Objective-C

Refresh GMail IMAP OAuth2 Access Token

See more GMail SMTP/IMAP/POP Examples

Demonstrates how to refresh an access token GMail IMAP read/write access. Objective-C

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

BOOL success = NO;

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

//  See Get GMail IMAP OAuth2 Access Token for Desktop App 
//  for sample code showing how to obtain a GMail IMAP read/write access token.

//  It is assumed we previously obtained an OAuth2 access token for GMail.

CkoJsonObject *jsonToken = [[CkoJsonObject alloc] init];
success = [jsonToken LoadFile: @"qa_data/tokens/_gmailFullAccess.json"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load _gmailFullAccess.json");
    return;
}

//  The access token JSON looks something like this:

//  	{ 
//  	 "access_token": "abac.Ci-ZabcdF37-NUrmSzxbHxTsMbtlN-uPfabcdAQN_2ekzj0s5ofCzRabcdTDMGaa2Q",
//  	 "token_type": "Bearer",
//  	 "expires_in": 3600,
//  	 "refresh_token": "1/lEe5abcdNJ77eOSDBabcdkQGVmDalkwabcdR2Hatbo"
//  	}
//  

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

oauth2.TokenEndpoint = @"https://www.googleapis.com/oauth2/v4/token";

//  Replace these with actual values.
oauth2.ClientId = @"GOOGLE-CLIENT-ID";
oauth2.ClientSecret = @"GOOGLE-CLIENT-SECRET";

//  Get the "refresh_token"
oauth2.RefreshToken = [jsonToken StringOf: @"refresh_token"];

//  Send the HTTP POST to refresh the access token..
success = [oauth2 RefreshAccessToken];
if (success != YES) {
    NSLog(@"%@",oauth2.LastErrorText);
    return;
}

NSLog(@"%@%@",@"New access token: ",oauth2.AccessToken);

//  The response contains a new access token, but we must keep
//  our existing refresh token for when we need to refresh again in the future.
[jsonToken UpdateString: @"access_token" value: oauth2.AccessToken];

//  Save the new JSON access token response to a file.
CkoStringBuilder *sbJson = [[CkoStringBuilder alloc] init];
jsonToken.EmitCompact = NO;
[jsonToken EmitSb: sbJson];
[sbJson WriteFile: @"qa_data/tokens/_gmailFullAccess.json" charset: @"utf-8" emitBom: NO];

NSLog(@"%@",@"Access token refreshed!");
NSLog(@"%@%@",@"New Access Token = ",oauth2.AccessToken);