Class: Kongo::Model

Inherits:
Object
  • Object
show all
Defined in:
lib/kongo.rb

Overview

Kongo::Model is the most important class of Kongo, it wraps around hashes representing Mongo records, provides a collection of useful methods, and allows itself to be extended by third party libraries.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(hash, coll) ⇒ Model

Typically, you would not call Model#new directly, but rather get a model from a method on Collections, such as a finder or #insert.



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# File 'lib/kongo.rb', line 210

def initialize(hash, coll)
  @coll = coll
  @hash = hash
  @deltas = {}
  @visible_ivars = [:@hash, :@deltas]
  @@extensions ||= {}

  if @@extensions[coll.name.to_sym]
    @@extensions[coll.name.to_sym].each do |const|
      extend(const)
    end
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(key, *args, &block) ⇒ Object

This method_missing provides accessors for keys as proprieties of the model object, so you may do:

object.key = :value
object.key #=> :value



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# File 'lib/kongo.rb', line 295

def method_missing(key, *args, &block)
  key = key.to_s
  if matches = /^(.+)=$/.match(key)
    raise ArgumentError.new 'Unexpected argument count.' if args.count != 1
    self[matches[1]] = args.first
  else
    raise ArgumentError.new 'Unexpected argument count.' if args.count != 0
    return self[key]
  end
end

Instance Attribute Details

#deltas ⇒ Object (readonly)

Returns the value of attribute deltas.



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# File 'lib/kongo.rb', line 225

def deltas
  @deltas
end

#hash ⇒ Object (readonly)

Returns the value of attribute hash.



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# File 'lib/kongo.rb', line 224

def hash
  @hash
end

Class Method Details

.add_extension(collection_name, mod) ⇒ Object

Declare extensions using this method:

Kongo::Model.add_extension(:collection_name, module)



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# File 'lib/kongo.rb', line 369

def self.add_extension(collection_name, mod)
  ((@@extensions ||= {})[collection_name.to_sym] ||= []) << mod
end

Instance Method Details

#<=>(other) ⇒ Integer

Default comparison is via the string version of the id.

Examples:

Compare two models.

person <=> other_person

Parameters:

Returns:

  • (Integer) —

    -1, 0, 1.



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# File 'lib/kongo.rb', line 249

def <=>(other)
  self['_id'].to_s <=> other['_id'].to_s
end

#==(other) ⇒ true, false

Performs equality checking on the document ids.

Examples:

Compare for equality.

model == other

Parameters:

  • other (Kongo::Model, Object) —

    The other object to compare with.

Returns:

  • (true, false) —

    True if the ids are equal, false if not.



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# File 'lib/kongo.rb', line 262

def ==(other)
  self.class == other.class &&
    self['_id'] == other['_id']
end

#[](k) ⇒ Object

Record fields can be accessed using [] syntax.



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# File 'lib/kongo.rb', line 229

def [](k); @hash[k]; end

#[]=(k, v) ⇒ Object

This adds to the list of deltas, so that we may update with no arguments below



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# File 'lib/kongo.rb', line 234

def []=(k,v)
  @hash[k.to_s]=v

  delta('$set', k => v)
end

#delete! ⇒ Object

Deletes this record from the database.



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# File 'lib/kongo.rb', line 337

def delete!
  id = @hash['_id']
  raise unless id # TODO: custom exception
  @coll.remove({_id: id})
end

#delta(type, fields = {}) ⇒ Object

Add a delta

delta '$inc',
  total: 3,
  unique: 1



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# File 'lib/kongo.rb', line 273

def delta(type, fields = {})
  fields.each do |k,v|
    @deltas[type.to_s] ||= {}
    @deltas[type.to_s][k.to_s] = v
  end
  self
end

#extend(const) ⇒ Object

This method just adds the extension to the list of extension, for the sake of inspect, and call super:



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# File 'lib/kongo.rb', line 376

def extend(const)
  (@extensions ||= []) << const.to_s
  super
end

#inspect ⇒ Object

Inspecting a Mongo Model attempts to only show useful information, such as what its extensions are as well as certain ivars.



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# File 'lib/kongo.rb', line 352

def inspect
  proxy = Object.new
  @visible_ivars.each do |ivar|
    val = instance_variable_get(ivar)
    proxy.instance_variable_set(ivar, val) unless val.nil?
  end
  string = proxy.inspect
  ext_info = @extensions ? '(+ '+@extensions.join(', ')+')' : ''
  string.gsub(/Object:0x[0-9a-f]+/, "Kongo::Model#{ext_info}:0x#{object_id}")
end

#save!(options = {}) ⇒ Object

Deprecated.

Do not use saves, they’re dirty.



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# File 'lib/kongo.rb', line 309

def save!(options = {})
  warn("#{Kernel.caller.first}: `save` is deprecated, use `update` instead.")
  raise if @stale unless options[:ignore_stale] # TODO: custom exception
  @coll.save(@hash, :w => 1)
end

#to_hash ⇒ Object

Returns the hash of the record itself.



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# File 'lib/kongo.rb', line 345

def to_hash
  @hash
end

#unset(key) ⇒ Object

‘unset` lets you remove a key from the hash, as well as adding it to the deltas so that the next update will unset that key in Mongo.



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# File 'lib/kongo.rb', line 284

def unset(key)
  @hash.delete(key.to_s)
  delta('$unset', key => 1)
end

#update!(deltas = {}) ⇒ Object

Issues an update on the database, for this record, with the provided deltas. WARNING: the record will become stale, and should no longer be saved after an update has been issued.



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# File 'lib/kongo.rb', line 319

def update!(deltas = {})
  return if @deltas.empty? && deltas.empty?

  id = @hash['_id']
  raise unless id # TODO: custom exception

  if @deltas
    deltas = @deltas.merge(deltas)
    @deltas = {}
  end

  @stale = true

  @coll.update({_id: id}, deltas, :w => 1)
end