Delphi DLL Requires Chilkat v10.1.2+

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.

Delphi DLL

var
success: Boolean;
oauth2: HCkOAuth2;
url: PWideChar;
numMsWaited: Integer;
json: HCkJsonObject;

begin
success := False;

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

oauth2 := CkOAuth2_Create();

//  The port should match the Authorized Redirect URL in your Dropbox app, 
//  which would look like "http://localhost:3017/"
CkOAuth2_putListenPort(oauth2,3017);

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

CkOAuth2_putAuthorizationEndpoint(oauth2,'https://www.dropbox.com/oauth2/authorize');
CkOAuth2_putTokenEndpoint(oauth2,'https://api.dropboxapi.com/oauth2/token');

//  Replace this with your actual Dropbox App Key
CkOAuth2_putClientId(oauth2,'DROPBOX_APP_KEY');

//  This is for Require Proof Key for Code Exchange (PKCE)
//  See OAuth2 PKCE Explained
CkOAuth2_putCodeChallenge(oauth2,True);
CkOAuth2_putCodeChallengeMethod(oauth2,'S256');

//  Add token_access_type=offline to also get a refresh token in the response
CkOAuth2_AddAuthQueryParam(oauth2,'token_access_type','offline');

//  Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
url := CkOAuth2__startAuth(oauth2);
if (CkOAuth2_getLastMethodSuccess(oauth2) = False) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

Memo1.Lines.Add('url = ' + url);

//  Launch the default browser on the system and navigate to the url.
//  The LaunchBrowser method was added in Chilkat v10.1.2.
success := CkOAuth2_LaunchBrowser(oauth2,url);
if (success = False) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

//  Wait for the user to approve or deny authorization in the browser.
numMsWaited := 0;
while (numMsWaited < 90000) and (CkOAuth2_getAuthFlowState(oauth2) < 3) do
  begin
    CkOAuth2_SleepMs(oauth2,100);
    numMsWaited := numMsWaited + 100;
  end;

//  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 (CkOAuth2_getAuthFlowState(oauth2) < 3) then
  begin
    CkOAuth2_Cancel(oauth2);
    Memo1.Lines.Add('No response from the browser!');
    Exit;
  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.

if (CkOAuth2_getAuthFlowState(oauth2) = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(CkOAuth2__failureInfo(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) = 4) then
  begin
    Memo1.Lines.Add('OAuth2 authorization was denied.');
    Memo1.Lines.Add(CkOAuth2__accessTokenResponse(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) <> 3) then
  begin
    Memo1.Lines.Add('Unexpected AuthFlowState:' + IntToStr(CkOAuth2_getAuthFlowState(oauth2)));
    Exit;
  end;

Memo1.Lines.Add('OAuth2 authorization granted!');

json := CkJsonObject_Create();
CkJsonObject_Load(json,CkOAuth2__accessTokenResponse(oauth2));
CkJsonObject_putEmitCompact(json,False);

Memo1.Lines.Add('Access Token Response = ' + CkJsonObject__emit(json));

//  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"
//  }

Memo1.Lines.Add('Access Token = ' + CkOAuth2__accessToken(oauth2));

//  Save the JSON access token response to a file for subsequent use..
CkJsonObject_WriteFile(json,'qa_data/tokens/dropbox.json');

CkOAuth2_Dispose(oauth2);
CkJsonObject_Dispose(json);