Retry promise himself after fail in node js

Question

I would like to retry my request in a promise. I would like launch my refresh if I have always an 401 error as a loop : (if I have 401 loop on refresh until 200)

I tried with this :

const request = require('request');
let conf    = require('../conf');

let core_service = require('coreService');

let self = module.exports = {
    get_count_questions: function() {
        return new Promise((resolve, reject) => {
            request({
                method: 'GET',
                uri: 'http://api/count-questions',
                auth: {
                    'bearer': conf.token
                },
                json: true
            }, function (error, response, body) {
                if (!error && response.statusCode === 200) {
                    resolve(body);
                } else if (!error && response.statusCode === 401) {
                    core_service.refreshToken().then((data) => {
                        console.log('token refresh');
                        return self.get_count_questions();
                    })
                } else {
                    reject(error);
                }
            })
        });
    }
};

I tried with just 'self.get_count_questions();' without return, but it's not work. I have not error message, just my app freeze.

I see in my console.log "token refresh", but after my app freeze...

Edit

I modified with this, It's like better but the refresh token it's very slow. Just before 401, my app stop, and after about 1 minutes 40 seconds, run:

else if (!error && response.statusCode === 401) {
    console.log('need refresh token');
    core_service.refreshToken()
                .then((response) => {
                    console.log(response);
                    resolve(self.get_count_questions())
                } );
}

My refreshToken function :

refreshToken: function () {
    return new Promise((resolve, reject) => {
        request({
            method: 'GET',
            uri   : 'http://api/refresh',
            auth  : {
                'bearer': conf.token
            },
            json  : true
        }, function (error, response, body) {
            console.log('=====> refresh token <======');
            conf.token = body.data;
            console.log('new Token');
            console.log('=====> end refresh token <======');
            if (!error && response.statusCode === 200) {
                resolve('Refresh token successful');
            } else {
                reject('Error refresh');
            }
        })
    });
}

If I refresh my token on each request, I have a problem :

if (!error && response.statusCode === 200) {
     core_service.refreshToken().then((data)=> {
         resolve(body);
     });

}

Answer 1

You have to resolve the returned promise. When you resolve using a promise, you basically say, complete this promise with the result of that promise.

var prom = function() {
  return new Promise((resolve, reject) => {
    console.log('request start')
    setTimeout(() => {
      console.log('request finish')
      let ran = Math.random();

      if (ran < 0.1)
        resolve('success');

      else if (ran >= 0.1 && ran < 0.98)
        setTimeout(() => {
          console.log('retry');
          resolve(prom());
        }, 500);

      else
        reject('error');

    }, 500);
  });
};

prom().then(console.log.bind(console), console.log.bind(console));

So you should update your else if block like this:

else if (!error && response.statusCode === 401) {
  console.log('need refresh token');
  core_service.refreshToken()
    .then(() => resolve(self.get_count_questions()));
} 

Answer 2

Now you almost have it.

However:

return core_service.refreshToken()
                   .then(self.get_count_questions);

You're returning that to the request() callback; that return value is not used.

Instead, you need to resolve your original promise to the new promise from then(), by passing it to your original resolve() function:

resolve(core_service.refreshToken().then(...));

Answer 3

I know that is not optimal solution but it might helps

const request = require('request');
    let conf    = require('../conf');

    let core_service = require('coreService');

    let self = module.exports = {
        get_count_questions: function() {
            return new Promise((resolve, reject) => {
                request({
                    method: 'GET',
                    uri: 'http://api/count-questions',
                    auth: {
                        'bearer': conf.token
                    },
                    json: true
                }, function (error, response, body) {
             try{
                    if (!error && response.statusCode === 200) {
                        resolve(body);
                    } else if (!error && response.statusCode === 401) {
                       throw new Error(response.statusCode);
                    } else {
                        reject(error);
                    }
                 }catch(exc){if(exc === 401){
                            core_service.refreshToken().then((data) => {
                            console.log('token refresh');
                            return self.get_count_questions();
                        })      
                       }

                    }       
                })
            });
        }
    };