Module: Ampere::Model::ClassMethods

Defined in:
lib/ampere/model.rb

Overview

Class methods

Instance Method Summary collapse

Instance Method Details

#all ⇒ Object

Returns a lazy collection of all the records that have been stored.



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# File 'lib/ampere/model.rb', line 203

def all
  Ampere::Collection.new(self, Ampere.connection.keys("#{to_s.downcase}.*"))
end

#belongs_to(field_name, options = {}) ⇒ Object

Declares a belongs_to relationship to another model.



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# File 'lib/ampere/model.rb', line 208

def belongs_to(field_name, options = {})
  has_one field_name, options
end

#compound_indices ⇒ Object

Like @indices, but only returns the compound indices this class defines.



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# File 'lib/ampere/model.rb', line 213

def compound_indices
  @indices.select{|i| i.class == Array}
end

#count ⇒ Object

Returns the number of instances of this record that have been stored.



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# File 'lib/ampere/model.rb', line 218

def count
  Ampere.connection.keys("#{to_s.downcase}.*").length
end

#create(hash = {}) ⇒ Object Also known as: create!

Instantiates and saves a new record.



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# File 'lib/ampere/model.rb', line 223

def create(hash = {})
  new(hash).save
end

#delete(id) ⇒ Object

Deletes the record with the given ID.



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# File 'lib/ampere/model.rb', line 229

def delete(id)
  record = find(id)
  Ampere.connection.del(key_for_find(self, id))
  record.destroyed = true
  record
end

#field(name, options = {}) ⇒ Object

Declares a field. See the README for more details.



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# File 'lib/ampere/model.rb', line 237

def field(name, options = {})
  @fields         ||= []
  @field_defaults ||= {}
  @indices        ||= []
  @unique_indices ||= []
  @field_types    ||= {}

  @fields << name

  # attr_accessor :"#{name}"

  # Handle default value
  @field_defaults[name] = options[:default]

  # Handle type, if any
  if options[:type] then
    @field_types[:"#{name}"] = options[:type].to_s
  end

  define_method :"#{name}" do
    instance_variable_get("@#{name}") or self.class.field_defaults[name]
  end

  define_method :"#{name}=" do |val|
    if not self.class.field_types[:"#{name}"] or val.is_a?(eval(self.class.field_types[:"#{name}"])) then
      instance_variable_set("@#{name}", val)
    else
      raise "Cannot set field of type #{self.class.field_types[name.to_sym]} with #{val.class} value"
    end
  end
end

#field_defaults ⇒ Object 



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# File 'lib/ampere/model.rb', line 273

def field_defaults
  @field_defaults
end

#field_types ⇒ Object 



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# File 'lib/ampere/model.rb', line 277

def field_types
  @field_types
end

#fields ⇒ Object 



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# File 'lib/ampere/model.rb', line 269

def fields
  @fields
end

#find(options = {}) ⇒ Object

Finds the record with the given ID, or the first that matches the given conditions



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# File 'lib/ampere/model.rb', line 282

def find(options = {})
  if options.class == String or options.is_a?(Fixnum) then
    options = key_for_find(self, options)
    
    if Ampere.connection.exists(options) then
      new(Ampere.connection.hgetall(options), true)
    else
      nil
    end
  else
    # TODO Write a handler for this case, even if it's an exception
    raise "Cannot find by #{options.class} yet"
  end
end

#first ⇒ Object 



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# File 'lib/ampere/model.rb', line 297

def first
  all.first
end

#has_many(field_name, options = {}) ⇒ Object

Defines a has_many relationship with another model. See the README for more details.



