Android / RxJava How to link network requests and try again

Question

I am trying to bind network requests using RxJava in Android and then try again when it is not working. I looked at StackOverflow on how to do this without falling into the hellish hell of Callback that comes with using Vanilla Android and Retrofit alone. I can do all this in a procedure, in such an asynchronous task (below are the steps I need to do) to enter.

• User login with username / password
• Request SSO token if this response is successful
• Call the startup service with this sso token

I did this in AsyncTask, which worked only at login. However, the SSO token expires while using the application, so I need to make a request every time I see that it expires.

The code for AsyncTask is as follows:

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);
    }
}

My attempt to make this work with RxJava is similar to

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();
            }
        });

In this code I need to do the following

• When loginUserRx succeeds, I need to save the username and password in SavedPreferences
• Then I need to make a network request to get the sso token
• After that, I need to run the third and last network request.

The code right now simply calls the login login, and as soon as it succeeds, the asynchronous task starts. Ideally, I would like to combine the queries in a single query. I experimented with flatmap, mapetc., and can't figure out how to connect these calls when I went above.

Can anyone light this light? Thanks.

Answer 1

. , .

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();