Question

My app has 10 features that are enabled/disabled depending upon which of the 3 ‘types’ of account a user has.

Currently, I have 10 methods (one per feature) along the lines of:

def is_FEATURENAME_enabled
  case currentuser.accounttype
  when "A", "C"  # account types allow to see that feature
    return true
  else
    return false
  end
end

Then, in each place where I potentially disable a feature, I do

if foo.is_SOMEFEATURE_enable
   do stuff to enable that feature
end

It works. It’s not that hard to maintain. But there should be a better way. I suspect the right solution is to define some sort of structure (hash? I dunno) in one place that maps enabled features to accounttypes, then have a single method that I call something like:

if foo.is_feature_enabled(:FEATURENAME)
  do stuff to enable feature
end

where the method is_feature_enabled looks at currentuser.accountype and checks the mapping structure to see if the identified feature is enabled.

And I suspect the DRY way to define that mapping (given I have WAY more features than account types) is to list all the features ONCE then for each feature list the accounttypes that have access to that feature (not the other way around). That way when I add a new feature I only have to edit ONE line in the mapping. Something like:

FeatureA: usertype1
FeatureB: usertype1, usertype3
FeatureC: usertype2
...

seems more logical and easier to maintain than:

usertype1: FeatureA, FeatureB, FeatureD, FeatureG
usertype2: FeatureC, FeatureD
usertype3: FeatureB, FeatureD, FeatureG, FeatureH

Any suggestions would be appreciated, and instructive for learning The Right Way to do stuff in ruby.

Answer 1

I think you’ve pretty much discovered the best way to do it on your own– what you suggest is wise. Just use the feature name as a lookup key for your hash, then take the resulting list and check whether that list contains the account type of the current user.

E.g.,

# For example...
$AllowedUserCastes = {
 :CanLogin => ["admin", "paiduser", "crazyuser", "anonymous"],
 :CanDrink => ["admin", "21yearolduser", "crazyuser"],
 :CanArrest => ["admin", "police"]
}

def featureAllowed?( whichFeature )
    $AllowedUserCastes[whichFeature].include? currentUserCaste()
end