Objective-C

Authorization Code Flow with PKCE for Native Apps

See more Okta OAuth/OIDC Examples

Demonstrates the authorization code flow with Proof Key for Code Exchange (PKCE) for native apps. In Okta, your app should be defined as shown: Objective-C

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

BOOL success = NO;

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

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

// This should be the port in the Login redirect URI for your app.  
// Your app's Login redirect URI should be "http://localhost:3017/" if the port number is 3017.
oauth2.ListenPort = [NSNumber numberWithInt:3017];

oauth2.AuthorizationEndpoint = @"https://{yourOktaDomain}/oauth2/default/v1/authorize";
oauth2.TokenEndpoint = @"https://{yourOktaDomain}/oauth2/default/v1/token";

// Replace these with actual values.
oauth2.ClientId = @"OKTA_CLIENT_ID";
oauth2.ClientSecret = @"OKTA_CLIENT_SECRET";

oauth2.CodeChallenge = YES;
oauth2.IncludeNonce = YES;

// Make sure to include "offline_access" to get a refresh token included in the final JSON response.
// Add any additional needed scopes separated by space chars.
oauth2.Scope = @"openid offline_access";

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
NSString *url = [oauth2 StartAuth];
if (oauth2.LastMethodSuccess == NO) {
    NSLog(@"%@",oauth2.LastErrorText);
    return;
}

NSLog(@"%@%@",@"URL to load in browser: ",url);

// Launch the system's default browser navigated to the URL.
success = [oauth2 LaunchBrowser: url];
if (success == NO) {
    NSLog(@"%@",oauth2.LastErrorText);
    return;
}

// Now wait for the authorization.
// We'll wait for a max of 60 seconds.
int numMsWaited = 0;
while ((numMsWaited < 60000) && ([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!");
NSLog(@"%@%@",@"Access Token = ",oauth2.AccessToken);

// Get the full JSON response:
CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json Load: oauth2.AccessTokenResponse];
json.EmitCompact = NO;
NSLog(@"%@",[json Emit]);

// The JSON response looks like this:

// {
//   "access_token": "eyJraWQi ... Kn4IiEfOw",
//   "token_type": "Bearer",
//   "expires_in": 3600,
//   "scope": "offline_access openid",
//   "refresh_token": "0jCqotuuUegdjNzB9uuSsfGM2Cu5HnCHUxoJ0yhZ4rs",
//   "id_token": "eyJraWQiO ... 09WGEq3dTRmQF86PzJg"
// }

// Save the JSON to a file for future requests.
CkoFileAccess *fac = [[CkoFileAccess alloc] init];
[fac WriteEntireTextFile: @"qa_data/tokens/okta.json" fileData: [json Emit] charset: @"utf-8" includePreamble: NO];