org.codebistro.jsonrpc.HTTPSession.java Source code

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Here is the source code for org.codebistro.jsonrpc.HTTPSession.java

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/*
 * JSON-RPC-Client, a Java client extension to JSON-RPC-Java
 *
 * (C) Copyright CodeBistro 2007, Sasha Ovsankin <sasha@codebistro.com>
 *
 * 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 org.codebistro.jsonrpc;

import java.io.IOException;
import java.net.URI;
import java.text.ParseException;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpState;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.RequestEntity;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codebistro.jsonrpc.TransportRegistry.SessionFactory;
import org.json.JSONObject;
import org.json.JSONTokener;

public class HTTPSession implements Session {
    private static Log log = LogFactory.getLog(HTTPSession.class);

    protected HttpClient client;
    protected HttpState state;
    protected URI uri;

    public HTTPSession(URI uri) {
        this.uri = uri;
    }

    /** 
     * An option to set state from the outside.
     * for example, to provide existing session parameters.
     */
    public void setState(HttpState state) {
        this.state = state;
    }

    public JSONObject sendAndReceive(JSONObject message) {
        if (log.isDebugEnabled())
            log.debug("Sending: " + message.toString(2));
        PostMethod postMethod = new PostMethod(uri.toString());
        postMethod.setRequestHeader("Content-Type", "text/plain");

        RequestEntity requestEntity = new StringRequestEntity(message.toString());
        postMethod.setRequestEntity(requestEntity);
        try {
            http().executeMethod(null, postMethod, state);
            int statusCode = postMethod.getStatusCode();
            if (statusCode != HttpStatus.SC_OK)
                throw new ClientError(
                        "HTTP Status - " + HttpStatus.getStatusText(statusCode) + " (" + statusCode + ")");
            JSONTokener tokener = new JSONTokener(postMethod.getResponseBodyAsString());
            Object rawResponseMessage = tokener.nextValue();
            JSONObject responseMessage = (JSONObject) rawResponseMessage;
            if (responseMessage == null)
                throw new ClientError("Invalid response type - " + rawResponseMessage.getClass());
            return responseMessage;
        } catch (ParseException e) {
            throw new ClientError(e);
        } catch (HttpException e) {
            throw new ClientError(e);
        } catch (IOException e) {
            throw new ClientError(e);
        }
    }

    HttpClient http() {
        if (client == null) {
            client = new HttpClient();
            if (state == null)
                state = new HttpState();
            client.setState(state);
        }
        return client;
    }

    public void close() {
        state.clear();
        state = null;
    }

    static class Factory implements SessionFactory {
        public Session newSession(URI uri) {
            return new HTTPSession(uri);
        }
    }

    /** 
     * Register this transport in 'registry'
     */
    public static void register(TransportRegistry registry) {
        registry.registerTransport("http", new Factory());
    }
}