses {@link org.apache.camel.spi.DataFormat} for the actual work to transform
* from xml/json to Java Objects and reverse again.
*/
public class RestBindingProcessor extends ServiceSupport implements AsyncProcessor {
private final CamelContext camelContext;
private final AsyncProcessor jsonUnmarshal;
private final AsyncProcessor xmlUnmarshal;
private final AsyncProcessor jsonMarshal;
private final AsyncProcessor xmlMarshal;
private final String consumes;
private final String produces;
private final String bindingMode;
private final boolean skipBindingOnErrorCode;
private final boolean enableCORS;
private final Map corsHeaders;
public RestBindingProcessor(CamelContext camelContext, DataFormat jsonDataFormat, DataFormat xmlDataFormat,
DataFormat outJsonDataFormat, DataFormat outXmlDataFormat,
String consumes, String produces, String bindingMode,
boolean skipBindingOnErrorCode, boolean enableCORS,
Map corsHeaders) {
this.camelContext = camelContext;
if (jsonDataFormat != null) {
this.jsonUnmarshal = new UnmarshalProcessor(jsonDataFormat);
} else {
this.jsonUnmarshal = null;
}
if (outJsonDataFormat != null) {
this.jsonMarshal = new MarshalProcessor(outJsonDataFormat);
} else if (jsonDataFormat != null) {
this.jsonMarshal = new MarshalProcessor(jsonDataFormat);
} else {
this.jsonMarshal = null;
}
if (xmlDataFormat != null) {
this.xmlUnmarshal = new UnmarshalProcessor(xmlDataFormat);
} else {
this.xmlUnmarshal = null;
}
if (outXmlDataFormat != null) {
this.xmlMarshal = new MarshalProcessor(outXmlDataFormat);
} else if (xmlDataFormat != null) {
this.xmlMarshal = new MarshalProcessor(xmlDataFormat);
} else {
this.xmlMarshal = null;
}
this.consumes = consumes;
this.produces = produces;
this.bindingMode = bindingMode;
this.skipBindingOnErrorCode = skipBindingOnErrorCode;
this.enableCORS = enableCORS;
this.corsHeaders = corsHeaders;
}
@Override
public void process(Exchange exchange) throws Exception {
AsyncProcessorHelper.process(this, exchange);
}
@Override
public boolean process(Exchange exchange, final AsyncCallback callback) {
if (enableCORS) {
exchange.addOnCompletion(new RestBindingCORSOnCompletion(corsHeaders));
}
boolean isXml = false;
boolean isJson = false;
String contentType = ExchangeHelper.getContentType(exchange);
if (contentType != null) {
isXml = contentType.toLowerCase(Locale.ENGLISH).contains("xml");
isJson = contentType.toLowerCase(Locale.ENGLISH).contains("json");
}
// if content type could not tell us if it was json or xml, then fallback to if the binding was configured with
// that information in the consumes
if (!isXml && !isJson) {
isXml = consumes != null && consumes.toLowerCase(Locale.ENGLISH).contains("xml");
isJson = consumes != null && consumes.toLowerCase(Locale.ENGLISH).contains("json");
}
// only allow xml/json if the binding mode allows that
isXml &= bindingMode.equals("auto") || bindingMode.contains("xml");
isJson &= bindingMode.equals("auto") || bindingMode.contains("json");
// if we do not yet know if its xml or json, then use the binding mode to know the mode
if (!isJson && !isXml) {
isXml = bindingMode.equals("auto") || bindingMode.contains("xml");
isJson = bindingMode.equals("auto") || bindingMode.contains("json");
}
String accept = exchange.getIn().getHeader("Accept", String.class);
String body = null;
if (exchange.getIn().getBody() != null) {
// okay we have a binding mode, so need to check for empty body as that can cause the marshaller to fail
// as they assume a non-empty body
if (isXml || isJson) {
// we have binding enabled, so we need to know if there body is empty or not\
// so force reading the body as a String which we can work with
body = MessageHelper.extractBodyAsString(exchange.getIn());
if (body != null) {
exchange.getIn().setBody(body);
if (isXml && isJson) {
// we have still not determined between xml or json, so check the body if its xml based or not
isXml = body.startsWith("<");
isJson = !isXml;
}
}
}
}
// favor json over xml
if (isJson && jsonUnmarshal != null) {
// add reverse operation
exchange.addOnCompletion(new RestBindingMarshalOnCompletion(exchange.getFromRouteId(), jsonMarshal, xmlMarshal, false, accept));
if (ObjectHelper.isNotEmpty(body)) {
return jsonUnmarshal.process(exchange, callback);
