How to get community API key in iFrame application?

Question

API

I don’t understand how to get the community key in the iFrame application in order to use it when updating the widget?
oauth does not fit here, although according to the documentation, the server should request this:

To get an access_token, you need to make a request from your server to https://oauth.vk.com/access_token, passing the following parameters:
client_id
required Your application ID
client_secret required Your application's
secure key (specified in the application settings)
redirect_uri
required URL that was used when receiving a code at the first stage of authorization. Should be similar to the one passed during authorization.
code
required Temporary code received after authorization.
Request example:
https://oauth.vk.com/access_token?client_id=1&clie...

Following the example, I prepared a request, but it is not clear where to get CODE. Later in the same documentation, we return to visitor authorization and Oauth. Some vicious circle.
If the application was given the rights to update the widget, then why can't I get this code in order to get the community API key and substitute it when updating the widget?

Answer 1

figured it out myself