Class: Sohm::Model

Inherits:
Object
  • Object
show all
Defined in:
lib/sohm.rb,
lib/sohm/json.rb

Overview

The base class for all your models. In order to better understand it, here is a semi-realtime explanation of the details involved when creating a User instance.

Example:

class User < Sohm::Model
  attribute :name
  index :name

  attribute :email
  unique :email

  counter :points

  set :posts, :Post
end

u = User.create(:name => "John", :email => "[email protected]")
u.incr :points
u.posts.add(Post.create)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(atts = {}) ⇒ Model

Initialize a model using a dictionary of attributes.

Example:

u = User.new(:name => "John")



916
917
918
919
920
921
 
# File 'lib/sohm.rb', line 916

def initialize(atts = {})
  @attributes = {}
  @serial_attributes = {}
  @serial_attributes_changed = false
  update_attributes(atts)
end

Instance Attribute Details

#cas_token ⇒ Object

Returns the value of attribute cas_token.



935
936
937
 
# File 'lib/sohm.rb', line 935

def cas_token
  @cas_token
end

#id ⇒ Object

Access the ID used to store this model. The ID is used together with the name of the class in order to form the Redis key.

Different from ohm, id must be provided by the user in sohm, if you want to use auto-generated id, you can include Sohm::AutoId module.

Raises:



929
930
931
932
 
# File 'lib/sohm.rb', line 929

def id
  raise MissingID if not defined?(@id)
  @id
end

Class Method Details

.[](id) ⇒ Object

Retrieve a record by ID.

Example:

u = User.create
u == User[u.id]
# =>  true



553
554
555
 
# File 'lib/sohm.rb', line 553

def self.[](id)
  new(:id => id).load! if id && exists?(id)
end

.attribute(name, cast = nil) ⇒ Object

The bread and butter macro of all models. Basically declares persisted attributes. All attributes are stored on the Redis hash.

class User < Sohm::Model
  attribute :name
end

user = User.new(name: "John")
user.name
# => "John"

user.name = "Jane"
user.name
# => "Jane"

A lambda can be passed as a second parameter to add typecasting support to the attribute.

class User < Sohm::Model
  attribute :age, ->(x) { x.to_i }
end

user = User.new(age: 100)

user.age
# => 100

user.age.kind_of?(Integer)
# => true

Check rubydoc.info/github/cyx/ohm-contrib#Ohm__DataTypes to see more examples about the typecasting feature.



811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
 
# File 'lib/sohm.rb', line 811

def self.attribute(name, cast = nil)
  if serial_attributes.include?(name)
    raise ArgumentError,
          "#{name} is already used as a serial attribute."
  end
  attributes << name unless attributes.include?(name)

  if cast
    define_method(name) do
      cast[@attributes[name]]
    end
  else
    define_method(name) do
      @attributes[name]
    end
  end

  define_method(:"#{name}=") do |value|
    @attributes[name] = value
  end
end

.collection(name, model, reference = to_reference) ⇒ Object

A macro for defining a method which basically does a find.

Example:

class Post < Sohm::Model
  reference :user, :User
end

class User < Sohm::Model
  collection :posts, :Post
end

# is the same as

class User < Sohm::Model
  def posts
    Post.find(:user_id => self.id)
  end
end



716
717
718
719
720
721
 
# File 'lib/sohm.rb', line 716

def self.collection(name, model, reference = to_reference)
  define_method name do
    model = Utils.const(self.class, model)
    model.find(:"#{reference}_id" => id)
  end
end

.counter(name) ⇒ Object

Declare a counter. All the counters are internally stored in a different Redis hash, independent from the one that stores the model attributes. Counters are updated with the ‘incr` and `decr` methods, which interact directly with Redis. Their value can’t be assigned as with regular attributes.

Example:

class User < Sohm::Model
  counter :points
end

u = User.create
u.incr :points

u.points
# => 1

Note: You can’t use counters until you save the model. If you try to do it, you’ll receive an Sohm::MissingID error.