} else {
callback.done(true);
return true;
}
} else if (isXml && xmlUnmarshal != null) {
// add reverse operation
exchange.addOnCompletion(new RestBindingMarshalOnCompletion(exchange.getFromRouteId(), jsonMarshal, xmlMarshal, true, accept));
if (ObjectHelper.isNotEmpty(body)) {
return xmlUnmarshal.process(exchange, callback);
} else {
callback.done(true);
return true;
}
}
// we could not bind
if (bindingMode == null || "off".equals(bindingMode) || bindingMode.equals("auto")) {
// okay for auto we do not mind if we could not bind
exchange.addOnCompletion(new RestBindingMarshalOnCompletion(exchange.getFromRouteId(), jsonMarshal, xmlMarshal, false, accept));
callback.done(true);
return true;
} else {
if (bindingMode.contains("xml")) {
exchange.setException(new BindingException("Cannot bind to xml as message body is not xml compatible", exchange));
} else {
exchange.setException(new BindingException("Cannot bind to json as message body is not json compatible", exchange));
}
callback.done(true);
return true;
}
}
@Override
public String toString() {
return "RestBindingProcessor";
}
@Override
protected void doStart() throws Exception {
// inject CamelContext before starting
if (jsonMarshal instanceof CamelContextAware) {
((CamelContextAware) jsonMarshal).setCamelContext(camelContext);
}
if (jsonUnmarshal instanceof CamelContextAware) {
((CamelContextAware) jsonUnmarshal).setCamelContext(camelContext);
}
if (xmlMarshal instanceof CamelContextAware) {
((CamelContextAware) xmlMarshal).setCamelContext(camelContext);
}
if (xmlUnmarshal instanceof CamelContextAware) {
((CamelContextAware) xmlUnmarshal).setCamelContext(camelContext);
}
ServiceHelper.startServices(jsonMarshal, jsonUnmarshal, xmlMarshal, xmlUnmarshal);
}
@Override
protected void doStop() throws Exception {
ServiceHelper.stopServices(jsonMarshal, jsonUnmarshal, xmlMarshal, xmlUnmarshal);
}
/**
* An {@link org.apache.camel.spi.Synchronization} that does the reverse operation
* of marshalling from POJO to json/xml
*/
private final class RestBindingMarshalOnCompletion extends SynchronizationAdapter {
private final AsyncProcessor jsonMarshal;
private final AsyncProcessor xmlMarshal;
private final String routeId;
private boolean wasXml;
private String accept;
private RestBindingMarshalOnCompletion(String routeId, AsyncProcessor jsonMarshal, AsyncProcessor xmlMarshal, boolean wasXml, String accept) {
this.routeId = routeId;
this.jsonMarshal = jsonMarshal;
this.xmlMarshal = xmlMarshal;
this.wasXml = wasXml;
this.accept = accept;
}
@Override
public void onAfterRoute(Route route, Exchange exchange) {
// we use the onAfterRoute callback, to ensure the data has been marshalled before
// the consumer writes the response back
// only trigger when it was the 1st route that was done
if (!routeId.equals(route.getId())) {
return;
}
// only marshal if there was no exception
if (exchange.getException() != null) {
return;
}
if (skipBindingOnErrorCode) {
Integer code = exchange.hasOut() ? exchange.getOut().getHeader(Exchange.HTTP_RESPONSE_CODE, Integer.class) : exchange.getIn().getHeader(Exchange.HTTP_RESPONSE_CODE, Integer.class);
// if there is a custom http error code then skip binding
if (code != null && code >= 300) {
return;
}
}
boolean isXml = false;
boolean isJson = false;
// accept takes precedence
if (accept != null) {
isXml = accept.toLowerCase(Locale.ENGLISH).contains("xml");
isJson = accept.toLowerCase(Locale.ENGLISH).contains("json");
}
// fallback to content type if still undecided
if (!isXml && !isJson) {
String contentType = ExchangeHelper.getContentType(exchange);
if (contentType != null) {
isXml = contentType.toLowerCase(Locale.ENGLISH).contains("xml");
isJson = contentType.toLowerCase(Locale.ENGLISH).contains("json");
}
}
// if content type could not tell us if it was json or xml, then fallback to if the binding was configured with
// that information in the consumes
if (!isXml && !isJson) {
isXml = produces != null && produces.toLowerCase(Locale.ENGLISH).contains("xml");
isJson = produces != null && produces.toLowerCase(Locale.ENGLISH).contains("json");
}
// only allow xml/json if the binding mode allows that (when off we still want to know if its xml or json)
