Class: MongoRecord::Base

Inherits:
Object show all
Defined in:
lib/mongo_record/base.rb

Overview

A superclass for database collection instances. The API is very similar to ActiveRecord. See #find for examples.

If you override initialize, make sure to call the superclass version, passing it the database row or hash that it was given.

Example:

class MP3Track < MongoRecord::Base
  collection_name :mp3_track
  fields :artist, :album, :song, :track
  def to_s
    "artist: #{self.artist}, album: #{self.album}, song: #{self.song}, track: #{track}"
  end
end

track = MP3Track.find_by_song('She Blinded Me With Science')
puts track.to_s

The database connection defaults to the global $db. You can set the connection using MongoRecord::Base.connection= and read it with MongoRecord::Base.connection.

# Set the connection to something besides $db
MongoRecord::Base.connection = connect('my-database')

Direct Known Subclasses

Subobject

Constant Summary collapse

@@connection = 
nil

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(row = {}) {|_self| ... } ⇒ Base

Initialize a new object with either a hash of values or a row returned from the database.

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/mongo_record/base.rb', line 717

def initialize(row={})
  case row
  when Hash
    row.each { |k, val|
      k = '_id' if k == 'id' # Rails helper
      init_ivar("@#{k}", val)
    }
  else
    row.instance_variables.each { |iv|
      init_ivar(iv, row.instance_variable_get(iv))
    }
  end
  # Default values for remaining fields
  (self.class.field_names + self.class.subobjects.keys).each { |iv|
    iv = "@#{iv}"
    instance_variable_set(iv, nil) unless instance_variable_defined?(iv)
  }
  self.class.arrays.keys.each { |iv|
    iv = "@#{iv}"
    instance_variable_set(iv, []) unless instance_variable_defined?(iv)
  }
  yield self if block_given?
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(sym, *args) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 848

def method_missing(sym, *args)
  if self.instance_variables.include?("@#{sym}")
    self.class.field(sym)
    return self.send(sym)
  else
    super
  end
end

Class Method Details

.all(*args) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 325

def all(*args)
  options = extract_options_from_args!(args)
  find_every(options)
end

.arrays ⇒ Object

Return the names of all instance variables that hold objects declared using has_many. The names do not start with ‘@’.



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# File 'lib/mongo_record/base.rb', line 158

def arrays; @arrays; end

.belongs_to(name, options = {}) ⇒ Object

Tells Mongo that this object belongs to another. A no-op.



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# File 'lib/mongo_record/base.rb', line 206

def belongs_to(name, options={})
end

.collection ⇒ Object

The collection object for this class, which will be different for every subclass of MongoRecord::Base.



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# File 'lib/mongo_record/base.rb', line 211

def collection
  connection.collection(@coll_name.to_s)
end

.collection_name(coll_name) ⇒ Object

Call this method to set the Mongo collection name for this class. The default value is the class name turned into lower_case_with_underscores.



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# File 'lib/mongo_record/base.rb', line 120

def collection_name(coll_name)
  @coll_name = coll_name
  field(:_id, :_ns, :_update)
end

.connection ⇒ Object

Return the database connection. The default value is # $db.



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# File 'lib/mongo_record/base.rb', line 90

def connection
  conn = @@connection || $db
  raise "connection not defined" unless conn
  conn
end

.connection=(val) ⇒ Object

Set the database connection. If the connection is set to nil, then $db will be used.



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# File 'lib/mongo_record/base.rb', line 98

def connection=(val)
  @@connection = val
  @@connection.pk_factory = PKFactory.new unless @@connection.pk_factory
end

.count(options = {}) ⇒ Object

Returns the number of matching records.



