"error_description": "missing required field \"grant_type\""

Hi emretezisci,

Haha..😁 Ok, Yes, a little confusing message, maybe. Don't catch to the words. What grant type you are declaring in fact? 🧐 Nothing? 🤔 🙃 It's something required, cannot be nothing. 😉

Hope this gives direction.

Oh I think it was deducted for some reason. 

{
  "body": {
    "grant_type": "refresh_token",
    "refresh_token": "<token>"
  },
  "contentType": "application/json",
  "followRedirect": false,
  "headers": [
    {
      "key": "Authorization",
      "value": "Basic <key>"
    }
  ],
  "method": "POST",
  "timeoutSeconds": 5,
  "url": "https://api.dropbox.com/oauth2/token"
}

I use refresh_token. 

In addition why are you using application/json encoding? It requires application/x-www-form-urlencoded POST parameters. 😉

Thanks, for your prompt responses. I am making these requests from another integration that doesn't support application/x-www-form-urlencoded.

Do you know any other way to make it work with an application/json encoding?

To be honest, I haven't tried (haven't need), but you may do it by "hands". Shouldn't be so difficult to join names and value using = and & (no additional encoding steps needed in particular - all value are URL compatible already). Right? 🙂

emretezisci The /oauth2/token endpoint does not support those parameters being passed as "application/json"; they'll need to be passed as "application/x-www-form-urlencoded".

While it is recommended to use some library or platform functionality to have that built automatically, as Здравко said you can otherwise try to build that directly.

Is there any other server-side authentication option that doesn't require "application/x-www-form-urlencoded"?

emretezisci There isn't another endpoint for using a refresh token to get a new short-lived access token.

If your platform doesn't natively provide support for writing the data as "application/x-www-form-urlencoded", I suggest checking your platform's documentation to see how you can supply a string instead so you can build the parameters in your own code, and also override the "Content-Type" header with "application/x-www-form-urlencoded".

Greg-DBHi, I encountered the same problem despite using the x-www-form-url encoded. I'm using ESP32 MCU to get the token. 

My config for the HTTP is as follows:

The error output is as follows:

Is there any wrong config on the HTTP?

Thanks!

Hi trailtech,

We are not familiar with the esp_http_client component, but based on the error you are receiving from the API it's most likely the payload is not being formed correctly. Would it be possible for you to add logging that would allow you to visualize the full request payload before it is being sent to the Dropbox API?