(Xojo Plugin) Refresh a Dynamics CRM OAuth2 Access Token

Demonstrates how to refresh an expiring Dynamics CRM access token using the refresh token. endpoint.

(If a REST API call fails with a 401 unauthorized error, an application can auto-recover by refreshing the access token, and then re-send the request using the new token.)

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

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

//  We previously obtained an access token and saved the JSON to a file using this example:
//  Get Dynamics CRM OAuth2 Access Token

//  This example will examine the JSON and expiration date, and if near expiration will
//  refresh the access token.

Dim json As New Chilkat.JsonObject
Dim success As Boolean
success = json.LoadFile("qa_data/tokens/dynamicsCrm.json")
If (success <> True) Then
    Return
End If

//  The contents of the JSON look like this:
//  {
//    "token_type": "Bearer",
//    "scope": "user_impersonation",
//    "expires_in": "3599",
//    "ext_expires_in": "0",
//    "expires_on": "1524783438",
//    "not_before": "1524779538",
//    "resource": "https://mydomain.api.crm.dynamics.com",
//    "access_token": "...",
//    "refresh_token": "...",
//    "id_token": "..."
//  }

//  The "expires_on" value is a Unix time.
Dim dtExpire As New Chilkat.CkDateTime
success = dtExpire.SetFromUnixTime(False,json.IntOf("expires_on"))

//  If this date/time expires within 10 minutes of the current system time, refresh the token.

//  OK, we need to refresh the access token by sending a POST...
// 

Dim req As New Chilkat.HttpRequest
req.AddParam "grant_type","refresh_token"
req.AddParam "redirect_uri","http://localhost:3017/"
req.AddParam "client_id","DYNAMICS-CRM-CLIENT-ID"
req.AddParam "client_secret","DYNAMICS-CRM-SECRET-KEY"
req.AddParam "refresh_token",json.StringOf("refresh_token")
req.AddParam "resource","https://mydynamicsdomain.api.crm.dynamics.com"

Dim http As New Chilkat.Http

Dim resp As Chilkat.HttpResponse
resp = http.PostUrlEncoded("https://login.microsoftonline.com/DYNAMICS-ENDPOINT-GUID/oauth2/token",req)
If (http.LastMethodSuccess <> True) Then
    System.DebugLog(http.LastErrorText)
    Return
End If

//  Load the JSON response.
success = json.Load(resp.BodyStr)
json.EmitCompact = False

//  Show the JSON response.
System.DebugLog(json.Emit())

System.DebugLog("Response status code: " + Str(resp.StatusCode))

//  If the response status code is not 200, then it's an error.
If (resp.StatusCode <> 200) Then
    Return
End If

//  If an "expires_on" member does not exist, then add the JSON member by
//  getting the current system date/time and adding the "expires_in" seconds.
//  This way we'll know when the token expires.
If (json.HasMember("expires_on") <> True) Then
    success = dtExpire.SetFromCurrentSystemTime()
    success = dtExpire.AddSeconds(json.IntOf("expires_in"))
    success = json.AppendString("expires_on",dtExpire.GetAsUnixTimeStr(False))
End If

//  Save the refreshed access token JSON to a file for future requests.
Dim fac As New Chilkat.FileAccess
success = fac.WriteEntireTextFile("qa_data/tokens/dynamicsCrm.json",json.Emit(),"utf-8",False)