net.atoom.android.tt2.HttpConnection.java Source code

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Here is the source code for net.atoom.android.tt2.HttpConnection.java

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/**
 *    Copyright 2009 Bram de Kruijff <bdekruijff [at] gmail [dot] 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 net.atoom.android.tt2;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

import net.atoom.android.tt2.util.LogBridge;

import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.impl.client.DefaultHttpClient;

public final class HttpConnection {

    private static final int HTTP_OK = 200;
    private static final String ETAG_HEADER = "ETag";
    private static final String DEFAULT_ENCODING = "Cp1252";

    private final DefaultHttpClient myHttpClient = new DefaultHttpClient();

    public HttpConnection() {
    }

    public synchronized PageEntity loadPage(final String pageUrl) {
        HttpGet httpUriRequest = new HttpGet(pageUrl);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            HttpResponse httpResponse = myHttpClient.execute(httpUriRequest);

            // this happens...
            if (httpResponse.getStatusLine().getStatusCode() != HTTP_OK) {
                if (LogBridge.isLoggable())
                    LogBridge.w("Invalid statuscode for: " + pageUrl);
                return null;
            }
            HttpEntity httpEntity = httpResponse.getEntity();
            httpEntity.writeTo(baos);
            String eTag = httpResponse.getFirstHeader(ETAG_HEADER).getValue();
            String htmlData = baos.toString(DEFAULT_ENCODING);

            // this happens too..
            if (htmlData.equals("")) {
                if (LogBridge.isLoggable())
                    LogBridge.w("Empty responsebody for: " + pageUrl);
                return null;
            }

            return new PageEntity(pageUrl, htmlData, eTag);
        } catch (ClientProtocolException e) {
            if (LogBridge.isLoggable())
                LogBridge.w("Failed to load page: " + e.getMessage());
        } catch (IOException e) {
            if (LogBridge.isLoggable())
                LogBridge.w("Failed to load page: " + e.getMessage());
        }
        return null;
    }

    public synchronized boolean isPageModified(final String pageUrl, final String eTag) {
        HttpHead httpUriRequest = new HttpHead(pageUrl);
        try {
            HttpResponse httpResponse = myHttpClient.execute(httpUriRequest);
            if (httpResponse.getStatusLine().getStatusCode() != HTTP_OK) {
                if (LogBridge.isLoggable())
                    LogBridge.w("Invalid statuscode for: " + pageUrl);
                return false;
            }
            Header eTagHeader = httpResponse.getFirstHeader(ETAG_HEADER);
            if (eTagHeader != null && eTagHeader.getValue().equals(eTag)) {
                if (LogBridge.isLoggable())
                    LogBridge.i("Page not modified: " + pageUrl + " (" + eTag + ")");
                return true;
            }
        } catch (ClientProtocolException e) {
            if (LogBridge.isLoggable())
                LogBridge.w("Failed to check page: " + e.getMessage());
        } catch (IOException e) {
            if (LogBridge.isLoggable())
                LogBridge.w("Failed to check page: " + e.getMessage());
        }
        if (LogBridge.isLoggable())
            LogBridge.i("Page is modified: " + pageUrl + "/ (" + eTag + ")");
        return false;
    }
}