(C#) QuickBooks - Automatically Refresh Access Token with No User Interaction

Demonstrates how to automaticaly refresh an expired access token and retry the request after a 401 authorization error.

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

// Get our previously obtained OAuth2 access token, which should contain JSON like this:
// {
//   "expires_in": 3600,
//   "x_refresh_token_expires_in": 8726400,
//   "refresh_token": "L011546037639r ... 3vR2DrbOmg0Sdagw",
//   "access_token": "eyJlbmMiOiJBMTI4Q0 ... oETJEMbeggg",
//   "token_type": "bearer"
// }

Chilkat.JsonObject jsonToken = new Chilkat.JsonObject();
bool success = jsonToken.LoadFile("qa_data/tokens/qb-access-token.json");

Chilkat.Rest rest = new Chilkat.Rest();

// Connect using TLS.
// A single REST object, once connected, can be used for many Quickbooks REST API calls.
// The auto-reconnect indicates that if the already-established HTTPS connection is closed,
// then it will be automatically re-established as needed.
bool bAutoReconnect = true;
success = rest.Connect("sandbox-quickbooks.api.intuit.com",443,true,bAutoReconnect);
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

Chilkat.StringBuilder sbAuth = new Chilkat.StringBuilder();
sbAuth.Append("Bearer ");
sbAuth.Append(jsonToken.StringOf("access_token"));
rest.Authorization = sbAuth.GetAsString();

rest.AddHeader("Accept","application/json");
rest.AllowHeaderFolding = false;

// The company ID is 123146096291789
// The employee ID is 58
string responseBody = rest.FullRequestNoBody("GET","/v3/company/123146096291789/employee/58?minorversion=45");
if (rest.LastMethodSuccess != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// If we get a 401 authorization error, then it's likely because the access token expired.
// We can automatically refresh it without interaction from the user.
if (rest.ResponseStatusCode == 401) {

    Chilkat.OAuth2 oauth2 = new Chilkat.OAuth2();

    oauth2.TokenEndpoint = "https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer";

    // Replace these with actual values.
    oauth2.ClientId = "QUICKBOOKS-CLIENT-ID";
    oauth2.ClientSecret = "QUICKBOOKS-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 != true) {
        Debug.WriteLine(oauth2.LastErrorText);
        return;
    }

    Debug.WriteLine("New access token: " + oauth2.AccessToken);

    // Update the JSON with the new tokens.
    jsonToken.UpdateString("access_token",oauth2.AccessToken);

    // Save the new JSON access token response to a file.
    // The access + refresh tokens contained in this JSON will be needed for the next refresh.
    Chilkat.StringBuilder sbJson = new Chilkat.StringBuilder();
    jsonToken.EmitCompact = false;
    jsonToken.EmitSb(sbJson);
    sbJson.WriteFile("qa_data/tokens/qb-access-token.json","utf-8",false);

    Debug.WriteLine("OAuth2 token refreshed!");
    Debug.WriteLine("New Access Token = " + oauth2.AccessToken);

    sbAuth.Clear();
    sbAuth.Append("Bearer ");
    sbAuth.Append(oauth2.AccessToken);
    rest.Authorization = sbAuth.GetAsString();

    // Now retry the request with the refreshed access token...
    responseBody = rest.FullRequestNoBody("GET","/v3/company/123146096291789/employee/58?minorversion=45");
    if (rest.LastMethodSuccess != true) {
        Debug.WriteLine(rest.LastErrorText);
        return;
    }

}

// We should expect a 200 response if successful.
if (rest.ResponseStatusCode != 200) {
    Debug.WriteLine("Request Header: ");
    Debug.WriteLine(rest.LastRequestHeader);
    Debug.WriteLine("----");
    Debug.WriteLine("Response StatusCode = " + Convert.ToString(rest.ResponseStatusCode));
    Debug.WriteLine("Response StatusLine: " + rest.ResponseStatusText);
    Debug.WriteLine("Response Header:");
    Debug.WriteLine(rest.ResponseHeader);
    Debug.WriteLine(responseBody);
    return;
}

// Load the JSON response into a JSON object for parsing.
// A sample JSON response is shown below.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.Load(responseBody);

// These will be used for parsing date/time strings..
Chilkat.CkDateTime dtime = new Chilkat.CkDateTime();
bool bLocalTime = true;
Chilkat.DtObj dt = null;

// Show the JSON.   
json.EmitCompact = false;
Debug.WriteLine(json.Emit());

// Get some information from the JSON..
Debug.WriteLine("Name: " + json.StringOf("Employee.DisplayName"));
Debug.WriteLine("Id: " + json.StringOf("Employee.Id"));
Debug.WriteLine("City: " + json.StringOf("Employee.PrimaryAddr.City"));
Debug.WriteLine("PostalCode: " + json.StringOf("Employee.PrimaryAddr.PostalCode"));

// Load the CreateTime into a CkDateTime...
dtime.SetFromTimestamp(json.StringOf("Employee.MetaData.CreateTime"));
dt = dtime.GetDtObj(bLocalTime);
Debug.WriteLine(Convert.ToString(dt.Month) + "/" + Convert.ToString(dt.Day) + "/" + Convert.ToString(dt.Year) + "  " + Convert.ToString(dt.Hour)
     + ":" + Convert.ToString(dt.Minute));

Debug.WriteLine("Success.");

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

// ------------------------------------------------------
// The JSON response looks like this:

// {
//   "Employee": {
//     "SSN": "XXX-XX-XXXX",
//     "PrimaryAddr": {
//       "Id": "116",
//       "Line1": "45 N. Elm Street",
//       "City": "Middlefield",
//       "CountrySubDivisionCode": "CA",
//       "PostalCode": "93242"
//     },
//     "BillableTime": false,
//     "domain": "QBO",
//     "sparse": false,
//     "Id": "98",
//     "SyncToken": "0",
//     "MetaData": {
//       "CreateTime": "2015-07-24T09:34:35-07:00",
//       "LastUpdatedTime": "2015-07-24T09:34:35-07:00"
//     },
//     "GivenName": "Bill",
//     "FamilyName": "Miller",
//     "DisplayName": "Bill Miller",
//     "PrintOnCheckName": "Bill Miller",
//     "Active": true,
//     "PrimaryPhone": {
//       "FreeFormNumber": "234-525-1234"
//     }
//   },
//   "time": "2015-07-24T09:35:54.805-07:00"
//