Refactor OAuth2 token exchange and refresh error handling

src/api/admin.rs

@@ -452,11 +452,7 @@ async fn oauth2_callback(params: OAuth2CallbackParams) -> Result<Html<String>, E
         ("client_secret", &client_secret),
     ];
 
-    let response = match make_http_request(Method::POST, &token_url)?
-        .form(&form_params)
-        .send()
-        .await
-    {
+    let response = match make_http_request(Method::POST, &token_url)?.form(&form_params).send().await {
         Ok(res) => res,
         Err(e) => err!(format!("OAuth2 Token Exchange Error: {e}")),
     };

src/config.rs

@@ -898,7 +898,7 @@ make_config! {
         /// SMTP OAuth2 Refresh Token |> OAuth2 Refresh Token for obtaining new access tokens
         smtp_oauth2_refresh_token:     Pass,   true,   option;
         /// SMTP OAuth2 Scopes |> Comma-separated list of OAuth2 scopes
-        smtp_oauth2_scopes:            String, true,   def,     "".to_string();
+        smtp_oauth2_scopes:            String, true,   def,     String::new();
         /// SMTP connection timeout |> Number of seconds when to stop trying to connect to the SMTP server
         smtp_timeout:                  u64,    true,   def,     15;
         /// Server name sent during HELO |> By default this value should be the machine's hostname, but might need to be changed in case it trips some anti-spam filters

src/mail.rs

@@ -56,11 +56,7 @@ pub async fn refresh_oauth2_token() -> Result<OAuth2Token, Error> {
         ("client_secret", &client_secret),
     ];
 
-    let response = match make_http_request(reqwest::Method::POST, &token_url)?
-        .form(&form_params)
-        .send()
-        .await
-    {
+    let response = match make_http_request(reqwest::Method::POST, &token_url)?.form(&form_params).send().await {
         Ok(res) => res,
         Err(e) => err!(format!("OAuth2 Token Refresh Error: {e}")),
     };