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# File 'lib/ampere/model.rb', line 323

def has_many(field_name, options = {})
  klass_name = (options[:class] or options['class'] or field_name.to_s.gsub(/s$/, ''))
  my_klass_name = to_s.downcase

  define_method(:"#{field_name}") do
    (Ampere.connection.smembers(key_for_has_many(my_klass_name, self.id, field_name))).map do |id|
      eval(klass_name.to_s.capitalize).find(id)
    end
  end

  define_method(:"#{field_name}=") do |val|
    val.each do |v|
      Ampere.connection.multi do
        Ampere.connection.sadd(key_for_has_many(my_klass_name, self.id, field_name), v.id)
        # Set pointer for belongs_to
        Ampere.connection.hset(key_for_find(v.class, v.id), "#{my_klass_name}_id", self.send("id"))
      end
    end
  end
end

#has_one(field_name, options = {}) ⇒ Object

Defines a has_one relationship with another model. See the README for more details.



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# File 'lib/ampere/model.rb', line 302

def has_one(field_name, options = {})
  referred_klass_name = (options[:class] or options['class'] or field_name)
  my_klass_name = to_s.downcase

  field :"#{field_name}_id"

  define_method(field_name.to_sym) do
    return if self.send("#{field_name}_id").nil?
    eval(referred_klass_name.to_s.capitalize).find(self.send("#{field_name}_id"))
  end

  define_method(:"#{field_name}=") do |val|
    return nil if val.nil?
    # Set attr with key where referred model is stored
    self.send("#{field_name}_id=", val.id)
    # Also update that model's hash with a pointer back to here
    val.send("#{my_klass_name}_id=", self.send("id")) if val.respond_to?("#{my_klass_name}_id=")
  end
end

#index(field_name, options = {}) ⇒ Object

Defines an index. See the README for more details.



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# File 'lib/ampere/model.rb', line 345

def index(field_name, options = {})
  # TODO There has just got to be a better way to handle this.
  @fields         ||= []
  @field_defaults ||= {}
  @indices        ||= []
  @unique_indices ||= []
  @field_types    ||= {}

  if field_name.class == String or field_name.class == Symbol then
    # Singular index
    raise "Can't index a nonexistent field!" unless @fields.include?(field_name)
  elsif field_name.class == Array then
    # Compound index
    field_name.each{|f| raise "Can't index a nonexistent field!" unless @fields.include?(f)}
    field_name.sort!
  else
    raise "Can't index a #{field_name.class}"
  end

  @indices << field_name
  @unique_indices << field_name if options[:unique]
end

#indices ⇒ Object 



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# File 'lib/ampere/model.rb', line 368

def indices
  @indices
end

#last ⇒ Object 



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# File 'lib/ampere/model.rb', line 372

def last
  all.last
end

#unique_indices ⇒ Object 



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# File 'lib/ampere/model.rb', line 376

def unique_indices
  @unique_indices
end

#where(options = {}) ⇒ Object

Finds an array of records which match the given conditions. This method is much faster when all the fields given are indexed.



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# File 'lib/ampere/model.rb', line 382

def where(options = {})
  if options.empty? then
    Ampere::Collection.new(eval(to_s), [])
  else
    indexed_fields    = (options.keys & @indices) + compound_indices_for(options)
    nonindexed_fields = (options.keys - @indices) - compound_indices_for(options).flatten
  
    results = nil
  
    unless indexed_fields.empty?
      indexed_fields.map {|key|
        if key.class == String or key.class == Symbol then
          Ampere.connection.hget(key_for_index(key), options[key]).split(/:/) #.map {|id| find(id)}
        else
          # Compound index
          Ampere.connection.hget(
            key_for_index(key.join(':')),
            key.map{|k| options[k]}.join(':')
          ).split(/:/) #.map {|id| find(id)}
        end
      }.each {|s|
        return s if s.empty?
    
        if results.nil? then
          results = s
        else
          results &= s
        end
      }
    end
    
    unless nonindexed_fields.empty?
      results = all if results.nil?
      results = results.to_a.map{|r| r.class == String ? find(r) : r}
      nonindexed_fields.each do |key|
        results.select!{|r| 
          r.send(key) == options[key]
        }
      end
    end
  
    # TODO The eval(to_s) trick seems a little... ghetto. 
    Ampere::Collection.new(eval(to_s), results.reverse)
  end
end