fix: bail early if no printers on the network (electron#22418)

codebytere · web-flow · commit e8c628ecdf0b · 2020-03-04T02:20:31.000Z
diff --git a/docs/api/web-contents.md b/docs/api/web-contents.md
@@ -1286,7 +1286,7 @@ Returns [`PrinterInfo[]`](structures/printer-info.md)
   `A4`, `A5`, `Legal`, `Letter`, `Tabloid` or an Object containing `height`.
 * `callback` Function (optional)
   * `success` Boolean - Indicates success of the print call.
-  * `failureReason` String - Called back if the print fails; can be `cancelled` or `failed`.
+  * `failureReason` String - Error description called back if the print fails.
 
 Prints window's web page. When `silent` is set to `true`, Electron will pick
 the system's default printer if `deviceName` is empty and the default settings for printing.
diff --git a/shell/browser/api/electron_api_web_contents.cc b/shell/browser/api/electron_api_web_contents.cc
@@ -1766,6 +1766,14 @@ void WebContents::OnGetDefaultPrinter(
 
   base::string16 printer_name =
       device_name.empty() ? default_printer : device_name;
+
+  // If there are no valid printers available on the network, we bail.
+  if (printer_name.empty() || !IsDeviceNameValid(printer_name)) {
+    if (print_callback)
+      std::move(print_callback).Run(false, "no valid printers available");
+    return;
+  }
+
   print_settings.SetStringKey(printing::kSettingDeviceName, printer_name);
 
   auto* print_view_manager =
