PersistentCookieStore.java

/*
    Android Asynchronous Http Client
    Copyright (c) 2011 James Smith <james@loopj.com>
    http://loopj.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 com.smartandroid.sa.loopj;

import android.content.Context;
import android.content.SharedPreferences;
import android.text.TextUtils;
import android.util.Log;

import org.apache.http.client.CookieStore;
import org.apache.http.cookie.Cookie;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

import java.io.IOException;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.ConcurrentHashMap;

/**
 * A persistent cookie store which implements the Apache HttpClient
 * {@link CookieStore} interface. Cookies are stored and will persist on the
 * user's device between application sessions since they are serialized and
 * stored in {@link SharedPreferences}.
 * <p>
 *  
 * </p>
 * Instances of this class are designed to be used with
 * {@link AsyncHttpClient#setCookieStore}, but can also be used with a regular
 * old apache HttpClient/HttpContext if you prefer.
 */
public class PersistentCookieStore implements CookieStore {
	private static final String LOG_TAG = "PersistentCookieStore";
	private static final String COOKIE_PREFS = "CookiePrefsFile";
	private static final String COOKIE_NAME_STORE = "names";
	private static final String COOKIE_NAME_PREFIX = "cookie_";
	private boolean omitNonPersistentCookies = false;

	private final ConcurrentHashMap<String, Cookie> cookies;
	private final SharedPreferences cookiePrefs;

	/**
	 * Construct a persistent cookie store.
	 * 
	 * @param context
	 *            Context to attach cookie store to
	 */
	public PersistentCookieStore(Context context) {
		cookiePrefs = context.getSharedPreferences(COOKIE_PREFS, 0);
		cookies = new ConcurrentHashMap<String, Cookie>();

		// Load any previously stored cookies into the store
		String storedCookieNames = cookiePrefs.getString(COOKIE_NAME_STORE,
				null);
		if (storedCookieNames != null) {
			String[] cookieNames = TextUtils.split(storedCookieNames, ",");
			for (String name : cookieNames) {
				String encodedCookie = cookiePrefs.getString(COOKIE_NAME_PREFIX
						+ name, null);
				if (encodedCookie != null) {
					Cookie decodedCookie = decodeCookie(encodedCookie);
					if (decodedCookie != null) {
						cookies.put(name, decodedCookie);
					}
				}
			}

			// Clear out expired cookies
			clearExpired(new Date());
		}
	}

	@Override
	public void addCookie(Cookie cookie) {
		if (omitNonPersistentCookies && !cookie.isPersistent())
			return;
		String name = cookie.getName() + cookie.getDomain();

		// Save cookie into local store, or remove if expired
		if (!cookie.isExpired(new Date())) {
			cookies.put(name, cookie);
		} else {
			cookies.remove(name);
		}

		// Save cookie into persistent store
		SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
		prefsWriter.putString(COOKIE_NAME_STORE,
				TextUtils.join(",", cookies.keySet()));
		prefsWriter.putString(COOKIE_NAME_PREFIX + name,
				encodeCookie(new SerializableCookie(cookie)));
		prefsWriter.commit();
	}

	@Override
	public void clear() {
		// Clear cookies from persistent store
		SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
		for (String name : cookies.keySet()) {
			prefsWriter.remove(COOKIE_NAME_PREFIX + name);
		}
		prefsWriter.remove(COOKIE_NAME_STORE);
		prefsWriter.commit();

		// Clear cookies from local store
		cookies.clear();
	}

	@Override
	public boolean clearExpired(Date date) {
		boolean clearedAny = false;
		SharedPreferences.Editor prefsWriter = cookiePrefs.edit();

		for (ConcurrentHashMap.Entry<String, Cookie> entry : cookies.entrySet()) {
			String name = entry.getKey();
			Cookie cookie = entry.getValue();
			if (cookie.isExpired(date)) {
				// Clear cookies from local store
				cookies.remove(name);

