(DataFlex) Dropbox: OAuth2 Authorization to Obtain an Access Token

See more Dropbox Examples

This example runs the OAuth 2.0 authorization flow that lets the user sign in to Dropbox and authorize your app.

Note: This example requires Chilkat v10.1.2 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoOauth2
    Boolean iSuccess
    String sUrl
    Boolean iSuccess
    Integer iNumMsWaited
    Handle hoJson
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

    // For more information about the OAuth2, see OAuth 2.0 Authorization Flow

    Get Create (RefClass(cComChilkatOAuth2)) To hoOauth2
    If (Not(IsComObjectCreated(hoOauth2))) Begin
        Send CreateComObject of hoOauth2
    End

    // The port should match the Authorized Redirect URL in your Dropbox app, 
    // which would look like "http://localhost:3017/"
    Set ComListenPort Of hoOauth2 To 3017

    // IMPORTANT: One of the OAuth2 redirect URIs for your Dropbox app must be
    // exactly this string:  http://localhost:3017/

    Set ComAuthorizationEndpoint Of hoOauth2 To "https://www.dropbox.com/oauth2/authorize"
    Set ComTokenEndpoint Of hoOauth2 To "https://api.dropboxapi.com/oauth2/token"

    // Replace this with your actual Dropbox App Key
    Set ComClientId Of hoOauth2 To "DROPBOX_APP_KEY"

    // This is for Require Proof Key for Code Exchange (PKCE)
    // See OAuth2 PKCE Explained
    Set ComCodeChallenge Of hoOauth2 To True
    Set ComCodeChallengeMethod Of hoOauth2 To "S256"

    // Add token_access_type=offline to also get a refresh token in the response
    Get ComAddAuthQueryParam Of hoOauth2 "token_access_type" "offline" To iSuccess

    // Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
    Get ComStartAuth Of hoOauth2 To sUrl
    Get ComLastMethodSuccess Of hoOauth2 To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoOauth2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "url = " sUrl

    // Launch the default browser on the system and navigate to the url.
    // The LaunchBrowser method was added in Chilkat v10.1.2.
    Get ComLaunchBrowser Of hoOauth2 sUrl To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoOauth2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Wait for the user to approve or deny authorization in the browser.
    Move 0 To iNumMsWaited
    While ((iNumMsWaited < 90000) And ((ComAuthFlowState(hoOauth2)) < 3))
        Send ComSleepMs To hoOauth2 100
        Move (iNumMsWaited + 100) To iNumMsWaited
    Loop

    // If the browser does not respond within the specified time, AuthFlowState will be:
    // 
    // 1: Waiting for Redirect - The OAuth2 background thread is waiting for the browser's redirect request.
    // 2: Waiting for Final Response - The thread is awaiting the final access token response.
    // In either case, cancel the background task initiated by StartAuth.

    Get ComAuthFlowState Of hoOauth2 To iTemp1
    If (iTemp1 < 3) Begin
        Get ComCancel Of hoOauth2 To iSuccess
        Showln "No response from the browser!"
        Procedure_Return
    End

    // Check AuthFlowState to determine if authorization was granted, denied, or failed:
    // 
    // 3: Success - OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
    // 4: Access Denied - OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
    // 5: Failure - OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

    Get ComAuthFlowState Of hoOauth2 To iTemp1
    If (iTemp1 = 5) Begin
        Showln "OAuth2 failed to complete."
        Get ComFailureInfo Of hoOauth2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComAuthFlowState Of hoOauth2 To iTemp1
    If (iTemp1 = 4) Begin
        Showln "OAuth2 authorization was denied."
        Get ComAccessTokenResponse Of hoOauth2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComAuthFlowState Of hoOauth2 To iTemp1
    If (iTemp1 <> 3) Begin
        Get ComAuthFlowState Of hoOauth2 To iTemp1
        Showln "Unexpected AuthFlowState:" iTemp1
        Procedure_Return
    End

    Showln "OAuth2 authorization granted!"

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComAccessTokenResponse Of hoOauth2 To sTemp1
    Get ComLoad Of hoJson sTemp1 To iSuccess
    Set ComEmitCompact Of hoJson To False

    Get ComEmit Of hoJson To sTemp1
    Showln "Access Token Response = " sTemp1

    // A sample access token response:

    // {
    //   "access_token": "...",
    //   "token_type": "bearer",
    //   "expires_in": 14399,
    //   "refresh_token": "...",
    //   "scope": "account_info.read",
    //   "uid": "562542581",
    //   "account_id": "dbid:AACQhDS0E3_Vb72Ynd0F-GxGWdTI2qcTHzA"
    // }

    Get ComAccessToken Of hoOauth2 To sTemp1
    Showln "Access Token = " sTemp1

    // Save the JSON access token response to a file for subsequent use..
    Get ComWriteFile Of hoJson "qa_data/tokens/dropbox.json" To iSuccess


End_Procedure