How to generate access token using refresh token through google drive API?

Question

I have completed steps of authorization and obtained access token and refresh token.

What should I do next to generate access token using refresh token that I have s

Answer 1

POST /oauth2/v4/token

Host: www.googleapis.com

Headers

Content-length: 163

content-type: application/x-www-form-urlencoded

RequestBody

client_secret=************&grant_type=refresh_token&refresh_token=sasasdsa1312dsfsdf&client_id=************

Answer 2

Using ASP.Net Post call, this worked for me.

StringBuilder getNewToken = new StringBuilder();
getNewToken.Append("https://www.googleapis.com/oauth2/v4/token");                        
HttpClient client = new HttpClient();
client.BaseAddress = new Uri(getNewToken.ToString());
                    var values = new Dictionary<string, string>
                    {
                        { "client_id", <Your Client Id> },
                        { "client_secret", <Your Client Secret> },
                        { "refresh_token", <Your Saved Refresh Token> },
                        { "grant_type", "refresh_token"}
                    };

                    var content = new FormUrlEncodedContent(values);
                    var response = await client.PostAsync(getNewToken.ToString(), content);