title: How can I check if current user has write access to a specific field in TYPO3
body: <p>I would like to check if the current BE user has access to a specific field, e.g. pages.canonical_link or tt_content.header_link. </p>
  
  <p>I can see how this can be done by checking for the permissions of current user to edit the page or content by using e.g. <code>$GLOBALS['BE_USER']-&gt;getPagePermsClause(Permission::CONTENT_EDIT)</code>. Also it can be checked if user has write access to table by accessing via <code>$GLOBALS['BE_USER']-&gt;groupData['tables_modify']</code> or to the field by checking if the field is an exclude field and checking <code>groupData['non_exclude_fields']</code>.</p>
  
  <p>But groupData is public but internal (so this generates warnings) and I am wondering if maybe I am missing some more <strong>general public API</strong> to do this. Also, I am not sure if I am missing some things: There are a lot of ways you can configure the access, such as editlock for the page, you can restrict access to edit fields for specific language, etc. etc.</p>