if (bindingMode != null) {
isXml &= bindingMode.equals("off") || bindingMode.equals("auto") || bindingMode.contains("xml");
isJson &= bindingMode.equals("off") || bindingMode.equals("auto") || bindingMode.contains("json");
// if we do not yet know if its xml or json, then use the binding mode to know the mode
if (!isJson && !isXml) {
isXml = bindingMode.equals("auto") || bindingMode.contains("xml");
isJson = bindingMode.equals("auto") || bindingMode.contains("json");
}
}
// in case we have not yet been able to determine if xml or json, then use the same as in the unmarshaller
if (isXml && isJson) {
isXml = wasXml;
isJson = !wasXml;
}
// need to prepare exchange first
ExchangeHelper.prepareOutToIn(exchange);
// ensure there is a content type header (even if binding is off)
ensureHeaderContentType(produces, isXml, isJson, exchange);
if (bindingMode == null || "off".equals(bindingMode)) {
// binding is off, so no message body binding
return;
}
// is there any marshaller at all
if (jsonMarshal == null && xmlMarshal == null) {
return;
}
// is the body empty
if ((exchange.hasOut() && exchange.getOut().getBody() == null) || (!exchange.hasOut() && exchange.getIn().getBody() == null)) {
return;
}
try {
// favor json over xml
if (isJson && jsonMarshal != null) {
jsonMarshal.process(exchange);
} else if (isXml && xmlMarshal != null) {
xmlMarshal.process(exchange);
} else {
// we could not bind
if (bindingMode.equals("auto")) {
// okay for auto we do not mind if we could not bind
} else {
if (bindingMode.contains("xml")) {
exchange.setException(new BindingException("Cannot bind to xml as message body is not xml compatible", exchange));
} else {
exchange.setException(new BindingException("Cannot bind to json as message body is not json compatible", exchange));
}
}
}
} catch (Throwable e) {
exchange.setException(e);
}
}
private void ensureHeaderContentType(String contentType, boolean isXml, boolean isJson, Exchange exchange) {
// favor given content type
if (contentType != null) {
String type = ExchangeHelper.getContentType(exchange);
if (type == null) {
exchange.getIn().setHeader(Exchange.CONTENT_TYPE, contentType);
}
}
// favor json over xml
if (isJson) {
// make sure there is a content-type with json
String type = ExchangeHelper.getContentType(exchange);
if (type == null) {
exchange.getIn().setHeader(Exchange.CONTENT_TYPE, "application/json");
}
} else if (isXml) {
// make sure there is a content-type with xml
String type = ExchangeHelper.getContentType(exchange);
if (type == null) {
exchange.getIn().setHeader(Exchange.CONTENT_TYPE, "application/xml");
}
}
}
@Override
public String toString() {
return "RestBindingMarshalOnCompletion";
}
}
private final class RestBindingCORSOnCompletion extends SynchronizationAdapter {
private final Map corsHeaders;
private RestBindingCORSOnCompletion(Map corsHeaders) {
this.corsHeaders = corsHeaders;
}
@Override
public void onAfterRoute(Route route, Exchange exchange) {
// add the CORS headers after routing, but before the consumer writes the response
Message msg = exchange.hasOut() ? exchange.getOut() : exchange.getIn();
// use default value if none has been configured
String allowOrigin = corsHeaders != null ? corsHeaders.get("Access-Control-Allow-Origin") : null;
if (allowOrigin == null) {
allowOrigin = RestConfiguration.CORS_ACCESS_CONTROL_ALLOW_ORIGIN;
}
String allowMethods = corsHeaders != null ? corsHeaders.get("Access-Control-Allow-Methods") : null;
if (allowMethods == null) {
allowMethods = RestConfiguration.CORS_ACCESS_CONTROL_ALLOW_METHODS;
}
String allowHeaders = corsHeaders != null ? corsHeaders.get("Access-Control-Allow-Headers") : null;
if (allowHeaders == null) {
allowHeaders = RestConfiguration.CORS_ACCESS_CONTROL_ALLOW_HEADERS;
}
String maxAge = corsHeaders != null ? corsHeaders.get("Access-Control-Max-Age") : null;
if (maxAge == null) {
maxAge = RestConfiguration.CORS_ACCESS_CONTROL_MAX_AGE;
}
msg.setHeader("Access-Control-Allow-Origin", allowOrigin);
msg.setHeader("Access-Control-Allow-Methods", allowMethods);
msg.setHeader("Access-Control-Allow-Headers", allowHeaders);
msg.setHeader("Access-Control-Max-Age", maxAge);
}
@Override
public String toString() {
return "RestBindingCORSOnCompletion";
}
}
}