Post to organization page from php
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I have an account in facebook, and a page of organization on this account. I need post to page of organization. I reed many articles about it and have an issue, at first stap we must get auth code with such request:
https://graph.facebook.com/oauth/authorize?client_id={your application id}&redirect_uri={site_uri}

We can get this code only after the authorization, but I need post to organization page directly from my site, without logging in facebook (I have app id and secret, can I write some request with this data and get code back without facebook auth form??)

Otherwise, I can get app access_token, but I can't post to organization page with this token (I have an error "The user hasn't authorized the application to perform this action"); but I can post to my (user) page with this token. Maybe I must get some permission to application for posting to org. page wall?? If yes, how can I do it??