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# File 'lib/mongo_record/base.rb', line 348

def count(options={})
  criteria = criteria_from(options[:conditions],options[:criteria]).merge!(where_func(options[:where]))
  begin
    collection.count(criteria)
  rescue => ex
    if ex.to_s =~ /Error with count command.*ns missing/
      # Return 0 because we will graciously assume that we are being
      # called from a subclass that has been initialized properly, and
      # is therefore mentioned in the schema.
      0
    else
      raise ex
    end
  end
end

.create(values_hash) ⇒ Object

Creates, saves, and returns a new database object.



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# File 'lib/mongo_record/base.rb', line 403

def create(values_hash)
  object = self.new(values_hash)
  object.save
  object
end

.delete(id) ⇒ Object

Deletes the record with the given id from the collection.



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# File 'lib/mongo_record/base.rb', line 370

def delete(id)
  collection.remove({:_id => id})
end

.delete_all(conditions = nil) ⇒ Object

Deletes all records that match condition, which can be a Mongo-style hash or an ActiveRecord-like hash. Examples:

Person.destroy_all "name like '%fred%'   # SQL WHERE clause
Person.destroy_all ["name = ?", 'Fred']  # Rails condition
Person.destroy_all {:name => 'Fred'}     # Mongo hash



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# File 'lib/mongo_record/base.rb', line 398

def delete_all(conditions=nil)
  collection.remove(criteria_from(conditions))
end

.destroy(id) ⇒ Object

Load the object with id and delete it.



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# File 'lib/mongo_record/base.rb', line 376

def destroy(id)
  id.is_a?(Array) ? id.each { |oid| destroy(oid) } : find(id).destroy
end

.destroy_all(conditions = nil) ⇒ Object

Destroy all objects that match conditions. Warning: if conditions is nil, all records in the collection will be destroyed.



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# File 'lib/mongo_record/base.rb', line 389

def destroy_all(conditions = nil)
  find(:all, :conditions => conditions).each { |object| object.destroy }
end

.field(*fields) ⇒ Object Also known as: fields

Creates one or more collection fields. Each field will be saved to and loaded from the database. The fields named “_id” and “_ns” are automatically saved and loaded.

The method “field” is also called “fields”; you can use either one.



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# File 'lib/mongo_record/base.rb', line 130

def field(*fields)
  fields.each { |field|
    field = field.to_sym
    unless @field_names.include?(field)
      ivar_name = "@" + field.to_s
      define_method(field, lambda { instance_variable_get(ivar_name) })
      define_method("#{field}=".to_sym, lambda { |val| instance_variable_set(ivar_name, val) })
      define_method("#{field}?".to_sym, lambda {
                      val = instance_variable_get(ivar_name)
                      val != nil && (!val.kind_of?(String) || val != '')
                    })
      @field_names << field
    end
  }
end

.field_names ⇒ Object

Return the field names.



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# File 'lib/mongo_record/base.rb', line 148

def field_names; @field_names; end

.find(*args) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 292

def find(*args)        
  options = extract_options_from_args!(args)        
  options.symbolize_keys!
  case args.first
  when :first
    find_initial(options)
  when :all
    find_every(options)
  when :last
    find_last(options)
  else
    find_from_ids(args, options)
  end
end

.find_by_mql(mql) ⇒ Object Also known as: find_by_sql

Returns all records matching mql. Not yet implemented.



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# File 'lib/mongo_record/base.rb', line 342

def find_by_mql(mql)    # :nodoc:
  raise "not implemented"
end

.find_each(*args) ⇒ Object

Yields each record that was found by the find options. The find is performed by find.

Example:

Person.find_each(:conditions => "age > 21") do |person|
  person.party_all_night!
end



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# File 'lib/mongo_record/base.rb', line 316

def find_each(*args)        
  options = extract_options_from_args!(args)        
  options.symbolize_keys!
  find_every(options).each do |record|
    yield record 
  end
  self
end

.first(*args) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 330

def first(*args)
#        args = ([:first]<<args).flatten
  options = extract_options_from_args!(args)
  find_initial(options)
end

.has_and_belongs_to_many(name, options = {}) ⇒ Object

Tells Mongo that this object has and many belongs to another object. A no-op.



