Android JWT refresh token flow

Issue

I'm implementing codes with jwt on Android.
At point of using refresh token, I'm not sure my code is correct way.

Here is sequene diagram of my flow.
Server issued access token and refresh token. These expire time is 1hour and 3 days. These token is saved to sharedpreferences.

Here is above diagram's description.

When access token is expired, http call will be failed with 401 error.
So I implemented getAccessToken() for re-newing access token.

(1) : One AsyncTask is used for this whole http call step.
- My AsyncTask is too big, I want to refactor it.
(2) : (1)'s AynsTask has a logic for re-getting access token.
- This logic was duplicated all my HTTP call functions.
(3) : After renewing access token, my app re-try to call /api/foo - To retry it, AsyncTask's doBackground() function is call recursivly.

Here is my code snippet.

class ApplyCheck extends AsyncTask<String, Void, ResponseTypeEnum> {
    private List<ApplyEntity> applyEntityList = null;

    @Override
    protected ResponseTypeEnum doInBackground(String... strings) {
        try {
            response = restManager.getApplyList(strings[0],"","","");  // call /api/foo
        } catch (RestRuntimeException e) {
            return ResponseTypeEnum.SERVER_ERROR;
        }

        switch (response.code()) {
            case 200:
                //set applyEntityList
                ....
                return ResponseTypeEnum.SUCCESS;
            case 401:
                //<-- This routine is duplcated all my AsyncTasks
                if(getAccessToken()) {
                    //<-- recursive call to re-call api 
                    return doInBackground(strings);
                } else {
                    return ResponseTypeEnum.TOKEN_EXPIRE;
                }
        }
    }

    //re-issue new access token
    private boolean getAccessToken() {
        Response response = restManager.getAccessToken();  // call /auth/issue-token
        if(response.code() == 200) {
            String tokens = response.body().string();
            JSONObject jsonObject = new JSONObject(tokens);
            sharedPreferences.edit().putString("accessToken", jsonObject.getString("accessToken"));
            sharedPreferences.edit().putString("refreshToken", jsonObject.getString("refreshToken"));
            return true;
        } else {
            return false;
        }  

My Questions
1. Is my approach correct? If not, please inform me good practice.
2. If yes, are any good practice for extracting common function for my duplicated AsyncTasks?

Solution

The process you have is fine IMHO. The only change is that I would not recursively call doInBackground. What you're doing is feasible, but it violates the intention of doInBackground. Rather modify your AsyncTask to cope with processing different responses in onPostExecute, (ie chaining your requests), and call the AsyncTask again with the relevant parameters for each use case. It will make it much easier to maintain as you can add specific methods to the AsyncTask to cope with each response type and can see how it's triggered in a linear way. If you need to update onProgressUpdate, you should also pass a progress value to the chained AsyncTask calls so it can maintain consistency on the progress. Otherwise it would keep restarting on each call.

Answered By - angryITguy