CHTGetOp.java

package edu.washington.cs.oneswarm.ui.gwt.server.community;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.List;
import java.util.logging.Logger;

import org.json.JSONArray;
import org.json.JSONTokener;
import org.json.JSONWriter;

import com.google.common.base.Preconditions;
import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;

import edu.washington.cs.oneswarm.f2f.dht.CHTCallback;
import edu.washington.cs.oneswarm.ui.gwt.rpc.CommunityRecord;

public class CHTGetOp extends CommunityServerOperation {

    private static Logger logger = Logger.getLogger(CHTGetOp.class.getName());

    private final List<CHTCallback> callbacks;
    private final List<byte[]> keys;

    public CHTGetOp(CommunityRecord server, List<byte[]> keys, List<CHTCallback> callbacks) {
        super(server);

        Preconditions.checkArgument(keys.size() == callbacks.size(),
                "Mismatch between keys and callbacks sizese.");

        this.keys = keys;
        this.callbacks = callbacks;
    }

    @Override
    void doOp() {
        Preconditions.checkState(mRecord.isAllowAddressResolution(),
                "Attempting CHTGet on server without perms: " + mRecord.getBaseURL());

        Preconditions.checkState(mRecord.getCht_path() != null,
                "Attempting CHTGet on server without a valid CHT path! " + mRecord.getBaseURL());

        String path = mRecord.getBaseURL();
        if (path.endsWith("/") == false) {
            path += "/";
        }
        path += mRecord.getCht_path() + "?get";
        try {
            URL url = new URL(path);
            HttpURLConnection conn = getConnection(url, "POST");

            // JSON array of key, value pairs.
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            OutputStreamWriter outputStreamWriter = new OutputStreamWriter(baos);
            JSONWriter writer = new JSONWriter(outputStreamWriter);

            writer.array();
            for (int i = 0; i < keys.size(); i++) {
                String encodedKey = Base64.encode(keys.get(i));
                writer.value(encodedKey);
            }
            writer.endArray();
            outputStreamWriter.flush();

            logger.finest(baos.toString() + "\n");

            conn.getOutputStream().write(
                    ("q=" + URLEncoder.encode(baos.toString(), "UTF-8")).getBytes());

            logger.finer("CHT get response code: " + conn.getResponseCode() + " / "
                    + conn.getResponseMessage());

            // Collect and parse the get responses
            ByteArrayOutputStream response = new ByteArrayOutputStream();
            readLimitedInto(conn, 1024 * 1024, response);

            JSONTokener toks = new JSONTokener(new InputStreamReader(new ByteArrayInputStream(
                    response.toByteArray())));
            JSONArray vals = (JSONArray) toks.nextValue();
            Preconditions.checkState(vals.length() == callbacks.size(),
                    "Server returned " + vals.length() + " values, but we have " + callbacks.size()
                            + " CHT get callbacks.");
            for (int i = 0; i < vals.length(); i++) {
                CHTCallback callback = callbacks.remove(0);
                callback.valueReceived(keys.get(i), Base64.decode(vals.getString(i)));
            }

        } catch (Exception e) {
            e.printStackTrace();
            logger.warning("Error during CHT get on server: " + mRecord.getBaseURL() + " / "
                    + e.toString());

            for (CHTCallback c : callbacks) {
                c.errorReceived(e);
            }
        }
    }
}