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# File 'lib/mongo_record/base.rb', line 202

def has_and_belongs_to_many(name, options={})
end

.has_many(name, options = {}) ⇒ Object

Tells Mongo about an array of subobjects (which need not be MongoRecord::Subobjects).

Options: :class_name - Name of the class of the subobject.



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# File 'lib/mongo_record/base.rb', line 188

def has_many(name, options={})
  name = name.to_sym
  unless @arrays[name]
    ivar_name = "@" + name.to_s
    define_method(name, lambda { instance_variable_get(ivar_name) })
    define_method("#{name}=".to_sym, lambda { |val| instance_variable_set(ivar_name, val) })
    define_method("#{name}?".to_sym, lambda { !instance_variable_get(ivar_name).empty? })
    klass_name = options[:class_name] || field_name_to_class_name(name)
    @arrays[name] = eval(klass_name)
  end
end

.has_one(name, options = {}) ⇒ Object

Tell Mongo about a subobject (which need not be a MongoRecord::Subobject).

Options: <code>:class_name<code> - Name of the class of the subobject.



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# File 'lib/mongo_record/base.rb', line 168

def has_one(name, options={})
  name = name.to_sym
  unless @subobjects[name]
    ivar_name = "@" + name.to_s
    define_method(name, lambda { instance_variable_get(ivar_name) })
    define_method("#{name}=".to_sym, lambda { |val| instance_variable_set(ivar_name, val) })
    define_method("#{name}?".to_sym, lambda {
                    val = instance_variable_get(ivar_name)
                    val != nil && (!val.kind_of?(String) || val != '')
                  })
    klass_name = options[:class_name] || field_name_to_class_name(name)
    @subobjects[name] = eval(klass_name)
  end
end

.inherited(subclass) ⇒ Object

Get ready to save information about subclass.



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# File 'lib/mongo_record/base.rb', line 110

def inherited(subclass)
  subclass.instance_variable_set("@coll_name", class_name_to_field_name(subclass.name)) # default name
  subclass.instance_variable_set("@field_names", []) # array of scalars names (symbols)
  subclass.instance_variable_set("@subobjects", {}) # key = name (symbol), value = class
  subclass.instance_variable_set("@arrays", {})     # key = name (symbol), value = class
end

.instantiate(row = {}) ⇒ Object

This method only exists so that MongoRecord::Base and ActiveRecord::Base can live side by side.



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# File 'lib/mongo_record/base.rb', line 105

def instantiate(row={})
  new(row)
end

.last(*args) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 336

def last(*args)
  options = extract_options_from_args!(args)
  find_last(options)
end

.method_missing(sym, *args) ⇒ Object

Handles find_* methods such as find_by_name, find_all_by_shoe_size, and find_or_create_by_name.



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# File 'lib/mongo_record/base.rb', line 434

def method_missing(sym, *args)
  if match = /^find_(all_by|by)_([_a-zA-Z]\w*)$/.match(sym.to_s)
    find_how_many = ($1 == 'all_by') ? :all : :first
    field_names = $2.split(/_and_/)
    super unless all_fields_exist?(field_names)
    search = search_from_names_and_values(field_names, args)
    self.find(find_how_many, {:conditions => search}, *args[field_names.length..-1])
  elsif match = /^find_or_(initialize|create)_by_([_a-zA-Z]\w*)$/.match(sym.to_s)
    create = $1 == 'create'
    field_names = $2.split(/_and_/)
    super unless all_fields_exist?(field_names)
    search = search_from_names_and_values(field_names, args)
    row = self.find(:first, {:conditions => search})
    return self.new(row) if row # found
    obj = self.new(search.merge(args[field_names.length] || {})) # new object using search and remainder of args
    obj.save if create
    obj
  else
    super
  end
end

.mongo_ivar_names ⇒ Object

Return the names of all fields, subobjects, and arrays.



