PowerBuilder

Dropbox: OAuth2 Authorization to Obtain an Access Token

See more Dropbox Examples

Demonstrates how to get a Dropbox OAuth2 access token from a desktop application or script.

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

PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Oauth2
string ls_Url
integer li_NumMsWaited
oleobject loo_Json

li_Success = 0

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

loo_Oauth2 = create oleobject
li_rc = loo_Oauth2.ConnectToNewObject("Chilkat.OAuth2")
if li_rc < 0 then
    destroy loo_Oauth2
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// The port should match the Authorized Redirect URL in your Dropbox app, 
// which would look like "http://localhost:3017/"
loo_Oauth2.ListenPort = 3017

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

loo_Oauth2.AuthorizationEndpoint = "https://www.dropbox.com/oauth2/authorize"
loo_Oauth2.TokenEndpoint = "https://api.dropboxapi.com/oauth2/token"

// Replace this with your actual Dropbox App Key
loo_Oauth2.ClientId = "DROPBOX_APP_KEY"

// This is for Require Proof Key for Code Exchange (PKCE)
// See OAuth2 PKCE Explained
loo_Oauth2.CodeChallenge = 1
loo_Oauth2.CodeChallengeMethod = "S256"

// Add token_access_type=offline to also get a refresh token in the response
loo_Oauth2.AddAuthQueryParam("token_access_type","offline")

// Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
ls_Url = loo_Oauth2.StartAuth()
if loo_Oauth2.LastMethodSuccess <> 1 then
    Write-Debug loo_Oauth2.LastErrorText
    destroy loo_Oauth2
    return
end if

Write-Debug "url = " + ls_Url

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
li_Success = loo_Oauth2.LaunchBrowser(ls_Url)
if li_Success = 0 then
    Write-Debug loo_Oauth2.LastErrorText
    destroy loo_Oauth2
    return
end if

// Wait for the user to approve or deny authorization in the browser.
li_NumMsWaited = 0
do while (li_NumMsWaited < 90000) AND (loo_Oauth2.AuthFlowState < 3)
    loo_Oauth2.SleepMs(100)
    li_NumMsWaited = li_NumMsWaited + 100
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.

if loo_Oauth2.AuthFlowState < 3 then
    loo_Oauth2.Cancel()
    Write-Debug "No response from the browser!"
    destroy loo_Oauth2
    return
end if

// 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.

if loo_Oauth2.AuthFlowState = 5 then
    Write-Debug "OAuth2 failed to complete."
    Write-Debug loo_Oauth2.FailureInfo
    destroy loo_Oauth2
    return
end if

if loo_Oauth2.AuthFlowState = 4 then
    Write-Debug "OAuth2 authorization was denied."
    Write-Debug loo_Oauth2.AccessTokenResponse
    destroy loo_Oauth2
    return
end if

if loo_Oauth2.AuthFlowState <> 3 then
    Write-Debug "Unexpected AuthFlowState:" + string(loo_Oauth2.AuthFlowState)
    destroy loo_Oauth2
    return
end if

Write-Debug "OAuth2 authorization granted!"

loo_Json = create oleobject
li_rc = loo_Json.ConnectToNewObject("Chilkat.JsonObject")

loo_Json.Load(loo_Oauth2.AccessTokenResponse)
loo_Json.EmitCompact = 0

Write-Debug "Access Token Response = " + loo_Json.Emit()

// 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"
// }

Write-Debug "Access Token = " + loo_Oauth2.AccessToken

// Save the JSON access token response to a file for subsequent use..
loo_Json.WriteFile("qa_data/tokens/dropbox.json")


destroy loo_Oauth2
destroy loo_Json