Proposed changes for Mongomatic 0.9.0 (Jordan's Edits)

accessing_snapshot.rb

@snapshot = Snapshot.first
-----
{
  :stats => {
    'accounts' => { 'count' => 8, 'a' => 1 },
    'subscriptions' => { 'count' => 16, 'b' => 1 }
  },
  :activity => [ {'ns' => 'accounts.users', ...}, {'ns' => 'subscriptions.users' =>, ...} ] 
}
-----
# Attribute definitions would be defined as instance method accessors
# 
# For example:
#   def database_id; self.doc[:database_id]; end

@snapshot.database_id
@snapshot.created_at
@snapshot.stats

----
# select should always return an array even if it matches a single hash
@snapshot.select('stats.*', :count => 16) # => [{'count' => 16, 'b' => 1}]

# not sure which of the next two I prefer
@snapshot.select('stats.*') do |sub_hash|
  sub_hash['count'].to_i >= 8
end # => [{'count' => 8, 'a' => 1}, {'count' => 16, 'b' => 1}]

@snapshot.select('stats.*', count: ->(c) { c >= 8 }) # i think when you want to test more than one key, the first one will be cleaner

@snapshot.select('activity.*', :ns => /^accounts\.$/) # would return an array of sub-hashes that matches the query in the array

# if select always returns an array its a nice extension to allow you it iterate with each
@snapshot.each('activity.*', :ns => /^accounts\.$/) do |hash|
   # ...
end


-----
@snapshot['stats.accounts.count'] # => 8
@snapshot['stats.posts.count'] # => nil
@snapshot.doc(['stats.posts.count'], true|false) # => KeyDoesNotExist, 'stats.posts does not exist in the document hash, true is the default here as your assuming the hash exists at the doc level


# Assignment -- not sure about this one.
@snapshot['stats.posts.count'] = 8 # => {:stats => { 'posts' => { 'count' => 8 } } } but raise error if the type is an Array.

@snapshot['stats.*.count'] = 8 # => mass assignment to doc[:stats].each {|x| x[:count] = 8 }

game_object.rb

# Example of Modifier Chaining: Use multiple modifier methods (fastmods) in one update query
# Some things to address:
#    * do we raise errors or let mongo do it if you try to fastmod the same key twice in a chain
#    * are all the different interfaces needed (explicit, block, chain)? (see three examples)
#    * my first implementation of this made the update safe if a single mod! method was called in the chain
#      mongoo does this instead by having #start_modifier_chain and #start_modifier_chain! (its called something 
#      different in mongoo). 

class GameObject
   include Mongomatic
   include Montomatic::ModifierChain # not sure if we want this in a sep. module or not

   
   attribute :silver_amt, typed: Fixnum
   attribute :gold_amt, typed: Fixnum
   attribute :facebook_friends, typed: Array
   attribute :friends_total_animal_count, typed: Integer
   
   def inc_gold_and_silver(gold, silver)
      self.start_modifier_chain
      self.inc('gold', gold)
      self.inc('silver', silver)
      self.flush_modifier_chain
   end

   def add_friend(id, animal_count)
      self.start_modifier_chain do |game_obj| # this is more useful when working outside of instance methods and not using self
         game_obj.push('facebook_friends', id)
         game_obj.inc('friends_total_animal_count', animal_count)
      end
   end

   def buy_friends_animal(gold_cost)
     start_modifier_chain.inc('gold', 0 - gold_cost).inc('friends_total_animal_count', -1).flush_modifier_chain
   end
end

snapshot.rb

class Snapshot
  include Mongomatic # this will replace Mongomatic::Base, its like saying 'normal defaults'
  include Mongomatic::Sanitize

  attribute :database_id, :typed => Fixnum, :required => true
  attribute :created_at, :typed => Time, :required => true
  attribute :stats, :typed => Hash, :required => true

  sanitize_keys # will do the entire document
  sanitize_keys :stats, :replace_with => '#', :depth => 2 # various options we could support
  
  # class method to define indexes, it does not create the index on load, but says, if you call 
  # Snapshot.create_indexes I will create this index for you
  # same as: 
  # def create_indexes
  #    collection.ensure_index([['database_id', Mongo::ASCENDING], ['created_at', Mongo::DESCENDING]], :unique => true)
  # end
  #
  # still must pass array of arrays to "on" because no order preservation in 1.8 hashes
  # this does not create the index, it just says, if you call Snapshot.create_indexes
  # then it will be called
  index on: [['database_id', Mongo::Ascending], ['created_at', Mongo::DESCENDING]], opts: {unique: true}

end

I like the class level DSL, or a class method. This would not be evaluated on load of the class. Its more so we can do...

Note: @loaded_classes is a list of all the loaded classes defined in lets say Rails.root/app/models/*/

@loaded_classes.each { |class| class.ensure_indexes if class.respond_to?(:ensure_indexes) }

Which would make having a rake task & cap task easy for ensuring indexes. Also it also has a standard location for viewing indexes.