883
884
885
886
887
888
889
890
891
 
# File 'lib/sohm.rb', line 883

def self.counter(name)
  counters << name unless counters.include?(name)

  define_method(name) do
    return 0 if new?

    redis.call("HGET", key[:_counters], name).to_i
  end
end

.create(atts = {}) ⇒ Object

Create a new model, notice that under Sohm’s circumstances, this is no longer a syntactic sugar for Model.new(atts).save



900
901
902
 
# File 'lib/sohm.rb', line 900

def self.create(atts = {})
  new(atts).save
end

.exists?(id) ⇒ Boolean

Check if the ID exists within <Model>:all.

Returns:

  • (Boolean) 


574
575
576
 
# File 'lib/sohm.rb', line 574

def self.exists?(id)
  redis.call("EXISTS", key[id]) == 1
end

.fetch(ids) ⇒ Object

Retrieve a set of models given an array of IDs.

Example:

User.fetch([1, 2, 3])



632
633
634
 
# File 'lib/sohm.rb', line 632

def self.fetch(ids)
  all.fetch(ids)
end

.find(dict) ⇒ Object

Find values in indexed fields.

Example:

class User < Sohm::Model
  attribute :email

  attribute :name
  index :name

  attribute :status
  index :status

  index :provider
  index :tag

  def provider
    email[/@(.*?).com/, 1]
  end

  def tag
    ["ruby", "python"]
  end
end

u = User.create(name: "John", status: "pending", email: "[email protected]")
User.find(provider: "me", name: "John", status: "pending").include?(u)
# => true

User.find(:tag => "ruby").include?(u)
# => true

User.find(:tag => "python").include?(u)
# => true

Due to restrictions in Codis, we only support single-index query. If you want to query based on multiple fields, you can make an index based on all the fields.



616
617
618
619
620
621
622
623
624
 
# File 'lib/sohm.rb', line 616

def self.find(dict)
  keys = filters(dict)

  if keys.size == 1
    Sohm::Set.new(keys.first, key, self)
  else
    raise NotSupported
  end
end

.index(attribute) ⇒ Object

Index any method on your model. Once you index a method, you can use it in ‘find` statements.



638
639
640
 
# File 'lib/sohm.rb', line 638

def self.index(attribute)
  indices << attribute unless indices.include?(attribute)
end

.key ⇒ Object

Returns the namespace for all the keys generated using this model.

Example:

class User < Sohm::Model
end

User.key == "User"
User.key.kind_of?(String)
# => true

User.key.kind_of?(Nido)
# => true

To find out more about Nido, see:

http://github.com/soveran/nido



541
542
543
 
# File 'lib/sohm.rb', line 541

def self.key
  Nido.new(self.name)
end

.list(name, model) ⇒ Object

Declare an Sohm::List with the given name.

Example:

class Comment < Sohm::Model
end

class Post < Sohm::Model
  list :comments, :Comment
end

p = Post.create
p.comments.push(Comment.create)
p.comments.unshift(Comment.create)
p.comments.size == 2
# => true

Note: You can’t use the list until you save the model. If you try to do it, you’ll receive an Sohm::MissingID error.



687
688
689
690
691
692
693
694
695
 
# File 'lib/sohm.rb', line 687

def self.list(name, model)
  track(name)

  define_method name do
    model = Utils.const(self.class, model)

    Sohm::List.new(key[name], model.key, model)
  end
end

.mutex ⇒ Object 



516
517
518
 
# File 'lib/sohm.rb', line 516

def self.mutex
  Sohm.mutex
end

.redis ⇒ Object 



502
503
504
 
# File 'lib/sohm.rb', line 502

def self.redis
  defined?(@redis) ? @redis : Sohm.redis
end

.redis=(redis) ⇒ Object 



498
499
500
 
# File 'lib/sohm.rb', line 498

def self.redis=(redis)
  @redis = redis
end

.reference(name, model) ⇒ Object

A macro for defining an attribute, an index, and an accessor for a given model.

