Class: DatastaxRails::DynamicModel

Inherits:
WideStorageModel show all
Defined in:
lib/datastax_rails/dynamic_model.rb

Overview

An extension to Wide Storage Models that let you index any arbitrary field that you want (given certain naming conventions).

Try to keep the group_by as sort as possible since it will get stored with every attribute. Static attributes are only supported if they are included on every dynamic model that uses the same column family.

Dynamic models have the following attributes:

  • strings

  • texts

  • booleans

  • dates

  • timestamps

  • integers

  • floats

  • uuids

Each of these is a map that let’s you store key/value pairs where the key is always a String and the value is a type that matches what would be stored in a static attribute of the same time. Everything will get typecasted, so you can safely store strings in it in all the same cases that you store strings in normal attributes.

The advantage here is that you don’t have to pre-define your schema ahead of time. The keys of any attributes added to this collection become fields in your Solr document.

NOTE: due to the way fields dynamically map between Solr and Cassandra, the field name in Solr will have a prefix prepended to it. With the exception of timestamps, it is simply the first letter of the type followed by an underscore (_). So s_ for strings. Timestamp has a ts_ prefix to differentiate it from texts.

class Item < DatastaxRails::DynamicModel
  self.grouping = 'item'
  timestamps
end

class CoreMetadata < DatastaxRails::DynamicModel
  self.grouping = 'core'
  timestamps
end

class TeamMetadata < DatastaxRails::DynamicModel
  self.grouping = 'team'
  timestamps
end

item = Item.create(strings: {title: "Title"})
CoreMetadata.create(id: item.id, strings: {author: 'John'}, dates: {published_on: Date.today})
TeamMetadata.create(id: item.id, booleans: {reviewed: true})

CoreMetadata.where(s_author: 'John') #=> Finds the CoreMetadata record
Item.fulltext("Title") #=> Finds the Item record
Item.fulltext("John") #=> Doesn't find a record, but...
Item.fulltext("{!join from=id to=id}John") #=> Does find the record by doing a Solr join across the entire row

NOTE that the mapping of key names is happening automatically when you insert something into the collection so:

Item.first.strings #=> {s_title: "Title"}

If you would like to still define known attributes ahead of time, you can still do so:

class TeamMetadata < DatastaxRails::DynamicModel
  self.grouping = 'team'
  string :name
  timestamps
end

TeamMetadata.new(name: 'John').name #=> 'John'
TeamMetadata.new(name: 'John').strings #=> {'s_name' => 'John'}

Getters and setters are automatically created to map to the attribute stored in the hash. In addition, there is a helper method to map column names to the field name in solr to assist with search.

Constant Summary collapse

PREFIXES = 
{ string: :s_, text: :t_, boolean: :b_, date: :d_, long: :l_, double: :db_,
timestamp: :ts_, integer: :i_, float: :f_, uuid: :u_ }.with_indifferent_access

Constants included from Callbacks

Callbacks::CALLBACKS

Instance Attribute Summary

Attributes inherited from Base

#attributes, #key, #loaded_attributes

Attributes included from AutosaveAssociation

#destroyed_by_association, #marked_for_destruction

Attributes included from Associations

#association_cache

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from WideStorageModel

#id_for_update

Methods inherited from Base

#==, attribute_names, #attribute_names, base_class, #column_names, columns, default_page_size, #eql?, find_by_id, #freeze, #frozen?, #hash, #init_changed_attributes, #init_internals, #init_with, #initialize, #inspect, inspect, logger, models, payload_model?, search_ids, #to_param, valid_consistency?, #valid_consistency?, wide_storage_model?

Methods included from SolrRepair

#repair_solr

Methods included from Serialization

#serializable_hash, #to_xml

Methods included from Timestamps

#initialize_dup

Methods included from Scoping

#populate_with_current_scope_attributes

Methods included from AutosaveAssociation

#changed_for_autosave?, #mark_for_destruction, #reload

Methods included from Associations

#association, #clear_association_cache

Methods included from Callbacks

#destroy

Methods included from Validations

#save, #save!, #valid?

Methods included from AttributeMethods

#attribute_exists?, #attribute_for_inspect, #column_for_attribute, #method_missing, #respond_to?

Methods included from AttributeAssignment

#assign_attributes

Methods included from Batches

#find_each, #find_each_with_index, #find_in_batches

Methods included from FinderMethods

#find, #find_by, #find_by!, #first, #first!, #last, #last!

Methods included from Persistence

#destroy, #persisted?, #reload, #save, #save!, #toggle, #toggle!, #update_attribute, #update_attributes, #update_attributes!

Constructor Details

This class inherits a constructor from DatastaxRails::Base

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class DatastaxRails::AttributeMethods

Class Method Details

._attribute ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 94

alias_method :_attribute, :attribute

.attribute(name, options) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 96

def attribute(name, options)
  options.symbolize_keys!
  unless [:map, :list, :set].include?(options[:type].to_sym)
    # Only type supported for now
    options.assert_valid_keys(:type)
    unless PREFIXES.key?(options[:type])
      fail(ArgumentError, "Invalid type specified for dynamic attribute: '#{name}: #{options[:type]}'")
    end
    virtual_attributes[name.to_s] = PREFIXES[options[:type]].to_s + name.to_s
  end
  super
end

.grouping=(group) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 88

def grouping=(group)
  self.group_by_attribute = group
  attribute_definitions['group'].default = group
  default_scope -> { where('group' => group) }
end

.inherited(child) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 109

def inherited(child)
  super
  child.virtual_attributes =
    child.virtual_attributes.nil? ? {}.with_indifferent_access : child.virtual_attributes.dup
  child.column_family = 'dynamic_model'
  child.primary_key = 'id'
  child.cluster_by = 'group'
  child._attribute :id, type: :uuid
  child._attribute :group, type: :string
  PREFIXES.each do |k, v|
    child._attribute v, holds: k.to_sym, type: :map
    child.instance_eval { alias_attribute k.to_s.pluralize, v }
  end
end

.solr_field_name(attr, type = nil) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 124

def solr_field_name(attr, type = nil)
  type ||= attribute_definitions[attr].try(:type)
  fail(UnknownAttributeError, 'Collections cannot be mapped') if [:map, :list, :set].include?(type)
  fail(UnknownAttributeError, "Unknown attribute: #{attr}. You must specify a type.") unless type
  PREFIXES[type].to_s + attr.to_s
end

Instance Method Details

#read_attribute(attr_name) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 141

def read_attribute(attr_name)
  if virtual_attributes.include?(attr_name.to_s)
    type = self.class.attribute_definitions[attr_name].type
    send(PREFIXES[type])[attr_name]
  else
    super
  end
end

#solr_field_name(attr, type = nil) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 150

def solr_field_name(attr, type = nil)
  self.class.solr_field_name(attr, type)
end

#write_attribute(attr_name, val) ⇒ Object 



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# File 'lib/datastax_rails/dynamic_model.rb', line 132

def write_attribute(attr_name, val)
  if virtual_attributes.include?(attr_name.to_s)
    type = self.class.attribute_definitions[attr_name].type
    send(PREFIXES[type])[attr_name] = val
  else
    super
  end
end