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# File 'lib/mongo_record/base.rb', line 161

def mongo_ivar_names; @field_names + @subobjects.keys + @arrays.keys; end

.remove ⇒ Object

Deletes the record with the given id from the collection.



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# File 'lib/mongo_record/base.rb', line 373

def delete(id)
  collection.remove({:_id => id})
end

.subobjects ⇒ Object

Return the names of all instance variables that hold objects declared using has_one. The names do not start with ‘@’.

These are not necessarily MongoRecord::Subobject subclasses.



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# File 'lib/mongo_record/base.rb', line 154

def subobjects; @subobjects; end

.sum(column) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 364

def sum(column)
  x = self.find(:all, :select=>column)   
  x.map {|p1| p1.followers_count}.compact.sum
end

.update(id, attributes) ⇒ Object

Finds the record from the passed id, instantly saves it with the passed attributes (if the validation permits it), and returns it. If the save fails under validations, the unsaved object is still returned.

The arguments may also be given as arrays in which case the update method is called for each pair of id and attributes and an array of objects is returned.

>

Example of updating one record:

Person.update(15, {:user_name => 'Samuel', :group => 'expert'})

Example of updating multiple records:

people = { 1 => { "first_name" => "David" }, 2 => { "first_name" => "Jeremy"} }
Person.update(people.keys, people.values)



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# File 'lib/mongo_record/base.rb', line 421

def update(id, attributes)
  if id.is_a?(Array)
    i = -1
    id.collect { |id| i += 1; update(id, attributes[i]) }
  else
    object = find(id)
    object.update_attributes(attributes)
    object
  end
end

.update_all(updates, conditions = nil) ⇒ Object

Not yet implemented.



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# File 'lib/mongo_record/base.rb', line 381

def update_all(updates, conditions = nil)
  # TODO
  raise "not yet implemented"
end

Instance Method Details

#==(comparison_object) ⇒ Object

Return true if the comparison_object is the same object, or is of the same type and has the same id.



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# File 'lib/mongo_record/base.rb', line 749

def ==(comparison_object)
  comparison_object.equal?(self) ||
    (comparison_object.instance_of?(self.class) &&
     comparison_object.id == id &&
     !comparison_object.new_record?)
end

#[](attr_name) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 839

def [](attr_name)
  self.send(attr_name)
end

#[]=(attr_name, value) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 843

def []=(attr_name, value)
  self.class.field(attr_name)
  self.send(attr_name.to_s + '=', value)
end

#attributes_from_column_definition ⇒ Object

Does nothing.



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# File 'lib/mongo_record/base.rb', line 890

def attributes_from_column_definition; end

#create ⇒ Object

Save self to the database and set the id.



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# File 'lib/mongo_record/base.rb', line 804

def create
  create_date = self.instance_variable_defined?("@created_at") ? self.created_at : nil
  set_create_times(create_date)
  with_id = self.class.collection.insert(to_mongo_value)
  @_id = with_id['_id'] || with_id[:_id]
  with_id
end

#delete ⇒ Object Also known as: remove

Remove self from the database and set @_id to nil. If self has no @_id, does nothing.



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# File 'lib/mongo_record/base.rb', line 825

def delete
  if @_id
    self.class.collection.remove({:_id => self._id})
    @_id = nil
  end
end

#destroy ⇒ Object

Delete and freeze self.



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# File 'lib/mongo_record/base.rb', line 834

def destroy
  delete
  freeze
end

#eql?(comparison_object) ⇒ Boolean

Delegate to ==

Returns:

  • (Boolean) 


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# File 'lib/mongo_record/base.rb', line 757

def eql?(comparison_object)
  self == (comparison_object)
end

#hash ⇒ Object

Delegate to id in order to allow two records of the same type and id to work with something like:

[ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]



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# File 'lib/mongo_record/base.rb', line 763

def hash
  id.hash
end

#id ⇒ Object

Return this object’s id.