Example:

class Post < Sohm::Model
  reference :user, :User
end

# It's the same as:

class Post < Sohm::Model
  attribute :user_id
  index :user_id

  def user
    User[user_id]
  end

  def user=(user)
    self.user_id = user.id
  end

  def user_id=(user_id)
    self.user_id = user_id
  end
end



751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
 
# File 'lib/sohm.rb', line 751

def self.reference(name, model)
  reader = :"#{name}_id"
  writer = :"#{name}_id="

  attributes << reader unless attributes.include?(reader)

  index reader

  define_method(reader) do
    @attributes[reader]
  end

  define_method(writer) do |value|
    @attributes[reader] = value
  end

  define_method(:"#{name}=") do |value|
    send(writer, value ? value.id : nil)
  end

  define_method(name) do
    model = Utils.const(self.class, model)
    model[send(reader)]
  end
end

.refresh_indices_inline ⇒ Object 



510
511
512
513
514
 
# File 'lib/sohm.rb', line 510

def self.refresh_indices_inline
  defined?(@refresh_indices_inline) ?
    @refresh_indices_inline :
    Sohm.refresh_indices_inline
end

.refresh_indices_inline=(refresh_indices_inline) ⇒ Object 



506
507
508
 
# File 'lib/sohm.rb', line 506

def self.refresh_indices_inline=(refresh_indices_inline)
  @refresh_indices_inline = refresh_indices_inline
end

.serial_attribute(name, cast = nil) ⇒ Object

Attributes that require CAS property



834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
 
# File 'lib/sohm.rb', line 834

def self.serial_attribute(name, cast = nil)
  if attributes.include?(name)
    raise ArgumentError,
          "#{name} is already used as a normal attribute."
  end
  serial_attributes << name unless serial_attributes.include?(name)

  if cast
    define_method(name) do
      # NOTE: This is a temporary solution, since we might use
      # composite objects (such as arrays), which won't always
      # do a reset
      @serial_attributes_changed = true
      cast[@serial_attributes[name]]
    end
  else
    define_method(name) do
      @serial_attributes_changed = true
      @serial_attributes[name]
    end
  end

  define_method(:"#{name}=") do |value|
    @serial_attributes_changed = true
    @serial_attributes[name] = value
  end
end

.set(name, model) ⇒ Object

Declare an Sohm::Set with the given name.

Example:

class User < Sohm::Model
  set :posts, :Post
end

u = User.create
u.posts.empty?
# => true

Note: You can’t use the set until you save the model. If you try to do it, you’ll receive an Sohm::MissingID error.



657
658
659
660
661
662
663
664
665
 
# File 'lib/sohm.rb', line 657

def self.set(name, model)
  track(name)

  define_method name do
    model = Utils.const(self.class, model)

    Sohm::MutableSet.new(key[name], model.key, model)
  end
end

.synchronize(&block) ⇒ Object 



520
521
522
 
# File 'lib/sohm.rb', line 520

def self.synchronize(&block)
  mutex.synchronize(&block)
end

.to_proc ⇒ Object

Retrieve a set of models given an array of IDs.

Example:

ids = [1, 2, 3]
ids.map(&User)

Note: The use of this should be a last resort for your actual application runtime, or for simply debugging in your console. If you care about performance, you should pipeline your reads. For more information checkout the implementation of Sohm::List#fetch.



569
570
571
 
# File 'lib/sohm.rb', line 569

def self.to_proc
  lambda { |id| self[id] }
end

.track(name) ⇒ Object

Keep track of ‘key` and remove when deleting the object.



894
895
896
 
# File 'lib/sohm.rb', line 894

def self.track(name)
  tracked << name unless tracked.include?(name)
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql?

