(Objective-C) Dropbox: OAuth2 Authorization to Obtain an Access Token

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.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoOAuth2.h>
#import <NSString.h>
#import <CkoJsonObject.h>

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Note: This example requires Chilkat v9.5.0.66 or greater to work properly.

CkoOAuth2 *oauth2 = [[CkoOAuth2 alloc] init];
BOOL success;

// The port should match the Authorized Redirect URL in your Dropbox app, 
// which would look like "http://localhost:3017/"
oauth2.ListenPort = [NSNumber numberWithInt:3017];

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

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

// Replace these with actual values.
oauth2.ClientId = @"DROPBOX_APP_KEY";
oauth2.ClientSecret = @"DROPBOX_APP_SECRET";
oauth2.CodeChallenge = NO;

// Add token_access_type=offline to also get a refresh token in the response
[oauth2 AddAuthQueryParam: @"token_access_type" value: @"offline"];

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
NSString *url = [oauth2 StartAuth];
if (oauth2.LastMethodSuccess != YES) {
    NSLog(@"%@",oauth2.LastErrorText);
    return;
}

// At this point, your application should load the URL in a browser.
// For example, 
// in C#: System.Diagnostics.Process.Start(url);
// in Java: Desktop.getDesktop().browse(new URI(url));
// in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//              wsh.Run url
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
// The Microsoft account owner would interactively accept or deny the authorization request.

// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...

// Now wait for the authorization.
// We'll wait for a max of 30 seconds.
int numMsWaited = 0;
while ((numMsWaited < 30000) && ([oauth2.AuthFlowState intValue] < 3)) {
    [oauth2 SleepMs: [NSNumber numberWithInt: 100]];
    numMsWaited = numMsWaited + 100;
}

// If there was no response from the browser within 30 seconds, then 
// the AuthFlowState will be equal to 1 or 2.
// 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
// 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
// In that case, cancel the background task started in the call to StartAuth.
if ([oauth2.AuthFlowState intValue] < 3) {
    [oauth2 Cancel];
    NSLog(@"%@",@"No response from the browser!");
    return;
}

// Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
// The possible AuthFlowState values are:
// 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
// 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
// 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
if ([oauth2.AuthFlowState intValue] == 5) {
    NSLog(@"%@",@"OAuth2 failed to complete.");
    NSLog(@"%@",oauth2.FailureInfo);
    return;
}

if ([oauth2.AuthFlowState intValue] == 4) {
    NSLog(@"%@",@"OAuth2 authorization was denied.");
    NSLog(@"%@",oauth2.AccessTokenResponse);
    return;
}

if ([oauth2.AuthFlowState intValue] != 3) {
    NSLog(@"%@%d",@"Unexpected AuthFlowState:",[oauth2.AuthFlowState intValue]);
    return;
}

NSLog(@"%@",@"OAuth2 authorization granted!");

CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json Load: oauth2.AccessTokenResponse];
json.EmitCompact = NO;

NSLog(@"%@%@",@"Access Token Response = ",[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"
// }

NSLog(@"%@%@",@"Access Token = ",oauth2.AccessToken);

// Save the JSON access token response to a file for subsequent use..
[json WriteFile: @"qa_data/tokens/dropbox.json"];