(.NET Core C#) Office365 OAuth2 Access Token for SMTP, IMAP, POP

See more Office365 Examples

Demonstrates how to get an OAuth2 access token for use in the SMTP, IMAP, and POP3 protocols.

Note: It is only the initial access token that must be obtained interactively using a browser (see the code and comments below). Once the initial OAuth2 access token is obtained, then it can refreshed indefinitely with no user interaction.

Chilkat .NET Downloads Chilkat .NET Assemblies Chilkat for .NET Core Chilkat for Mono

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

// -----------------------------------------------------------------------------------------------
// Important:  Setup your App Registration in Azure beforehand.  
// 
// See Create Azure App Registration for use with IMAP, POP3, and SMTP
// 
// Also, a detail that is often missed.  Make sure to specify "Web" for your Redirect URI.
// See Solution for Azure OAuth2 Error: Public clients can't send a client secret.
// -----------------------------------------------------------------------------------------------

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

// This should be the port in the localhost callback URL for your app.  
// The callback URL would look like "http://localhost:3017/" if the port number is 3017.
oauth2.ListenPort = 3017;

// Specify your OAuth2 authorization and token endpoints
// Replace "xxxxxxxxxx-71bf-4ebe-a866-738364321bf2" with your tenant ID, 
// or one of the following keywords: "common", "organizations", "consumers".
// 
// For more information about the /authorize endpoint, see Microsoft identity platform and OAuth 2.0 authorization code flow 

oauth2.AuthorizationEndpoint = "https://login.microsoftonline.com/xxxxxxxxxx-71bf-4ebe-a866-738364321bf2/oauth2/v2.0/authorize";
oauth2.TokenEndpoint = "https://login.microsoftonline.com/xxxxxxxxxx-71bf-4ebe-a866-738364321bf2/oauth2/v2.0/token";

// Replace these with actual values.
oauth2.ClientId = "CLIENT_ID";
oauth2.ClientSecret = "CLIENT_SECRET";

oauth2.CodeChallenge = false;

// Provide a SPACE separated list of scopes.
// Important: The offline_access scope is needed to get a refresh token.
oauth2.Scope = "openid profile offline_access https://outlook.office365.com/SMTP.Send https://outlook.office365.com/POP.AccessAsUser.All https://outlook.office365.com/IMAP.AccessAsUser.All";

// ----------------------------------------------------------------------
// Note: It is only the initial access token that must be obtained interactively using a browser.  
// Once the initial OAuth2 access token is obtained, then it can refreshed indefinitely with no user interaction.
// ----------------------------------------------------------------------

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
string url = oauth2.StartAuth();
if (oauth2.LastMethodSuccess != true) {
    Debug.WriteLine(oauth2.LastErrorText);
    return;
}

// At this point, your application should load the URL in a browser.
// For example, 
// in C#: System.Diagnostics.Process.Start(url);
// in Java: Desktop.getDesktop().browse(new URI(url));
// in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//              wsh.Run url
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
// The Microsoft account owner would interactively accept or deny the authorization request.

// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...

// ----------------------------------------------------------------------
// Note: Read about how browser caching of credentials can cause problems.
// See OAuth2 Browser Caching Credentials
// ----------------------------------------------------------------------

// Now wait for the authorization.
// We'll wait for a max of 90 seconds.
int numMsWaited = 0;
while ((numMsWaited < 90000) && (oauth2.AuthFlowState < 3)) {
    oauth2.SleepMs(100);
    numMsWaited = numMsWaited + 100;
}

// If there was no response from the browser within 30 seconds, then 
// the AuthFlowState will be equal to 1 or 2.
// 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
// 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
// In that case, cancel the background task started in the call to StartAuth.
if (oauth2.AuthFlowState < 3) {
    oauth2.Cancel();
    Debug.WriteLine("No response from the browser!");
    return;
}

// Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
// The possible AuthFlowState values are:
// 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
// 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
// 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
if (oauth2.AuthFlowState == 5) {
    Debug.WriteLine("OAuth2 failed to complete.");
    Debug.WriteLine(oauth2.FailureInfo);
    return;
}

if (oauth2.AuthFlowState == 4) {
    Debug.WriteLine("OAuth2 authorization was denied.");
    Debug.WriteLine(oauth2.AccessTokenResponse);
    return;
}

if (oauth2.AuthFlowState != 3) {
    Debug.WriteLine("Unexpected AuthFlowState:" + Convert.ToString(oauth2.AuthFlowState));
    return;
}

Debug.WriteLine("OAuth2 authorization granted!");
Debug.WriteLine("Access Token = " + oauth2.AccessToken);

// Get the full JSON response:
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.Load(oauth2.AccessTokenResponse);
json.EmitCompact = false;

// The JSON response looks like this:
// 
// {
//   "token_type": "Bearer",
//   "scope": "IMAP.AccessAsUser.All openid POP.AccessAsUser.All profile SMTP.Send email",
//   "expires_in": 3599,
//   "ext_expires_in": 3599,
//   "access_token": "...",
//   "refresh_token": "...",
//   "id_token": "...",
//   "expires_on": "1592748507"
// }

Debug.WriteLine(json.Emit());

// Save the JSON to a file for future requests.
Chilkat.FileAccess fac = new Chilkat.FileAccess();
fac.WriteEntireTextFile("qa_data/tokens/office365.json",json.Emit(),"utf-8",false);