Check for equality by doing the following assertions:

  1. That the passed model is of the same type.

  2. That they represent the same Redis key.



942
943
944
945
946
 
# File 'lib/sohm.rb', line 942

def ==(other)
  other.kind_of?(model) && other.key == key
rescue MissingID
  false
end

#attributes ⇒ Object

Returns a hash of the attributes with their names as keys and the values of the attributes as values. It doesn’t include the ID of the model.

Example:

class User < Sohm::Model
  attribute :name
end

u = User.create(:name => "John")
u.attributes
# => { :name => "John" }



1016
1017
1018
 
# File 'lib/sohm.rb', line 1016

def attributes
  @attributes
end

#counters ⇒ Object 



1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
 
# File 'lib/sohm.rb', line 1024

def counters
  hash = {}
  self.class.counters.each do |name|
    hash[name] = 0
  end
  return hash if new?
  redis.call("HGETALL", key[:_counters]).each_slice(2).each do |pair|
    hash[pair[0].to_sym] = pair[1].to_i
  end
  hash
end

#decr(att, count = 1) ⇒ Object

Decrement a counter atomically. Internally uses HINCRBY.



981
982
983
 
# File 'lib/sohm.rb', line 981

def decr(att, count = 1)
  incr(att, -count)
end

#delete ⇒ Object

Delete the model, including all the following keys:

  • <Model>:<id>

  • <Model>:<id>:_counters

  • <Model>:<id>:<set name>

If the model has uniques or indices, they’re also cleaned up.



1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
 
# File 'lib/sohm.rb', line 1166

def delete
  memo_key = key["_indices"]
  commands = [["DEL", key], ["DEL", memo_key], ["DEL", key["_counters"]]]
  index_list = redis.call("SMEMBERS", memo_key)
  index_list.each do |index_key|
    commands << ["SREM", index_key, id]
  end
  model.tracked.each do |tracked_key|
    commands << ["DEL", key[tracked_key]]
  end

  model.synchronize do
    commands.each do |command|
      redis.queue(*command)
    end
    redis.commit
  end

  return self
end

#hash ⇒ Object

Return a value that allows the use of models as hash keys.

Example:

h = {}

u = User.new

h[:u] = u
h[:u] == u
# => true



997
998
999
 
# File 'lib/sohm.rb', line 997

def hash
  new? ? super : key.hash
end

#incr(att, count = 1) ⇒ Object

Increment a counter atomically. Internally uses HINCRBY.



976
977
978
 
# File 'lib/sohm.rb', line 976

def incr(att, count = 1)
  redis.call("HINCRBY", key[:_counters], att, count)
end

#key ⇒ Object

Returns the namespace for the keys generated using this model. Check ‘Sohm::Model.key` documentation for more details.



906
907
908
 
# File 'lib/sohm.rb', line 906

def key
  model.key[id]
end

#load! ⇒ Object

Preload all the attributes of this model from Redis. Used internally by ‘Model::[]`.



950
951
952
953
954
 
# File 'lib/sohm.rb', line 950

def load!
  update_attributes(Utils.dict(redis.call("HGETALL", key))) if id
  @serial_attributes_changed = false
  return self
end

#new? ⇒ Boolean

Returns true if the model is not persisted. Otherwise, returns false.

Example:

class User < Sohm::Model
  attribute :name
end

u = User.new(:name => "John")
u.new?
# => true

u.save
u.new?
# => false

Returns:

  • (Boolean) 


971
972
973
 
# File 'lib/sohm.rb', line 971

def new?
  !(defined?(@id) && model.exists?(id))
end

#refresh_indices ⇒ Object

Refresh model indices



1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
 
# File 'lib/sohm.rb', line 1115

def refresh_indices
  memo_key = key["_indices"]
  # Add new indices first
  commands = fetch_indices.each_pair.map do |field, vals|
    vals.map do |val|
      index_key = model.key["_indices"][field][val]
      [["SADD", memo_key, index_key], ["SADD", index_key, id]]
    end
  end.flatten(2)

  model.synchronize do
    commands.each do |command|
      redis.queue(*command)
    end
    redis.commit
  end

