NEWS/InternalStructure

You can summarise any NEWS request down to four possibilities.

• Request a page to view
• Request a page to edit
• Preview an edited page
• Save an edited page

So, let's elaborate the stages NEWS goes through for each.

Request to view

1. Security layer checks access permissions of user requesting (via cookies)
2. Security layer checks view permissions of page requested (via 'page i/o' module)
3. Translation layer fetches the page from i/o and renders it to html
4. page is returned to user.

Request to Edit

1. Security checks user permissions
2. Security checks edit permissions of page
   1. If edit is OK, then Translator fetches page and renders it to an edit form
   2. If edit is not OK, but view is OK, then Translator fetches the page and renders it to 'view raw source'
3. page is returned to user

Preview/save an edit

1. Security checks user perms and edit perms of the page
   1. If edit is OK then feed to Translator which checks for concurrent edits.
      1. If no concurrent edits, then render the page as page, and ALSO as edit form. (or save page if saving rather than previewing)
      2. If concurrent editing has occured, then render the new page, show diffs, and show current edited version as edit form.
   2. If edit is not OK, but view is OK, then Translator renders the changes as 'view raw source', but no further editing.
2. page is returned to user