Android 自动登录——持久化Cookie

96
Mitaer
2018.05.17 16:31* 字数 266

背景

在使用鸿洋大神的玩Android网站开放的api开发android app时,使用Retrofit请求登录api,需要保存Cookie以备其他需要登陆后才能操作的api使用。

自定义拦截器实现持久化Cookie

首先定义响应拦截器,该拦截器实现从response获取set-cookie字段的值,并将其保存在本地。

public class SaveCookiesInterceptor implements Interceptor {

    private static final String COOKIE_PREF = "cookies_prefs";
    private Context mContext;

    protected SaveCookiesInterceptor(Context context) {
        mContext = context;
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        Response response = chain.proceed(request);
        //set-cookie可能为多个
        if (!response.headers("set-cookie").isEmpty()) {
            List<String> cookies = response.headers("set-cookie");
            String cookie = encodeCookie(cookies);
            saveCookie(request.url().toString(), request.url().host(), cookie);
        }

        return response;
    }

    /**
     * 整合cookie为唯一字符串
     */
    private String encodeCookie(List<String> cookies) {
        StringBuilder sb = new StringBuilder();
        Set<String> set = new HashSet<>();
        for (String cookie : cookies) {
            String[] arr = cookie.split(";");
            for (String s : arr) {
                if (set.contains(s)) {
                    continue;
                }
                set.add(s);

            }
        }

        for (String cookie : set) {
            sb.append(cookie).append(";");
        }

        int last = sb.lastIndexOf(";");
        if (sb.length() - 1 == last) {
            sb.deleteCharAt(last);
        }

        return sb.toString();
    }

    /**
     * 保存cookie到本地,这里我们分别为该url和host设置相同的cookie,其中host可选
     * 这样能使得该cookie的应用范围更广
     */
    private void saveCookie(String url, String domain, String cookies) {
        SharedPreferences sp = mContext.getSharedPreferences(COOKIE_PREF, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();

        if (TextUtils.isEmpty(url)) {
            throw new NullPointerException("url is null.");
        } else {
            editor.putString(url, cookies);
        }

        if (!TextUtils.isEmpty(domain)) {
            editor.putString(domain, cookies);
        }
        editor.apply();
    }

    /**
     * 清除本地Cookie
     *
     * @param context Context
     */
    public static void clearCookie(Context context) {
        SharedPreferences sp = context.getSharedPreferences(COOKIE_PREF, Context.MODE_PRIVATE);
        sp.edit().clear().apply();
    }
}

然后定义请求拦截器,如果该请求存在cookie,则为其添加到Header的Cookie中。

public class AddCookiesInterceptor implements Interceptor {
    private static final String COOKIE_PREF = "cookies_prefs";
    private Context mContext;

    public AddCookiesInterceptor(Context context) {
        mContext = context;
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        Request.Builder builder = request.newBuilder();
        String cookie = getCookie(request.url().toString(), request.url().host());
        if (!TextUtils.isEmpty(cookie)) {
            builder.addHeader("Cookie", cookie);
        }

        return chain.proceed(builder.build());
    }

    private String getCookie(String url, String domain) {
        SharedPreferences sp = mContext.getSharedPreferences(COOKIE_PREF, Context.MODE_PRIVATE);
        if (!TextUtils.isEmpty(url) && sp.contains(url) && !TextUtils.isEmpty(sp.getString(url, ""))) {
            return sp.getString(url, "");
        }
        if (!TextUtils.isEmpty(domain) && sp.contains(domain) && !TextUtils.isEmpty(sp.getString(domain, ""))) {
            return sp.getString(domain, "");
        }

        return null;
    }
}

最后将这两个拦截器设置到OkHttpClient

OkHttpClient client = builder.addInterceptor(new AddCookiesInterceptor(context))
                .addInterceptor(new SaveCookiesInterceptor(context))
                .build();
Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(Constant.API_BASE)
                .addConverterFactory(GsonConverterFactory.create())
                .client(client)
                .build();

实际中的问题

在登录后保存了Cookie,但是请求我的收藏时,第一次是可以得到的,第二次则提示需要登录。输出保存的Cookie内容才发现其内容改变了。于是,将请求登录时只添加SaveCookiesInterceptor,其他请求只添加AddCookiesInterceptor。解决问题。

完整项目

鸿洋大神玩android网址→http://www.wanandroid.com/
完整项目地址→玩android

日记本
Gupao