What's the correct way to handle expired access token

Hello, after user authenticates via OAuth2 I request refresh token, which I store on user's mobile device. Now to perform various actions (upload/download) from the user's Dropbox storage, I build: ...

API

Здравко
2 years ago
Hi again cjacky475,
As seems the spam filter has caught your post 🤷 It happens from time to time - fake positive detection.

cjacky475 wrote:
...
As from my current understanding, SDK updates the token internally for the current client. After I create client again, I provide the old access token and the refresh process starts again. Each time I instantiate the client, refresh will happen, until I manually call the refresh token method, get the access token, and save it, right?
In general Yes, but not need to perform it manually. Something more: DbxCredential class with nested classes and static objects ('JsonWriter<DbxCredential> Writer' and 'JsonReader<DbxCredential> Reader') make store and read entire credentials information much more easy and less error prone. Updating the access token only is insecure. The client updates everything needed within DbxCredetial object. 😉 Saving entire content and read back whenever needed (on next client object construction) is the best practice (in spite not something mandatory).

cjacky475 wrote:
...
This way SDK will be refreshing the access token, since I always provide the old access token.

Greg-DB wrote:
And as Здравко said, it is not required, but you can retrieve the current access token using DbxCredential.getAccessToken if you want.
The access token stored in the DbxCredential object that I used to create the DbxClientV2 stores the old access token.
...
Whenever needed (i.e. when valid access token is needed, but the previous one is expired already) the client will update all needed in the passed DbxCredential object. Yes, if the passed object contains only outdated data (including access token), refresh will be forced on every first operation. Something no best when client objects are going to construct relatively often - it's unlikely refresh to be mandatory/needed every single time. That's why the information in credential object is good to be stored at the object work finish (not only the access token). So when read the next time, the information will be actual.

cjacky475 wrote:
...
My question again: after I instantiate user, perform some operations, how to get the updated access token? Can I get it from the client object? The SDK automatically refreshes the access token and where does it store it for me to access it? Thanks.
...
Let's think a bit...🤔 There are different ways an argument to be passed to a method/constructor. They commonly are divided to passed by value and passed by reference. Do you know how are they distinct? 🧐 ... and what are you using actually in your code? 😕... 😯😁
Hope this gives some directions... of thinking. 😉