Android/RxJava如何链接网络请求并在失败时重试

Question

我试图在Android中使用RxJava链接网络请求,然后在失败时重试.我一直在研究StackOverflow如何做到这一点,而没有进入单独使用vanilla Android和Retrofit的Callback地狱.我可以在一个过程中完成所有这一切,在这样的异步任务中(下面是我需要做的步骤)登录.

1. 使用用户名/密码登录用户
2. 如果响应成功,请求SSO令牌
3. 使用该sso令牌调用启动服务

我一直在这样做AsyncTask,只有在登录时才有效.但是,SSO令牌在应用程序使用时到期,所以每次看到它到期时我都需要发出请求.

AsyncTask的代码如下所示:

private class LoginUserTask extends AsyncTask<Void, Void, Void> {
    private final String LOG_TAG = LoginUserTask.class.getSimpleName();

    @Override
    protected Void doInBackground(Void... params) {
        OkHttpClient httpClient = ((TribeSocial) getApplication()).getHttpClient();

        // Login User
        GroupDockService groupDockLoginService =
                GroupDockServiceGenerator
                        .createService(GroupDockService.class,
                                httpClient, GroupDockUser.class, new GroupDockUserDeserializer());
        GroupDockUser groupDockUser = groupDockLoginService.loginUser("Tribe", username, password);
        Utility.saveAccountSubdomain(mContext, groupDockUser.getGroupDockSubdomain().getSubdomain());

        // Get Sso Token
        GroupDockService groupDockService = GroupDockServiceGenerator
                .createService(GroupDockService.class, httpClient);
        GroupDockSsoResponse ssoResponse =
                groupDockService.getSsoToken(Utility.getAccountSubdomain(mContext), true);
        Utility.saveSsoToken(mContext, ssoResponse.getSsoToken());

        // Sign in user into Tribe service
        TribeSocialService tribeSocialLaunchService =
                TribeServiceGenerator.createService(TribeSocialService.class,
                        httpClient, new LenientGsonConverter(new Gson()));
        tribeSocialLaunchService.launch(Utility.getSsoToken(mContext));

        // Get User id and save it to SharedPreferences
        TribeSocialService tribeSocialWhoAmIService =
                TribeServiceGenerator.createService(TribeSocialService.class, httpClient,
                        User.class, new WhoAmIDeserializer());
        User tribeUser = tribeSocialWhoAmIService.whoami();
        Utility.saveUserId(mContext, tribeUser.getId());

        return null;
    }

    @Override
    protected void onPostExecute(Void v) {
        Utility.launchMainActivity(mContext);
    }
}

我尝试使用RxJava进行这项工作就像是

GroupDockService groupDockLoginService =
        GroupDockServiceGenerator
                .createService(GroupDockService.class,
                        mHttpClient, GroupDockUser.class, new GroupDockUserDeserializer());

groupDockLoginService
        .loginUserRx("Tribe", username, password)
        .subscribeOn(Schedulers.newThread())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Subscriber<GroupDockUser>() {
            @Override
            public void onCompleted() {

            }

            @Override
            public void onError(Throwable e) {
                Log.e(LOG_TAG, "I have errored out: " + e.getMessage());
                Toast.makeText(mContext,
                        getString(R.string.username_and_or_password_is_incorrect),
                        Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNext(GroupDockUser groupDockUser) {
                Utility.saveUsernamePassword(mContext, username, password);
                new LoginUserTask().execute();
            }
        });

在该代码中,我需要执行以下操作

1. 当loginUserRx成功时,我需要将用户名和密码保存到SavedPreferences中
2. 然后我需要发出网络请求来获取sso令牌
3. 之后,我需要发布第三个也是最后一个网络请求.

该代码现在只需拨打电话时登录用户,并且一旦成功,揭开序幕异步任务.理想情况下,我想在一个请求中将所有请求链接在一起.我一直在试验flatmap,map等等,当我走出上面时,无法弄清楚如何链接这些调用.

任何人都可以对此有所启发吗？谢谢.

Answer 1

看看这个例子.希望,它会激励你.

service
        //do login
        .loginUser()
        //side effect: save into Shared Preference
        .doOnNext( )
        //get SSO
        .flatMap()
        //do any other side effects
        .doOnNext()
        //do final network request
        .flatMap()
        //in case of error retry after 5 seconds
        .retryWhen(observable -> Observable.timer(5, TimeUnit.SECONDS))
        .subscribeOn(Schedulers.computation())
        .observeOn(AndroidSchedulers.mainThread())
        //update you UI
        .subscribe();

关于重试的进一步阅读