Module: MiniModel

Defined in:
lib/mini_model.rb

Defined Under Namespace

Modules: ClassMethods Classes: Error, MissingId

Constant Summary collapse

VERSION = 
'0.0.2'

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(model) ⇒ Object 



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# File 'lib/mini_model.rb', line 8

def self.included(model)
  model.extend(ClassMethods)
end

Instance Method Details

#==(other) ⇒ Object

Strap in, the is probably the most complicated method in the entire library.



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# File 'lib/mini_model.rb', line 169

def ==(other)
  # If the classes don't match, they cannot possibly be equal.
  if self.class != other.class
    return false
  end

  # If the persisted state doesn't match, they also can never be equal.
  if persisted? != other.persisted?
    return false
  end

  # When persisted, check the other's id to see if it's the same,
  # cannot possible be equals if they have different ids.
  if persisted? && id != other.id
    return false
  end

  # Finally, compare the attributes hash. If all key/values match,
  # they are considered equal.
  attributes == other.attributes
end

#attributes ⇒ Object 



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# File 'lib/mini_model.rb', line 148

def attributes
  @attributes
end

#attributes=(attributes) ⇒ Object

#attributes= is vulnerable to mass assignment attacks if used directly with user input. Some sort of filter must be in place before setting attributes or initializing a new model.



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# File 'lib/mini_model.rb', line 155

def attributes=(attributes)
  @attributes = {}

  attributes.each do |key, value|
    writer = :"#{key}="

    if respond_to?(writer)
      send(writer, value)
    end
  end
end

#create ⇒ Object

#create (as well as #update, and #delete) return self on success and nil on failure. This lets us use these actions as if conditions which is convenience though dangerous.



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# File 'lib/mini_model.rb', line 209

def create
  id = dataset.insert(attributes)

  if id
    self.id = id

    self
  else
    nil
  end
end

#dataset ⇒ Object 



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# File 'lib/mini_model.rb', line 129

def dataset
  self.class.dataset
end

#delete ⇒ Object 



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# File 'lib/mini_model.rb', line 231

def delete
  count = dataset.where(id: id).delete

  if count.to_i > 0
    self.id = nil

    self
  else
    nil
  end
end

#id ⇒ Object 



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# File 'lib/mini_model.rb', line 133

def id
  if @id
    @id
  else
    # If our model does not have an id, raise at the first occurence
    # of anyone expecting it. This prevents us from assigning associations
    # and other logical paths for things that do not exist in the db.
    raise MissingId
  end
end

#id=(id) ⇒ Object 



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# File 'lib/mini_model.rb', line 144

def id=(id)
  @id = id
end

#initialize(attributes = {}) ⇒ Object 



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# File 'lib/mini_model.rb', line 125

def initialize(attributes = {})
  self.attributes = attributes # Will set the id if it exists.
end

#persisted? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mini_model.rb', line 191

def persisted?
  !!@id
end

#save ⇒ Object

Use #save to write generic persistence code in things like form objects so you don’t have to reach inside the model to determine the proper method to call.



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# File 'lib/mini_model.rb', line 198

def save
  if persisted?
    update
  else
    create
  end
end

#update ⇒ Object 



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# File 'lib/mini_model.rb', line 221

def update
  count = dataset.where(id: id).update(attributes)

  if count.to_i > 0
    self
  else
    nil
  end
end