NEW 27971
Externally referenced fonts break with back button due to aggressive protection 
https://bugs.webkit.org/show_bug.cgi?id=27971
Summary Externally referenced fonts break with back button due to aggressive protection
ianh
Reported 2009-08-04 00:08:50 PDT
Steps to reproduce, on WebKit r46711: * Go to http://www.typotheque.com/webfonts/sample. Note the pretty typefaces. * Click on a link, e.g. "This is how this page should look like." * Press the back button. Note how everything is in Times now. There is some kind of referrer validation on the font resources (probably an attempt to prevent font theft). The cause of this bug may be an incorrect referrer when fetching these resources.
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Alexey Proskuryakov
Comment 1 2009-08-06 18:17:46 PDT
We do send a correct Referer on Back. The problem here is that the page references a CSS file that's different on each reload, and it has one-time URLs for fonts. I.e., each URL can only be used once, then it becomes "Not found". On Back, we don't reload the CSS, but try to reload fonts using original URLs. This happens because the page is in page cache, so neither it nor its stylesheets are reloaded on Back. But fonts (and probably other subresources) are re-requested from WebCore memory cache, which in turn tries to revalidate from network, due at all those no-cache and must-revalidate pragmas sent with original response.
Alexey Proskuryakov
Comment 2 2009-08-06 18:19:17 PDT
Note that this is also a performance problem, not just something that breaks this particular kind of DRM.
Alexey Proskuryakov
Comment 3 2009-08-06 18:21:06 PDT
<rdar://problem/7125277>
Alexey Proskuryakov
Comment 4 2011-12-07 09:08:36 PST
The test no longer fails for me. However, I still see in Web Inspector that we re-request fonts on Back.
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