[pmwiki-devel] File Locking?

[Patrick R. Michaud]

On Tue, Oct 30, 2007 at 02:07:48AM -0400, Stirling Westrup wrote:
> What's the correct way to use PmWiki's Lock() function? I couldn't find any
> documentation on it.
> 
> I have an application where someone might post a form that creates a blog
> entry. The blog group contains blog entries with sequential numerical names.
> Once someone hits 'post', the process I have is:
> 
> 1) determine the current highest existing page name in the group.
> 2) increment the highest page name to create a new name.
> 3) create a new page with that name, and write the information to it.
> 
> Now, if two people are posting entries simultaneously, they may choose to use
> the same new page name, and overwrite each other's additions. I would like to
> avoid that. Is there some way to use Lock to prevent them stepping on each
> other's toes?

At the point where you're determining the current highest existing page
name in the group, call Lock(2) .  This will prevent any other PmWiki
process from updating or saving pages until after the current process
has finished (or Lock(0) is called).

Pm