Cookie

起源

• 网景公司当时一名员工Lou Montulli，在1994年将“cookies”的概念应用于网络通信，用来解决用户网上购物的购物车历史记录，目前所有浏览器都支持cookies。

cookie是什么？

由于http是无状态的协议，一旦客户端和服务器的数据交换完毕，就会断开连接，再次请求，会重新连接，这就说明服务器单从网络连接上是没有办法知道用户身份的。怎么办呢？那就给每次新的用户请求时，给它颁发一个身份证（独一无二）吧，下次访问，必须带上身份证，这样服务器就会知道是谁来访问了，针对不同用户，做出不同的响应。，这就是Cookie的原理。
其实cookie是一个很小的文本文件，是浏览器储存在用户的机器上的。Cookie是纯文本，没有可执行代码。储存一些服务器需要的信息，每次请求站点，会发送相应的cookie，这些cookie可以用来辨别用户身份信息等作用。

作用：

• 会话管理，登陆状态，购物车
• 个性化：用户偏好
• 会话管理，登陆状态，购物车

比如说IC卡

• 银行卡里存身份信息，公交卡存的信息，每次上对应的机器上就能从IC卡读取到信息认证方便操作

Android对cookie的持久化演示

cookie对象

public class CookieBean {
private String  host;
private String  name;
private String  value;
private long    expiresAt;
private String  domain;
private String  path;
private boolean secure;
private boolean httpOnly;}

cookie管理器

public class CookiesManager implements CookieJar {
private final PersistentCookieStore cookieStore = new PersistentCookieStore(GameCenterApp.getApplication());
@Override
public void saveFromResponse(@NonNull HttpUrl url, @NonNull List<Cookie> cookies) {
    if(cookies.size() > 0) {
        for(Cookie item : cookies) {
            cookieStore.add(url, item);
        }
    }
}
@NonNull
@Override
public List<Cookie> loadForRequest(@NonNull HttpUrl url) {
    return cookieStore.get(url);
}

//清除所有cookie
public void removeAllCookie() {
    cookieStore.removeAll();
}}

持久化处理cookie

public class PersistentCookieStore {
private static final String LOG_TAG  = "PersistentCookieStore";
private static final String COOKIE_PREFS = "Cookies_Prefs_Game_Center";
private finalMap<String, ConcurrentHashMap<String, Cookie>> cookies;
private finalSharedPreferences  cookiePrefs;
PersistentCookieStore(Context context) {
cookiePrefs = context.getSharedPreferences(COOKIE_PREFS, Context.MODE_PRIVATE);
cookies = new LinkedHashMap<>();
    //将持久化的cookies缓存到内存中 即map cookies
    Map<String, ?> prefsMap = cookiePrefs.getAll();
    for(Map.Entry<String, ?> entry : prefsMap.entrySet()) {
        String[] cookieNames = TextUtils.split((String) entry.getValue(), ",");
        for(String name : cookieNames) {
            String encodedCookie = cookiePrefs.getString(name, null);
            if(encodedCookie != null) {
                Cookie cookie = decodeCookie(encodedCookie);
                if(cookie != null) {
                    String host = entry.getKey();
                    refreshUserLocalCookie(host, cookie);
                    LogUtil.d(LOG_TAG, "init: host="+host+", cookie="+cookie.toString());
                    if(!cookies.containsKey(host)) {
                        cookies.put(host, new ConcurrentHashMap<>());
                    }
                    ConcurrentHashMap<String, Cookie> map = cookies.get(host);
                    if(map != null) map.put(name, cookie);
                }
            }
        }
    }
}

private String getCookieToken(Cookie cookie) {
    return cookie.name()+"@"+cookie.domain();
}

public void add(HttpUrl url, Cookie cookie) {
    if(url == null || cookie == null) return;
    String host = url.host();
    LogUtil.d(LOG_TAG, "add: host="+host+", cookie="+cookie.toString());
    String name = getCookieToken(cookie);
    //将cookies缓存到内存中 如果缓存过期 就重置此cookie
    if(!cookie.persistent()) {
        if(!cookies.containsKey(host)) {
            cookies.put(host, new ConcurrentHashMap<>());
        }
        ConcurrentHashMap<String, Cookie> map = cookies.get(host);
        if(map != null) map.put(name, cookie);
    } else {
        if(cookies.containsKey(host)) {
            ConcurrentHashMap<String, Cookie> map = cookies.get(host);
            if(map != null) map.remove(name);
        }
    }
    //讲cookies持久化到本地
    SharedPreferences.Editor          prefsWriter = cookiePrefs.edit();
    ConcurrentHashMap<String, Cookie> map         = cookies.get(host);
    if(map != null) {
        refreshUserLocalCookie(host, cookie);
        prefsWriter.putString(host, TextUtils.join(",", map.keySet()));
        prefsWriter.putString(name, encodeCookie(new SerializableOkHttpCookies(cookie)));
        prefsWriter.commit();
    }
    String value = cookie.name()+"="+cookie.value();
    CookieManager.getInstance().setCookie(url.toString(), value);
}

