Caches etc
Caching of the actual page content
1 Cache on server
Parsed pages are cache on the database. If it is "fresh", then no parsing is needed and the cached page is returned.
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Private pages:
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index.html
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first ajax-request (pageLoad)
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Shall look the same (be cacheable (not include boARLoggedIn etc))
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no
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yes
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Public pages:
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index.html
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first ajax-request (getLoginBoolean)
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Shall look the same (be cacheable (not include boARLoggedIn etc))
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yes
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no
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For private pages, the potential ajax request is
private-cacheable (only stored in your computer/browser).
All cached requests of pages are
validated (The request looks like normal, only containing the header-field
if-modified-since and the server may answer with a short 304 (Not Modified))
3 Returning to a page during a session
If you return to a page during a session (regardless of what web app or web page you're surfing on), the web browser will not make a request (not even a validation request) of the page. This might cause a problem if you edit a page, goes forward, then hit back button, then you would get a stale page.
However with javascript you can change this behavior, and this is what's done if you have made any changes to the page.
This way hitting the backbutton will give very rapid (cached) response on pages that you have
not changed, but still get up to date (but a bit slower) responses to pages that you
have changed.
This behavior will however give you a
stale page if other people have changed the page.
Caching of static files (js, css, image-files for the interface etc.)
Static files have their sha1-hash calculated and added to their url in the index-file which means that no request needs to be done unless they have changed.
Also
ETag-header fields and 304 (Not Modified) are used.