[Webkit-unassigned] [Bug 28825] New: Provide a WebView preference to disable DNS prefetching

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=28825

           Summary: Provide a WebView preference to disable DNS
                    prefetching
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Macintosh
        OS/Version: All
            Status: UNCONFIRMED
          Severity: Normal
          Priority: P2
         Component: WebKit API
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: opendarwin at lapcatsoftware.com


As far as I can tell, DNS prefetching is enabled by default in the WebKit
trunk, and there is no way to disable it. I'm looking at the trunk as of git
commit de240fc8d016a25d9f4b05f65195414375159b3c, corresponding to svn r47855.
At WebCore/dom/Document.cpp:4370 there is the following code:

    m_isDNSPrefetchEnabled = securityOrigin()->protocol() == "http";

So DNS prefetch appears to be on for any http document. I've verified this in
the debugger and via packet traces.

There should be a WebView preference to disable DNS prefetching. This could be
either part of WebPreferences or a direct accessor pair on WebView.

I've listed some concerns about DNS prefetching at
https://bugs.webkit.org/show_bug.cgi?id=20690#c4 and there are probably a
number of other concerns that I'm not even qualified to imagine. I believe that
item 2) is ok in the current implementation, but 1) and 3) still need to be
addressed. It's not clear whether 4) has been handled adequately -- it appears
that the DNS queue is limited to 64 requests, but I haven't tested how these
requests impact the system, especially with other internet apps running
simultanously, such as a syndicated feed reader. In any case, I think that
people would have very legitimate reasons for wanting to disable DNS
prefetching.

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.