de.dan_nrw.web.WebClient.java Source code

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Here is the source code for de.dan_nrw.web.WebClient.java

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/* 
 * de.dan_nrw.web
 * 
 * Copyright (C) 2010, Daniel Czerwonk <d.czerwonk@googlemail.com>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package de.dan_nrw.web;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;

import org.apache.http.ProtocolException;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.Credentials;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import de.dan_nrw.web.UserAgent;

/**
 * @author Daniel Czerwonk
 */
public class WebClient {

    private final UserAgent userAgent;
    private Credentials credentials;

    /**
     * Creates a new instance of WebClient
     * (uses Firefox 3 user agent signature as default)
     */
    public WebClient() {
        this.userAgent = UserAgent.FIREFOX_3;
    }

    /**
     * Creates a new instance of WebClient
     * @param userAgent
     */
    public WebClient(UserAgent userAgent) {
        super();

        this.userAgent = userAgent;
    }

    /**
     * Gets the credentials used for authentification
     * @return
     */
    public Credentials getCredentials() {
        return this.credentials;
    }

    /**
     * Sets the credentials used for authentification
     * @param credentials
     */
    public void setCredentials(Credentials credentials) {
        this.credentials = credentials;
    }

    /**
     * Sends a http request and returns repsonse as string
     * @param uri URI to use
     * @return
     * @throws IOException if response handling fails
     * @throws ProtocolException if request returns an error
     */
    public String getResponseString(URI uri) throws IOException, ProtocolException {
        return this.sendRequest(uri, new StringResponseHandler());
    }

    /**
     * Sends a http request and stores its response stream in specified file
     * @param uri URI to use
     * @param targetFile File to store data downloaded
     * @throws IOException if response handling fails
     * @throws ProtocolException if request returns an error
     */
    public void downloadFile(URI uri, File targetFile) throws IOException, ProtocolException {
        this.sendRequest(uri, new FileDownloadResponseHandler(targetFile));
    }

    /**
     * Sends a http request and returns its reponse stream
     * @param uri URI to use
     * @return Stream provided by response
     * @throws IOException if response handling fails
     * @throws ProtocolException if request returns an error
     */
    public InputStream getResponseStream(URI uri) throws IOException, ProtocolException {
        return this.sendRequest(uri, new StreamResponseHandler());
    }

    /**
     * Sends a http request and handles response using specified ResponseHandler
     * @param <T> Type of return
     * @param uri URI to use
     * @param responseHandler Response handled used for handling response
     * @return
     * @throws IOException if response handling fails
     * @throws ProtocolException if request returns an error
     */
    public <T> T sendRequest(URI uri, ResponseHandler<T> responseHandler) throws IOException, ProtocolException {
        HttpGet request = new HttpGet(uri);
        request.addHeader("User-agent", this.userAgent.getHeaderValue());

        DefaultHttpClient client = new DefaultHttpClient();

        if (this.credentials != null) {
            client.getCredentialsProvider().setCredentials(AuthScope.ANY, this.credentials);
        }

        return client.execute(request, responseHandler);
    }
}