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# File 'lib/mongo_record/base.rb', line 745

def id; @_id ? @_id.to_s : nil; end

#id=(val) ⇒ Object

Set the id of this object. Normally not called by user code.



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# File 'lib/mongo_record/base.rb', line 742

def id=(val); @_id = (val == '' ? nil : val); end

#new_record? ⇒ Boolean

Return true if this object is new—that is, does not yet have an id.

Returns:

  • (Boolean) 


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# File 'lib/mongo_record/base.rb', line 784

def new_record?
  @_id.nil? || self.class.collection.find_first("_id" => @_id).nil?
end

#save ⇒ Object

Save self and returns true if the save was successful, false if not.



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# File 'lib/mongo_record/base.rb', line 773

def save
  create_or_update      
end

#save! ⇒ Object

Save self and returns true if the save was successful and raises RecordNotSaved if not.



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# File 'lib/mongo_record/base.rb', line 779

def save!
  create_or_update || raise(RecordNotSaved)
end

#set_create_times(t = nil) ⇒ Object 



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# File 'lib/mongo_record/base.rb', line 894

def set_create_times(t=nil)
  t ||= Time.now
  t = Time.parse(t) if t.is_a?(String)
  self["created_at"] = t
  self["created_on"] = Time.local(t.year, t.month, t.day)
  self.class.subobjects.keys.each { |iv|
    val = instance_variable_get("@#{iv}")
    val.send(:set_create_times, t) if val
  }
end

#to_mongo_value ⇒ Object

Convert this object to a Mongo value suitable for saving to the database.



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# File 'lib/mongo_record/base.rb', line 790

def to_mongo_value
  h = {}
#      self.class.mongo_ivar_names.each {|iv| h[iv] = instance_variable_get("@#{iv}").to_mongo_value }
  mongo_values = self.instance_values
  # If the "_id" value is not set but an "id" value is, set "_id" equal to "id"
  if mongo_values["_id"].nil? && !mongo_values["id"].nil?
    mongo_values["_id"] = mongo_values["id"]
  end
  key_names = mongo_values.keys + self.class.subobjects.keys + self.class.arrays.keys
  key_names.each {|key| h[key] = instance_variable_get("@#{key}").to_mongo_value }
  h
end

#to_param ⇒ Object

Rails convenience method. Return this object’s id as a string.



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# File 'lib/mongo_record/base.rb', line 768

def to_param
  @_id.to_s
end

#update ⇒ Object

Save self to the database. Return false if there was an error, self if all is well.



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# File 'lib/mongo_record/base.rb', line 814

def update
  set_update_times
  self.class.collection.modify({:_id => @_id}, to_mongo_value)
  if self.class.collection.db.error?
    return false
  end
  self      
end

#update_attribute(name, value) ⇒ Object

Updates a single attribute and saves the record. This is especially useful for boolean flags on existing records. Note: This method is overwritten by the Validation module that’ll make sure that updates made with this method doesn’t get subjected to validation checks. Hence, attributes can be updated even if the full object isn’t valid.



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# File 'lib/mongo_record/base.rb', line 868

def update_attribute(name, value)
  self[name] = value
  save
end

#update_attributes(attributes) ⇒ Object

Updates all the attributes from the passed-in Hash and saves the record. If the object is invalid, the saving will fail and false will be returned.



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# File 'lib/mongo_record/base.rb', line 876

def update_attributes(attributes)
  attributes.each do |name, value|
    update_attribute(name, value)
  end
end

#update_attributes!(attributes) ⇒ Object

Updates an object just like Base.update_attributes but calls save! instead of save so an exception is raised if the record is invalid.



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# File 'lib/mongo_record/base.rb', line 884

def update_attributes!(attributes)
  self.attributes = attributes
  save!
end