[pmwiki-users] MD5 checksums or version control (was: Re: Avoiding simultaneous edits)

Patrick R. Michaud pmichaud at pobox.com
Wed Sep 20 14:07:34 CDT 2006

On Wed, Sep 20, 2006 at 02:46:29PM -0400, Neil Herber wrote:
> At 2006-09-20  12:56 PM -0500, Patrick R. Michaud is rumored to have said:
> >I just haven't figured out the substitution markup that makes
> >sense for this.  I can envision doing one of:
> >
> >    Attach:foo.txt"%md5 %size"
> >    Attach:foo.txt"$md5 $size"
> >    Attach:foo.txt"{md5} {size}"
> For my money, Attach:foo.txt"{md5} {size}" makes the most sense and 
> is the most readable.  [...]
> I seem to remember that curly braces were difficult to type on German 
> keyboards, which may make this a less popular choice in some circles.

It's okay if uncommon markups are somewhat difficult to type on
some keyboards.  

> Not sure how the MD5 would be created (upon saving the page?, 
> uploaded by the user?) because some of the files I have online are 20 
> megs, and calculating an MD5 on-the-fly would seem to be a colossal 
> waste of cycles.

Hmm, I hadn't thought about the costs of generating md5's on
large files.  And I don't know of a convenient place to store it. 
And even if we have a place to store the md5, it'd then be a 
pain to try to keep the two synchronized.  :-(

It may be that {md5} will be available but could be left as
being expensive for large attachments [...] at least until we can
come up with a better answer.  It may be that pages get an
"attachment list" attribute, in which case the md5's could 
potentially be cached there.


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