org.apache.shindig.gadgets.servlet.RpcServlet.java Source code

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Here is the source code for org.apache.shindig.gadgets.servlet.RpcServlet.java

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/*
 * 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.shindig.gadgets.servlet;

import com.google.common.base.Preconditions;
import org.apache.commons.io.IOUtils;
import org.apache.shindig.common.servlet.HttpUtil;
import org.apache.shindig.common.servlet.InjectedServlet;
import org.json.JSONException;
import org.json.JSONObject;

import com.google.inject.Inject;

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

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Handles RPC metadata requests.
 */
public class RpcServlet extends InjectedServlet {

    private static final long serialVersionUID = 1382573217773582182L;

    static final String GET_REQUEST_REQ_PARAM = "req";
    static final String GET_REQUEST_CALLBACK_PARAM = "callback";

    private static final Logger LOG = Logger.getLogger("org.apache.shindig.gadgets");

    private transient JsonRpcHandler jsonHandler;

    @Inject
    public void setJsonRpcHandler(JsonRpcHandler jsonHandler) {
        checkInitialized();
        this.jsonHandler = jsonHandler;
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        String reqValue;
        String callbackValue;

        try {
            HttpUtil.isJSONP(request);
            reqValue = validateParameterValue(request, GET_REQUEST_REQ_PARAM);
            callbackValue = validateParameterValue(request, GET_REQUEST_CALLBACK_PARAM);
        } catch (IllegalArgumentException e) {
            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            LOG.log(Level.INFO, e.getMessage(), e);
            return;
        }

        Result result = process(request, response, reqValue);
        response.getWriter()
                .write(result.isSuccess() ? callbackValue + '(' + result.getOutput() + ')' : result.getOutput());
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
        try {
            InputStreamReader is = new InputStreamReader(request.getInputStream(),
                    getRequestCharacterEncoding(request));
            String body = IOUtils.toString(is);
            Result result = process(request, response, body);
            response.getWriter().write(result.getOutput());
        } catch (UnsupportedEncodingException e) {
            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            LOG.log(Level.INFO, e.getMessage(), e);
            response.getWriter().write("Unsupported input character set");
        }
    }

    private String validateParameterValue(HttpServletRequest request, String parameter)
            throws IllegalArgumentException {
        String result = request.getParameter(parameter);
        Preconditions.checkArgument(result != null, "No parameter '%s' specified", parameter);
        return result;
    }

    private Result process(HttpServletRequest request, HttpServletResponse response, String body) {
        try {
            JSONObject req = new JSONObject(body);
            JSONObject resp = jsonHandler.process(req);
            response.setStatus(HttpServletResponse.SC_OK);
            response.setContentType("application/json; charset=utf-8");
            response.setHeader("Content-Disposition", "attachment;filename=rpc.txt");
            return new Result(resp.toString(), true);
        } catch (JSONException e) {
            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            return new Result("Malformed JSON request.", false);
        } catch (RpcException e) {
            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            LOG.log(Level.INFO, e.getMessage(), e);
            return new Result(e.getMessage(), false);
        }
    }

    private String getRequestCharacterEncoding(HttpServletRequest request) {
        String encoding = request.getCharacterEncoding();
        if (encoding == null) {
            encoding = "UTF-8";
        }
        return encoding;
    }

    private static class Result {
        private final String output;
        private final boolean success;

        public Result(String output, boolean success) {
            this.output = output;
            this.success = success;
        }

        public String getOutput() {
            return output;
        }

        public boolean isSuccess() {
            return success;
        }
    }
}