Android Open Source - PkRSS Default Downloader

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Back to project page PkRSS.
License

The source code is released under:
Apache License
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Java Source Code

package com.pkmmte.pkrss.downloader;
//from w ww.j  a  v a  2  s  . com
import android.content.Context;
import android.net.Uri;
import android.net.http.HttpResponseCache;
import android.util.Log;
import com.pkmmte.pkrss.Request;
import com.pkmmte.pkrss.Utils;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * The Default Downloader object used for general purposes.
 * <p>
 * This Downloader class uses Android's built-in HttpUrlConnection for
 * networking. It is recommended to use the OkHttpDownloader instead as
 * it is more stable and potentially performs better.
 */
public class DefaultDownloader extends Downloader {
  // OkHttpClient & configuration
  private final File cacheDir;
  private final int cacheSize = 1024 * 1024;
  private final int cacheMaxAge = 2 * 60 * 60;
  private final long connectTimeout = 15000;
  private final long readTimeout = 45000;

  public DefaultDownloader(Context context)  {
    cacheDir = new File(context.getCacheDir(), "http");
    try {
      HttpResponseCache.install(cacheDir, cacheSize);
    }
    catch (IOException e) {
      Log.i(TAG, "HTTP response cache installation failed:" + e);
    }
  }

  @Override
  public boolean clearCache() {
    return Utils.deleteDir(cacheDir);
  }

  @Override
  public String execute(Request request) throws IllegalArgumentException, IOException {
    // Invalid URLs are a big no no
    if (request.url == null || request.url.isEmpty()) {
      throw new IllegalArgumentException("Invalid URL!");
    }

    // Start tracking download time
    long time = System.currentTimeMillis();

    // Empty response string placeholder
    String responseStr;

    // Handle cache
    int maxCacheAge = request.skipCache ? 0 : cacheMaxAge;

    // Build proper URL
    String requestUrl = toUrl(request);
    URL url = new URL(requestUrl);

    // Open a connection and configure timeouts/cache
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setRequestProperty("Cache-Control", "public, max-age=" + maxCacheAge);
    connection.setConnectTimeout((int) connectTimeout);
    connection.setReadTimeout((int) readTimeout);

    // Execute the request and log its data
    log("Making a request to " + requestUrl + (request.skipCache ? " [SKIP-CACHE]" : " [MAX-AGE " + maxCacheAge + "]"));
    connection.connect();

    // Read stream
    InputStream stream = null;
    try {
      // I really don't feel comfortable using InputStreams...
      stream = new BufferedInputStream(url.openStream(), 8192);
      int ch;
      StringBuffer builder = new StringBuffer();
      while ((ch = stream.read()) != -1) {
        builder.append((char) ch);
      }

      // Convert stream to a string
      responseStr = builder.toString();
      log(TAG, "Request download took " + (System.currentTimeMillis() - time) + "ms", Log.INFO);
    } catch (Exception e) {
      log("Error executing/reading http request!", Log.ERROR);
      e.printStackTrace();
      throw new IOException(e.getMessage());
    } finally {
      if (stream != null)
        stream.close();
      connection.disconnect();
    }

    return responseStr;
  }

  @Override
  public String toSafeUrl(Request request) {
    // Copy base url
    String url = request.url;

    if (request.individual) {
      // Append feed URL if individual article
      url += "feed/?withoutcomments=1";
    }
    else if (request.search != null) {
      // Append search query if available and not individual
      url += "?s=" + Uri.encode(request.search);
    }

    // Return safe url
    return url;
  }

  @Override
  public String toUrl(Request request) {
    // Copy base url
    String url = request.url;

    if (request.individual) {
      // Handle individual urls differently
      url += "feed/?withoutcomments=1";
    }
    else {
      if (request.search != null)
        url += "?s=" + Uri.encode(request.search);
      if (request.page > 1)
        url += (request.search == null ? "?paged=" : "&paged=") + String.valueOf(request.page);
    }

    // Return safe url
    return url;
  }
}
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