HttpHelper.java

/*
 *	This file is part of Transdroid Torrent Search 
 *	<http://code.google.com/p/transdroid-search/>
 *	
 *	Transdroid Torrent Search is free software: you can redistribute 
 *	it and/or modify it under the terms of the GNU Lesser General 
 *	Public License as published by the Free Software Foundation, 
 *	either version 3 of the License, or (at your option) any later 
 *	version.
 *	
 *	Transdroid Torrent Search 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 Lesser General Public License for more details.
 *	
 *	You should have received a copy of the GNU Lesser General Public 
 *	License along with Transdroid.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.transdroid.util;

import org.apache.http.Header;
import org.apache.http.HeaderElement;
import org.apache.http.HttpEntity;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.HttpResponse;
import org.apache.http.HttpResponseInterceptor;
import org.apache.http.client.HttpClient;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.entity.HttpEntityWrapper;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.HttpContext;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.zip.GZIPInputStream;

/**
 * Provides a set of general helper methods that can be used in web-based communication.
 * @author erickok
 */
public class HttpHelper {

	public static HttpClient buildDefaultSearchHttpClient(boolean ignoreSslIssues) {

		SchemeRegistry registry = new SchemeRegistry();
		registry.register(new Scheme("http", new PlainSocketFactory(), 80));
		registry.register(new Scheme("https", ignoreSslIssues ? new IgnoreTlsSniSocketFactory() : new TlsSniSocketFactory(), 443));

		HttpParams httpparams = new BasicHttpParams();
		HttpConnectionParams.setConnectionTimeout(httpparams, 8000);
		HttpConnectionParams.setSoTimeout(httpparams, 8000);
		DefaultHttpClient httpclient = new DefaultHttpClient(new ThreadSafeClientConnManager(httpparams, registry), httpparams);

		httpclient.addRequestInterceptor(HttpHelper.gzipRequestInterceptor);
		httpclient.addResponseInterceptor(HttpHelper.gzipResponseInterceptor);

		return httpclient;

	}

	/**
	 * HTTP request interceptor to allow for GZip-encoded data transfer
	 */
	public static HttpRequestInterceptor gzipRequestInterceptor = new HttpRequestInterceptor() {
		public void process(final HttpRequest request, final HttpContext context) throws HttpException, IOException {
			if (!request.containsHeader("Accept-Encoding")) {
				request.addHeader("Accept-Encoding", "gzip");
			}
		}
	};

	/**
	 * HTTP response interceptor that decodes GZipped data
	 */
	public static HttpResponseInterceptor gzipResponseInterceptor = new HttpResponseInterceptor() {
		public void process(final HttpResponse response, final HttpContext context) throws HttpException, IOException {
			HttpEntity entity = response.getEntity();
			Header ceheader = entity.getContentEncoding();
			if (ceheader != null) {
				HeaderElement[] codecs = ceheader.getElements();
				for (HeaderElement codec : codecs) {

					if (codec.getName().equalsIgnoreCase("gzip")) {
						response.setEntity(new GzipDecompressingEntity(response.getEntity()));
						return;
					}
				}
			}
		}

	};

	/**
	 * HTTP entity wrapper to decompress GZipped HTTP responses
	 */
	private static class GzipDecompressingEntity extends HttpEntityWrapper {

		public GzipDecompressingEntity(final HttpEntity entity) {
			super(entity);
		}

		@Override
		public InputStream getContent() throws IOException, IllegalStateException {

			// the wrapped entity's getContent() decides about repeatability
			InputStream wrappedin = wrappedEntity.getContent();

			return new GZIPInputStream(wrappedin);
		}

		@Override
		public long getContentLength() {
			// length of ungzipped content is not known
			return -1;
		}

	}

	/*
	 * To convert the InputStream to String we use the BufferedReader.readLine()
	 * method. We iterate until the BufferedReader return null which means
	 * there's no more data to read. Each line will appended to a StringBuilder
	 * and returned as String.
	 *
	 * Taken from http://senior.ceng.metu.edu.tr/2009/praeda/2009/01/11/a-simple-restful-client-at-android/
	 */
	public static String convertStreamToString(InputStream is, String encoding) throws UnsupportedEncodingException {
		InputStreamReader isr;
		if (encoding != null) {
			isr = new InputStreamReader(is, encoding);
		} else {
			isr = new InputStreamReader(is);
		}
		BufferedReader reader = new BufferedReader(isr);
		StringBuilder sb = new StringBuilder();

		String line;
		try {
			while ((line = reader.readLine()) != null) {
				sb.append(line).append("\n");
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				is.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return sb.toString();
	}

	public static String convertStreamToString(InputStream is) {
		try {
			return convertStreamToString(is, null);
		} catch (UnsupportedEncodingException e) {
			// Since this is going to use the default encoding, it is never going to crash on an UnsupportedEncodingException
			e.printStackTrace();
			return null;
		}
	}

}