(.NET Core C#) Hotmail Refresh Access Token (also for Live.com, Outlook.com)

See more OAuth2 Examples

An OAuth2 access token is typically valid for 1 hour. Interaction with the Hotmail account owner via a browser is only needed for getting the initial access token. Once you have it, it can be continually refreshed without user interaction for a long time.

See: How Long can an OAuth2 Access Token be Refreshed?

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

// It is assumed we previously obtained an OAuth2 access token.

// Note: Refreshing an access token does not require user-interaction.  
// Only the act of getting the initial access token requires interactive authorization from the Hotmail account owner 
// (i.e. a browser is displayed and the Hotmail account owner authorizes access by the app).

// Once you have the initial access token, it can be refreshed for a long time.
// A typical strategy is to write your application to automatically refresh the access token 
// when authentication fails, and then retry the operation with the new access token.

Chilkat.JsonObject jsonToken = new Chilkat.JsonObject();
bool success = jsonToken.LoadFile("qa_data/tokens/hotmail.json");
if (success != true) {
    Debug.WriteLine("Failed to load office365.json");
    return;
}

// The access token JSON looks like this:

// {
//   "token_type": "Bearer",
//   "scope": "https://outlook.office.com/SMTP.Send https://outlook.office.com/IMAP.AccessAsUser.All https://outlook.office.com/POP.AccessAsUser.All",
//   "expires_in": 3600,
//   "ext_expires_in": 3600,
//   "access_token": "EwBoA+ ... 7pOYcWr5pFwQgI=",
//   "refresh_token": "M.C546_BL2.0.U.-CkW ... g5CKSlDBQ$$",
//   "id_token": "eyJ0e ... 2iiu5iqBK9n7s3A"
// }

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

// See Microsoft OAuth2 Authorization Endpoint
oauth2.TokenEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/token";

// Replace this with your actual App Registration's Application (client) ID.
oauth2.ClientId = "CLIENT_ID";

// 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(oauth2.LastErrorText);

Debug.WriteLine("New access token: " + oauth2.AccessToken);
Debug.WriteLine("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.
Chilkat.StringBuilder sbJson = new Chilkat.StringBuilder();
jsonToken.EmitCompact = false;
jsonToken.EmitSb(sbJson);
sbJson.WriteFile("qa_data/tokens/hotmail.json","utf-8",false);

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