(Unicode C) Refresh GMail IMAP OAuth2 Access Token

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

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#include <C_CkJsonObjectW.h>
#include <C_CkOAuth2W.h>
#include <C_CkStringBuilderW.h>

void ChilkatSample(void)
    {
    HCkJsonObjectW jsonToken;
    BOOL success;
    HCkOAuth2W oauth2;
    HCkStringBuilderW sbJson;

    // 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.

    jsonToken = CkJsonObjectW_Create();
    success = CkJsonObjectW_LoadFile(jsonToken,L"qa_data/tokens/_gmailFullAccess.json");
    if (success != TRUE) {
        wprintf(L"Failed to load _gmailFullAccess.json\n");
        CkJsonObjectW_Dispose(jsonToken);
        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"
    // 	}
    // 

    oauth2 = CkOAuth2W_Create();

    CkOAuth2W_putTokenEndpoint(oauth2,L"https://www.googleapis.com/oauth2/v4/token");

    // Replace these with actual values.
    CkOAuth2W_putClientId(oauth2,L"GOOGLE-CLIENT-ID");
    CkOAuth2W_putClientSecret(oauth2,L"GOOGLE-CLIENT-SECRET");

    // Get the "refresh_token"
    CkOAuth2W_putRefreshToken(oauth2,CkJsonObjectW_stringOf(jsonToken,L"refresh_token"));

    // Send the HTTP POST to refresh the access token..
    success = CkOAuth2W_RefreshAccessToken(oauth2);
    if (success != TRUE) {
        wprintf(L"%s\n",CkOAuth2W_lastErrorText(oauth2));
        CkJsonObjectW_Dispose(jsonToken);
        CkOAuth2W_Dispose(oauth2);
        return;
    }

    wprintf(L"New access token: %s\n",CkOAuth2W_accessToken(oauth2));

    // 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.
    CkJsonObjectW_UpdateString(jsonToken,L"access_token",CkOAuth2W_accessToken(oauth2));

    // Save the new JSON access token response to a file.
    sbJson = CkStringBuilderW_Create();
    CkJsonObjectW_putEmitCompact(jsonToken,FALSE);
    CkJsonObjectW_EmitSb(jsonToken,sbJson);
    CkStringBuilderW_WriteFile(sbJson,L"qa_data/tokens/_gmailFullAccess.json",L"utf-8",FALSE);

    wprintf(L"Access token refreshed!\n");
    wprintf(L"New Access Token = %s\n",CkOAuth2W_accessToken(oauth2));


    CkJsonObjectW_Dispose(jsonToken);
    CkOAuth2W_Dispose(oauth2);
    CkStringBuilderW_Dispose(sbJson);

    }