OAuth 2 how to re-authenticate/refresh an expired token

[Mick282]

Hi all,

So I've managed to setup a O-Auth2 Power Automate function that will automatically use credentials to retrieve and return a access token. This Flow can be called by other Flows so long as they pass the credentials to it.

Now this works perfectly and the access token can be used to make API requests to the designated endpoint. The question is that the token only lasts 20 minutes and the returned access token also contains a line that indicates in seconds when it will expire. Is there a way to use this to setup a auto-refresh of the token if another Flow that's using this function takes longer than 20 minutes to call?

[v-litu-msft]

Hi @Mick282,

You could create a Do-Until action to put these actions into it, for we could control the recall times, we could initialize a integer variable before it, for example:

Best Regards,
Community Support Team _ Lin Tu
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[Mick282]

Thanks @v-litu-msft .

That's a good idea. How would this work from a perspective of updating the access token on a calling flow?

My flow used to get the access token is just a function that a second Flow uses to get the access token to then perform a action. Below is the second flow that actually performs an API action once it has retrieved the access token.

[Anonymous]

Hello, @Mick282 ! Could you explain how you filled in the fields from each action, please?

[Unkn0wn]

Hey @Mick282 , I'm also looking for the same. did you've figured out anything ?

[franciscooa]

I was also looking for a good suggestion to implement something like this.

Regards

[Mick282]

Wow it's been a while since I created this post. @franciscooa 

Are you looking for a solution to expiring tokens or overall? I've found a solution to the expiring token issue. Basically disregard the expiry time. Generate the the bearer access token and store it (I'm using the environment variable in the Dynamics dataverse). Subsequent API calls will attempt to use that token. I wrap this around a Scope step in Power Automate and and then add in a fail scope (i.e. if the attempt to use the current access token fails because it has expired) to generate and store a new access token if the try scope fails.

[franciscooa]

Hi @Mick282 !

Thanks for your answer. Meanwhile, I developed a flow that is checking a .txt file that has the "access_token" and the "expiration" fields. If the current time > expiration, I'll generate a new token and then update the txt file with the refreshed details. Maybe I can use the environment variables to store that, I guess.

Thanks for your suggestion. 

Regards

[oburgos]

It would be possible for you to share an example?

[FelixK]

I solved this in a different approach within one flow. 
1. HTT P to get the token on the first time and

2. Store it to a Variable "VARAuthToken"

Now i build the flow until the first time I use it to call the API. right after thist call i add a condition. 
3. Condition on the Response body of the previous  API call, In  my case the response on a invalid token looks like:

"body": {
"error": "invalid_token",
"error_description": "'exp' claim expired at Wed, 31 May 2023 14:27:36 GMT"
 }

So i check on this "Error" = "invalid token". If this condition is raised, then 

4. run  another Get Token http and update the initial variable set in Step 2. 
Note: The Condition = false path is left empty and the subseqence flow is then after the entire condition case.

this Looks like: