(Objective-C) Get Google API Access Token using P12 Service Account Key

Demonstrates how to get a Google API access token using a P12 service account key.

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

#import <CkoPfx.h>
#import <CkoAuthGoogle.h>
#import <NSString.h>
#import <CkoSocket.h>

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

// --------------------------------------------------------------------------------
// For a step-by-step guide for setting up your Google Workspace service account,
// see Setup Google Workspace Account for Sending SMTP GMail from a Service Account
// --------------------------------------------------------------------------------

// First load the PKCS12 (.p12 / .pfx) into a PFX object.
CkoPfx *pfx = [[CkoPfx alloc] init];
BOOL success = [pfx LoadPfxFile: @"qa_data/pfx/chilkat25-cbd7b42afbd8.p12" password: @"notasecret"];
if (success != YES) {
    NSLog(@"%@",pfx.LastErrorText);
    return;
}

CkoAuthGoogle *gAuth = [[CkoAuthGoogle alloc] init];
success = [gAuth SetP12: pfx];

// The ISS is your service account email address ending in gserviceaccount.com.
NSString *iss = @"chilkatsvc@chilkat25.iam.gserviceaccount.com";

// The scope is always the following string:
NSString *scope = @"https://mail.google.com/";

// The sub is your company email address
NSString *oauth_sub = @"info@chilkat.xyz";

// The access token is valid for this number of seconds.
int numSec = 3600;

gAuth.EmailAddress = iss;
gAuth.Scope = scope;
gAuth.ExpireNumSeconds = [NSNumber numberWithInt: numSec];
gAuth.SubEmailAddress = oauth_sub;

// Connect to www.googleapis.com
CkoSocket *tlsSock = [[CkoSocket alloc] init];
success = [tlsSock Connect: @"www.googleapis.com" port: [NSNumber numberWithInt: 443] ssl: YES maxWaitMs: [NSNumber numberWithInt: 5000]];
if (success != YES) {
    NSLog(@"%@",tlsSock.LastErrorText);
    return;
}

// Send the request to obtain the access token.
success = [gAuth ObtainAccessToken: tlsSock];
if (success != YES) {
    NSLog(@"%@",gAuth.LastErrorText);
    return;
}

// Examine the access token:
NSLog(@"%@%@",@"Access Token: ",gAuth.AccessToken);