B4X

IMAP Auto-Refresh Office365 Access Token

See more Office365 Examples

Demonstrates how to automatically recover from an expired access token when OAuth2 authentication fails in the IMAP protocol. If the server responds with "NO AUTHENTICATE failed.", then we refresh the access token and retry. B4X

Dim success As Boolean = False

'  An Office365 OAuth2 access token must first be obtained prior
'  to running this code.

'  Getting the OAuth2 access token for the 1st time requires the O365 account owner's 
'  interactive authorizaition via a web browser.  Afterwards, the access token
'  can be repeatedly refreshed automatically.

'  See the following examples for getting and refreshing an OAuth2 access token

'  Get Office365 SMTP/IMAP/POP3 OAuth2 Access Token
'  Refresh Office365 SMTP/IMAP/POP3 OAuth2 Access Token

'  First get our previously obtained OAuth2 access token.
Dim jsonToken As ChilkatJsonObject
jsonToken.Initialize
success = jsonToken.LoadFile("qa_data/tokens/office365.json")
If success = False Then
    Log("Failed to open the office365 OAuth JSON file.")
    Return
End If


Dim imap As ChilkatImap
imap.Initialize("imap")

imap.Ssl = True
imap.Port = 993

'  Connect to the Office365 IMAP server.
success = imap.Connect("outlook.office365.com")
If success <> True Then
    Log(imap.LastErrorText)
    Return
End If


'  Use OAuth2 authentication.
imap.AuthMethod = "XOAUTH2"

'  Login using our username (i.e. email address) and the access token for the password.
success = imap.Login("OFFICE365_EMAIL_ADDRESS", jsonToken.StringOf("access_token"))
If success <> True Then
    Dim loginLastErrorText As String = imap.LastErrorText

    '  If we're still connected to the mail server, then it means the server sent a non-success response,
    '  Such as:  NO AUTHENTICATE failed.
    If imap.IsConnected = True Then

        '  Refresh the OAuth2 access token, and if successful, save the new (refreshed) access token and try authenticating again.
        Dim oauth2 As ChilkatOAuth2
        oauth2.Initialize("oauth2")

        '  Use your actual Directory (tenant) ID instead of "112d7ed6-71bf-4eba-a866-738364321bfc"
        oauth2.TokenEndpoint = "https://login.microsoftonline.com/112d7ed6-71bf-4eba-a866-738364321bfc/oauth2/v2.0/token"

        '  Replace these with your Azure App Registration's actual values.
        oauth2.ClientId = "CLIENT_ID"
        oauth2.ClientSecret = "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
            Log(oauth2.LastErrorText)
            Return
        End If


        Log("New access token: " & oauth2.AccessToken)
        Log("New refresh token: " & oauth2.RefreshToken)

        '  Update the JSON with the new tokens.
        jsonToken.UpdateString("access_token", oauth2.AccessToken)
        jsonToken.UpdateString("refresh_token", oauth2.RefreshToken)

        '  Save the new JSON access token response to a file.
        Dim sbJson As ChilkatStringBuilder
        sbJson.Initialize
        jsonToken.EmitCompact = False
        jsonToken.EmitSb(sbJson)
        sbJson.WriteFile("qa_data/tokens/office365.json", "utf-8", False)

        Log("New Access Token = " & oauth2.AccessToken)

        '  Retry the login.
        success = imap.Login("OFFICE365_EMAIL_ADDRESS", jsonToken.StringOf("access_token"))
        If success = False Then
            Log(imap.LastErrorText)
            Return
        End If


    Else
        '  Show the last error text for the call to Login
        Log(loginLastErrorText)
        Return
    End If

Else
    Log("O365 OAuth authentication is successful.")
End If


'  Do something...
success = imap.SelectMailbox("Inbox")
If success <> True Then
    Log(imap.LastErrorText)
    Return
End If


'  Your application can continue to do other things in the IMAP session....

'  When finished, logout and close the connection.
success = imap.Logout
success = imap.Disconnect

Log("Finished.")