				// Clear cookies from persistent store
				prefsWriter.remove(COOKIE_NAME_PREFIX + name);

				// We've cleared at least one
				clearedAny = true;
			}
		}

		// Update names in persistent store
		if (clearedAny) {
			prefsWriter.putString(COOKIE_NAME_STORE,
					TextUtils.join(",", cookies.keySet()));
		}
		prefsWriter.commit();

		return clearedAny;
	}

	@Override
	public List<Cookie> getCookies() {
		return new ArrayList<Cookie>(cookies.values());
	}

	/**
	 * Will make PersistentCookieStore instance ignore Cookies, which are
	 * non-persistent by signature (`Cookie.isPersistent`)
	 * 
	 * @param omitNonPersistentCookies
	 *            true if non-persistent cookies should be omited
	 */
	public void setOmitNonPersistentCookies(boolean omitNonPersistentCookies) {
		this.omitNonPersistentCookies = omitNonPersistentCookies;
	}

	/**
	 * Non-standard helper method, to delete cookie
	 * 
	 * @param cookie
	 *            cookie to be removed
	 */
	public void deleteCookie(Cookie cookie) {
		String name = cookie.getName() + cookie.getDomain();
		cookies.remove(name);
		SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
		prefsWriter.remove(COOKIE_NAME_PREFIX + name);
		prefsWriter.commit();
	}

	/**
	 * Serializes Cookie object into String
	 * 
	 * @param cookie
	 *            cookie to be encoded, can be null
	 * @return cookie encoded as String
	 */
	protected String encodeCookie(SerializableCookie cookie) {
		if (cookie == null)
			return null;
		ByteArrayOutputStream os = new ByteArrayOutputStream();
		try {
			ObjectOutputStream outputStream = new ObjectOutputStream(os);
			outputStream.writeObject(cookie);
		} catch (IOException e) {
			Log.d(LOG_TAG, "IOException in encodeCookie", e);
			return null;
		}

		return byteArrayToHexString(os.toByteArray());
	}

	/**
	 * Returns cookie decoded from cookie string
	 * 
	 * @param cookieString
	 *            string of cookie as returned from http request
	 * @return decoded cookie or null if exception occured
	 */
	protected Cookie decodeCookie(String cookieString) {
		byte[] bytes = hexStringToByteArray(cookieString);
		ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(
				bytes);
		Cookie cookie = null;
		try {
			ObjectInputStream objectInputStream = new ObjectInputStream(
					byteArrayInputStream);
			cookie = ((SerializableCookie) objectInputStream.readObject())
					.getCookie();
		} catch (IOException e) {
			Log.d(LOG_TAG, "IOException in decodeCookie", e);
		} catch (ClassNotFoundException e) {
			Log.d(LOG_TAG, "ClassNotFoundException in decodeCookie", e);
		}

		return cookie;
	}

	/**
	 * Using some super basic byte array <-> hex conversions so we don't
	 * have to rely on any large Base64 libraries. Can be overridden if you
	 * like!
	 * 
	 * @param bytes
	 *            byte array to be converted
	 * @return string containing hex values
	 */
	protected String byteArrayToHexString(byte[] bytes) {
		StringBuilder sb = new StringBuilder(bytes.length * 2);
		for (byte element : bytes) {
			int v = element & 0xff;
			if (v < 16) {
				sb.append('0');
			}
			sb.append(Integer.toHexString(v));
		}
		return sb.toString().toUpperCase(Locale.US);
	}

	/**
	 * Converts hex values from strings to byte arra
	 * 
	 * @param hexString
	 *            string of hex-encoded values
	 * @return decoded byte array
	 */
	protected byte[] hexStringToByteArray(String hexString) {
		int len = hexString.length();
		byte[] data = new byte[len / 2];
		for (int i = 0; i < len; i += 2) {
			data[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character
					.digit(hexString.charAt(i + 1), 16));
		}
		return data;
	}
}