org.apache.droids.protocol.http.HttpProtocol.java Source code

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Here is the source code for org.apache.droids.protocol.http.HttpProtocol.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.droids.protocol.http;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

import org.apache.droids.api.ManagedContentEntity;
import org.apache.droids.api.Protocol;
import org.apache.droids.norobots.ContentLoader;
import org.apache.droids.norobots.NoRobotClient;
import org.apache.droids.norobots.NoRobotException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.HttpResponseException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.params.CoreProtocolPNames;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Protocol handler based on HttpClient 4.0.
 */
public class HttpProtocol implements Protocol {

    private static final Logger LOG = LoggerFactory.getLogger(HttpProtocol.class);

    private final HttpClient httpclient;
    private final ContentLoader contentLoader;

    private boolean forceAllow = false;
    private String userAgent = "Apache-Droids/1.1 (java 1.5)";

    public HttpProtocol(final HttpClient httpclient) {
        super();
        this.httpclient = httpclient;
        this.httpclient.getParams().setParameter(CoreProtocolPNames.USER_AGENT, userAgent);
        this.contentLoader = new HttpClientContentLoader(httpclient);
    }

    public HttpProtocol() {
        this(new DroidsHttpClient());
    }

    @Override
    public ManagedContentEntity load(URI uri) throws IOException {
        HttpGet httpget = new HttpGet(uri);
        HttpResponse response = httpclient.execute(httpget);
        StatusLine statusline = response.getStatusLine();
        if (statusline.getStatusCode() >= HttpStatus.SC_BAD_REQUEST) {
            httpget.abort();
            throw new HttpResponseException(statusline.getStatusCode(), statusline.getReasonPhrase());
        }
        HttpEntity entity = response.getEntity();
        if (entity == null) {
            // Should _almost_ never happen with HTTP GET requests.
            throw new ClientProtocolException("Empty entity");
        }
        long maxlen = httpclient.getParams().getLongParameter(DroidsHttpClient.MAX_BODY_LENGTH, 0);
        return new HttpContentEntity(entity, maxlen);
    }

    @Override
    public boolean isAllowed(URI uri) throws IOException {
        if (forceAllow) {
            return forceAllow;
        }

        URI baseURI;
        try {
            baseURI = new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), uri.getPort(), "/", null, null);
        } catch (URISyntaxException ex) {
            LOG.error("Unable to determine base URI for " + uri);
            return false;
        }

        NoRobotClient nrc = new NoRobotClient(contentLoader, userAgent);
        try {
            nrc.parse(baseURI);
        } catch (NoRobotException ex) {
            LOG.error("Failure parsing robots.txt: " + ex.getMessage());
            return false;
        }
        boolean test = nrc.isUrlAllowed(uri);
        if (LOG.isInfoEnabled()) {
            LOG.info(uri + " is " + (test ? "allowed" : "denied"));
        }
        return test;
    }

    public String getUserAgent() {
        return userAgent;
    }

    public void setUserAgent(String userAgent) {
        this.userAgent = userAgent;
        this.httpclient.getParams().setParameter(CoreProtocolPNames.USER_AGENT, userAgent);
    }

    /**
     * You can force that a site is allowed (ignoring the robots.txt). This should
     * only be used on server that you control and where you have the permission
     * to ignore the robots.txt.
     * 
     * @return <code>true</code> if you are rude and ignore robots.txt.
     *         <code>false</code> if you are playing nice.
     */
    public boolean isForceAllow() {
        return forceAllow;
    }

    /**
     * You can force that a site is allowed (ignoring the robot.txt). This should
     * only be used on server that you control and where you have the permission
     * to ignore the robots.txt.
     * 
     * @param forceAllow
     *                if you want to force an allow and ignore the robot.txt set
     *                to <code>true</code>. If you want to obey the rules and
     *                be polite set to <code>false</code>.
     */
    public void setForceAllow(boolean forceAllow) {
        this.forceAllow = forceAllow;
    }

    protected HttpClient getHttpClient() {
        return this.httpclient;
    }

}