  # Remove old indices
  index_set = ::Set.new(redis.call("SMEMBERS", memo_key))
  # Here we are fetching the latest model to avoid concurrency issue
  valid_list = model[id].send(:fetch_indices).each_pair.map do |field, vals|
    vals.map do |val|
      model.key["_indices"][field][val]
    end
  end.flatten(1)
  valid_set = ::Set.new(valid_list)
  diff_set = index_set - valid_set
  if diff_set.size > 0
    diff_list = diff_set.to_a
    commands = diff_list.map do |key|
      ["SREM", key, id]
    end + [["SREM", memo_key] + diff_list]

    model.synchronize do
      commands.each do |command|
        redis.queue(*command)
      end
      redis.commit
    end
  end
  true
end

#save ⇒ Object

Persist the model attributes and update indices and unique indices. The ‘counter`s and `set`s are not touched during save.

Example:

class User < Sohm::Model
  attribute :name
end

u = User.new(:name => "John").save
u.kind_of?(User)
# => true



1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
 
# File 'lib/sohm.rb', line 1085

def save
  if serial_attributes_changed
    response = script(LUA_SAVE, 1, key,
      sanitize_attributes(serial_attributes).to_msgpack,
      cas_token,
      sanitize_attributes(attributes).to_msgpack)

    if response.is_a?(RuntimeError)
      if response.message =~ /cas_error/
        raise CasViolation
      else
        raise response
      end
    end

    @cas_token = response
    @serial_attributes_changed = false
  else
    redis.call("HSET", key, "_ndata",
               sanitize_attributes(attributes).to_msgpack)
  end

  if model.refresh_indices_inline
    refresh_indices
  end

  return self
end

#script(file, *args) ⇒ Object

Run lua scripts and cache the sha in order to improve successive calls.



1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
 
# File 'lib/sohm.rb', line 1189

def script(file, *args)
  response = nil

  if Sohm.enable_evalsha
    response = redis.call("EVALSHA", LUA_SAVE_DIGEST, *args)
    if response.is_a?(RuntimeError)
      if response.message =~ /NOSCRIPT/
        response = nil
      end
    end
  end

  response ? response : redis.call("EVAL", LUA_SAVE, *args)
end

#serial_attributes ⇒ Object 



1020
1021
1022
 
# File 'lib/sohm.rb', line 1020

def serial_attributes
  @serial_attributes
end

#to_hash ⇒ Object

Export the ID of the model. The approach of Ohm is to whitelist public attributes, as opposed to exporting each (possibly sensitive) attribute.

Example:

class User < Sohm::Model
  attribute :name
end

u = User.create(:name => "John")
u.to_hash
# => { :id => "1" }

In order to add additional attributes, you can override ‘to_hash`:

class User < Sohm::Model
  attribute :name

  def to_hash
    super.merge(:name => name)
  end
end

u = User.create(:name => "John")
u.to_hash
# => { :id => "1", :name => "John" }



1064
1065
1066
1067
1068
1069
 
# File 'lib/sohm.rb', line 1064

def to_hash
  attrs = {}
  attrs[:id] = id unless new?

  return attrs
end

#to_json(*args) ⇒ Object

Export a JSON representation of the model by encoding ‘to_hash`.



6
7
8
 
# File 'lib/sohm/json.rb', line 6

def to_json(*args)
  to_hash.to_json(*args)
end

#update(attributes) ⇒ Object

Update the model attributes and call save.

Example:

User[1].update(:name => "John")

# It's the same as:

u = User[1]
u.update_attributes(:name => "John")
u.save



1216
1217
1218
1219
 
# File 'lib/sohm.rb', line 1216

def update(attributes)
  update_attributes(attributes)
  save
end

#update_attributes(atts) ⇒ Object

Write the dictionary of key-value pairs to the model.



1222
1223
1224
 
# File 'lib/sohm.rb', line 1222

def update_attributes(atts)
  unpack_attrs(atts).each { |att, val| send(:"#{att}=", val) }
end