RpcServiceEngine.java

/*
 * � Copyright IBM Corp. 2010
 * 
 * Licensed 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 com.ibm.domino.services.rpc;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.ibm.commons.util.StringUtil;
import com.ibm.commons.util.io.json.JsonFactory;
import com.ibm.commons.util.io.json.JsonGenerator;
import com.ibm.commons.util.io.json.JsonParser;
import com.ibm.domino.services.HttpServiceEngine;
import com.ibm.domino.services.ServiceException;
import com.ibm.jscript.std.ObjectObject;

import static com.ibm.domino.services.rest.RestServiceConstants.*;
import static com.ibm.domino.services.HttpServiceConstants.*;

/**
 * RPC Service Engine.
 */
public abstract class RpcServiceEngine extends HttpServiceEngine {
    
    public RpcServiceEngine(HttpServletRequest httpRequest, HttpServletResponse httpResponse) {
        super(httpRequest,httpResponse);
    }
    
    @Override
    public void renderService() throws ServiceException {
        JsonFactory factory = getJsonFactory();

        // Parse the body 
        try {
            InputStream is = getHttpRequest().getInputStream();  
            Object o = (ObjectObject)JsonParser.fromJson(factory, new InputStreamReader(is,ENCODING_UTF8));
            
            int id = (int)factory.getNumber(factory.getProperty(o, JSON_FACTORY_PROPERTY_ID));
            String methodName = factory.getString((factory.getProperty(o, JSON_FACTORY_PROPERTY_METHOD)));
            Object params = factory.getProperty(o, JSON_FACTORY_PROPERTY_PARAMS);

            Object res = factory.createObject(null, null);
            factory.setProperty(res, JSON_FACTORY_PROPERTY_ID, factory.createNumber(id));
    
            RpcMethod method = findMethod(methodName);
    
            if(method!=null) {
                Object result = method.invoke(getHttpRequest(), id, params);
                factory.setProperty(res, JSON_FACTORY_PROPERTY_RESULT, result);
            } else {
                factory.setProperty(res, JSON_FACTORY_PROPERTY_ERROR, factory.createString(StringUtil.format("Unknown method {0}", methodName))); // $NLX-RpcServiceEngine.Unknownmethod0-1$
            }
            
            getHttpResponse().setContentType(CONTENTTYPE_TEXT_JSON);
            getHttpResponse().setCharacterEncoding(ENCODING_UTF8);
            
            OutputStream os = getOutputStream();
            Writer w = new OutputStreamWriter(os,ENCODING_UTF8);
            JsonGenerator.toJson(factory, w, res, false); // last is "compact"
            w.flush();
            
        } catch(Exception ex) {
            throw new ServiceException(ex,""); // $NON-NLS-1$
        }
    }
    
    protected abstract JsonFactory getJsonFactory() throws ServiceException;
    protected abstract RpcMethod findMethod(String methodName) throws ServiceException; 
}