(Xojo Plugin) 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"
// }

Dim jsonToken As New Chilkat.JsonObject
Dim success As Boolean
success = jsonToken.LoadFile("qa_data/tokens/qb-access-token.json")

Dim rest As 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.
Dim bAutoReconnect As Boolean
bAutoReconnect = True
success = rest.Connect("sandbox-quickbooks.api.intuit.com",443,True,bAutoReconnect)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

Dim sbAuth As New Chilkat.StringBuilder
success = sbAuth.Append("Bearer ")
success = sbAuth.Append(jsonToken.StringOf("access_token"))
rest.Authorization = sbAuth.GetAsString()

success = rest.AddHeader("Accept","application/json")
rest.AllowHeaderFolding = False

// The company ID is 123146096291789
// The employee ID is 58
Dim responseBody As String
responseBody = rest.FullRequestNoBody("GET","/v3/company/123146096291789/employee/58?minorversion=45")
If (rest.LastMethodSuccess <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// 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) Then

    Dim oauth2 As 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) Then
        System.DebugLog(oauth2.LastErrorText)
        Return
    End If

    System.DebugLog("New access token: " + oauth2.AccessToken)

    // Update the JSON with the new tokens.
    success = 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.
    Dim sbJson As New Chilkat.StringBuilder
    jsonToken.EmitCompact = False
    success = jsonToken.EmitSb(sbJson)
    success = sbJson.WriteFile("qa_data/tokens/qb-access-token.json","utf-8",False)

    System.DebugLog("OAuth2 token refreshed!")
    System.DebugLog("New Access Token = " + oauth2.AccessToken)

    sbAuth.Clear 
    success = sbAuth.Append("Bearer ")
    success = 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) Then
        System.DebugLog(rest.LastErrorText)
        Return
    End If

End If

// We should expect a 200 response if successful.
If (rest.ResponseStatusCode <> 200) Then
    System.DebugLog("Request Header: ")
    System.DebugLog(rest.LastRequestHeader)
    System.DebugLog("----")
    System.DebugLog("Response StatusCode = " + Str(rest.ResponseStatusCode))
    System.DebugLog("Response StatusLine: " + rest.ResponseStatusText)
    System.DebugLog("Response Header:")
    System.DebugLog(rest.ResponseHeader)
    System.DebugLog(responseBody)
    Return
End If

// Load the JSON response into a JSON object for parsing.
// A sample JSON response is shown below.
Dim json As New Chilkat.JsonObject
success = json.Load(responseBody)

// These will be used for parsing date/time strings..
Dim dtime As New Chilkat.CkDateTime
Dim bLocalTime As Boolean
bLocalTime = True
Dim dt As Chilkat.DtObj

// Show the JSON.   
json.EmitCompact = False
System.DebugLog(json.Emit())

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

// Load the CreateTime into a CkDateTime...
success = dtime.SetFromTimestamp(json.StringOf("Employee.MetaData.CreateTime"))
dt = dtime.GetDtObj(bLocalTime)
System.DebugLog(Str(dt.Month) + "/" + Str(dt.Day) + "/" + Str(dt.Year) + "  " + Str(dt.Hour) + ":" + Str(dt.Minute))

System.DebugLog("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"
//