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POrails - implementing a simple lock to prevent user's from editing the same data concurrently
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copied!<p>I have an app where I need to prevent users from editing data while it is being edited by a different user. I'm trying to think of the best way to do it and wanted to ask for ideas. So far, I've created a settings model that stores application wide configuration on the db in key/value pairs. So, for the lock, I have a settings instance that's called LOCKED_TABLE_UID, and it stored the user_id of the user editing the table or null (nil) if the table is free.</p> <pre><code>>> lock = Setting.find_by_key('LOCKED_TABLE_UID') </code></pre> <p>Then, I implemented 2 methods in my application controller to acquire and release the lock:</p> <pre><code># current_user returns the user currently logged in def acquire_lock lock = Setting.find_by_key("LOCKED_TABLE_UID") if lock.value # if lock taken, see if it's the current_user or someone else if lock.value.to_i == current_user.id.to_i return true else return false end else # lock is free, assign it to this user lock.value = current_user.id return true if lock.save end end def release_lock lock = Setting.find_by_key("LOCKED_TABLE_UID") if lock.value # the lock belongs to current_user, so he can release it if lock.value.to_i == current_user.id.to_i lock.value = nil return true if lock.save else # not your lock, go away return false end else # lock is free, quit bugging return true end end </code></pre> <p>What I want is to create some kind of block code that contains the locking mechanism, something like this:</p> <pre><code>def some_crud_action requires_locking do |lock| if lock # do some CRUD stuff here else # decline CRUD and give some error end end end </code></pre> <p>I'd appreciate help on this - but I'm also open to other suggestions on how to accomplish all that, or some things I may have overlooked. This lock doesn't have to be atomic, but fairly basic and most important - that it works :) thanks.</p>

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