public List<Cookie> get(HttpUrl url) {
    ArrayList<Cookie> ret = new ArrayList<>();
    if(url != null) {
        String host = url.host();
        if(cookies.containsKey(host)) {
            ConcurrentHashMap<String, Cookie> map = cookies.get(host);
            if(map != null) {
                ret.addAll(map.values());
            }
        }
    }
    return ret;
}

void removeAll() {
    cookiePrefs.edit().clear().commit();
    cookies.clear();
    CookieManager.getInstance().removeAllCookie();
}

public boolean remove(HttpUrl url, Cookie cookie) {
    if(url == null || cookie == null) return false;
    String host = url.host();
    LogUtil.d(LOG_TAG, "remove: host="+host+", cookie="+cookie.toString());
    String name = getCookieToken(cookie);
    refreshUserLocalCookie(host, cookie);
    if(cookies.containsKey(host) && cookies.get(host).containsKey(name)) {
        cookies.get(host).remove(name);

        SharedPreferences.Editor prefsWriter = cookiePrefs.edit();
        if(cookiePrefs.contains(name)) {
            prefsWriter.remove(name);
        }
        prefsWriter.putString(host, TextUtils.join(",", cookies.get(host).keySet()));
        prefsWriter.apply();

        return true;
    } else {
        return false;
    }
}

public List<Cookie> getCookies() {
    ArrayList<Cookie> ret = new ArrayList<>();
    for(String key : cookies.keySet())
        ret.addAll(cookies.get(key).values());
    return ret;
}

//同步cookie
private void refreshUserLocalCookie(String host, Cookie cookie) {
    if("USER_SESSIONID".equalsIgnoreCase(cookie.name())) {
        CookieBean cookieBean = new CookieBean();
        cookieBean.setHost(host);
        cookieBean.setName(cookie.name());
        cookieBean.setValue(cookie.value());
        cookieBean.setExpiresAt(cookie.expiresAt());
        cookieBean.setDomain(cookie.domain());
        cookieBean.setPath(cookie.path());
        cookieBean.setSecure(cookie.secure());
        cookieBean.setHttpOnly(cookie.httpOnly());
        UserInfoManager.refreshCookie(cookieBean);
    }
}

/**
 * cookies 序列化成 string
 *
 * @param cookie 要序列化的cookie
 *
 * @return 序列化之后的string
 */
private String encodeCookie(SerializableOkHttpCookies 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());
}

/**
 * 将字符串反序列化成cookies
 *
 * @param cookieString cookies string
 *
 * @return cookie object
 */
private Cookie decodeCookie(String cookieString) {
    byte[]               bytes                = hexStringToByteArray(cookieString);
    ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes);
    Cookie               cookie               = null;
    try {
        ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream);
        cookie = ((SerializableOkHttpCookies) objectInputStream.readObject()).getCookies();
    } catch(IOException e) {
        Log.d(LOG_TAG, "IOException in decodeCookie", e);
    } catch(ClassNotFoundException e) {
        Log.d(LOG_TAG, "ClassNotFoundException in decodeCookie", e);
    }
    return cookie;
}

/**
 * 二进制数组转十六进制字符串
 *
 * @param bytes byte array to be converted
 *
 * @return string containing hex values
 */
private 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);
}

/**
 * 十六进制字符串转二进制数组
 *
 * @param hexString string of hex-encoded values
 *
 * @return decoded byte array
 */
private 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;
}

}
public class SerializableOkHttpCookies implements Serializable {
private transient final Cookie cookies;
private transient       Cookie clientCookies;

public SerializableOkHttpCookies(Cookie cookies) {
    this.cookies = cookies;
}

public Cookie getCookies() {
    Cookie bestCookies = cookies;
    if(clientCookies != null) {
        bestCookies = clientCookies;
    }
    return bestCookies;
}

private void writeObject(ObjectOutputStream out) throws IOException {
    out.writeObject(cookies.name());
    out.writeObject(cookies.value());
    out.writeLong(cookies.expiresAt());
    out.writeObject(cookies.domain());
    out.writeObject(cookies.path());
    out.writeBoolean(cookies.secure());
    out.writeBoolean(cookies.httpOnly());
    out.writeBoolean(cookies.hostOnly());
    out.writeBoolean(cookies.persistent());
}

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
    String         name       = (String) in.readObject();
    String         value      = (String) in.readObject();
    long           expiresAt  = in.readLong();
    String         domain     = (String) in.readObject();
    String         path       = (String) in.readObject();
    boolean        secure     = in.readBoolean();
    boolean        httpOnly   = in.readBoolean();
    boolean        hostOnly   = in.readBoolean();
    boolean        persistent = in.readBoolean();
    Cookie.Builder builder    = new Cookie.Builder();
    builder = builder.name(name);
    builder = builder.value(value);
    builder = builder.expiresAt(expiresAt);
    builder = hostOnly ? builder.hostOnlyDomain(domain) : builder.domain(domain);
    builder = builder.path(path);
    builder = secure ? builder.secure() : builder;
    builder = httpOnly ? builder.httpOnly() : builder;
    clientCookies = builder.build();
}
}