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Ghislain Sommervogel's avatar
Ghislain Sommervogel
Helpful | Level 5
3 months ago

.NET SDK Invalid request while calling ProcessCodeFlowAsync

Hi Team, I'm trying to setup a permanent connection (= a refreshToken process) to my app using OauthPKCE. For this, I'm using the sample code provided here: https://github.com/dropbox/dropbox-sdk-d...
  • Greg-DB's avatar
    Greg-DB
    3 months ago

    If you're using the PKCE flow, the client secret shouldn't be required, so based on this error it looks like you're not actually in a PKCE flow.

     

    Have you modified the OAuthPKCE sample code? I just tried it as is (just plugging in an app key) and it is working for me.

     

    Can you confirm you set up the OAuthFlow object as a PKCEOAuthFlow as shown here and that the redirectUri you are passing in to ProcessCodeFlowAsync comes from the same flow started with the same object? (This error would occur if the authorization code you are exchanging wasn't actually retrieved using PKCE.)

Greg-DB's avatar
Greg-DB
Icon for Dropbox Staff rankDropbox Staff
3 months ago

If you're using the PKCE flow, the client secret shouldn't be required, so based on this error it looks like you're not actually in a PKCE flow.

 

Have you modified the OAuthPKCE sample code? I just tried it as is (just plugging in an app key) and it is working for me.

 

Can you confirm you set up the OAuthFlow object as a PKCEOAuthFlow as shown here and that the redirectUri you are passing in to ProcessCodeFlowAsync comes from the same flow started with the same object? (This error would occur if the authorization code you are exchanging wasn't actually retrieved using PKCE.)

  • Ghislain Sommervogel's avatar
    Ghislain Sommervogel
    Helpful | Level 5
    3 months ago

    Hello Greg,

    Thanks for leading me to the solution. I didn't use the sample code "as is" because I had to adapt a preexisting code. The mistake was to call the GetAuthorizeUri function of DropboxOAuth2Helper instead of PKCEOAuthFlow.

    Best regards,

    Ghislain

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