Class: Gcloud::Datastore::Entity

Inherits:
Object
  • Object
show all
Defined in:
lib/gcloud/datastore/entity.rb

Overview

# Entity

Entity represents a Datastore record. Every Entity has a Key, and a list of properties.

Examples:

entity = Gcloud::Datastore::Entity.new
entity.key = Gcloud::Datastore::Key.new "User", "[email protected]"
entity["name"] = "Heidi Henderson"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Entity

Create a new Entity object.



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# File 'lib/gcloud/datastore/entity.rb', line 40

def initialize
  @properties = Properties.new
  @key = Key.new
  @_exclude_indexes = {}
end

Instance Attribute Details

#key ⇒ Object

The Key that identifies the entity.



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# File 'lib/gcloud/datastore/entity.rb', line 36

def key
  @key
end

#properties ⇒ Gcloud::Datastore::Properties (readonly)

Retrieve properties in a hash-like structure. Properties can be accessed or set by string or symbol.

Examples:

entity.properties[:name] = "Heidi H. Henderson"
entity.properties["name"] #=> "Heidi H. Henderson"

entity.properties.each do |name, value|
  puts "property #{name} has a value of #{value}"
end

A property’s existence can be determined by calling exist?:

entity.properties.exist? :name #=> true
entity.properties.exist? "name" #=> true
entity.properties.exist? :expiration #=> false

A property can be removed from the entity:

entity.properties.delete :name
entity.save

The properties can be converted to a hash:

prop_hash = entity.properties.to_h

Returns:



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# File 'lib/gcloud/datastore/entity.rb', line 151

def properties
  @properties
end

Class Method Details

.from_proto(proto) ⇒ Object 



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# File 'lib/gcloud/datastore/entity.rb', line 303

def self.from_proto proto
  entity = Entity.new
  entity.key = Key.from_proto proto.key
  Array(proto.property).each do |p|
    entity[p.name] = Proto.from_proto_value p.value
  end
  entity.send :update_exclude_indexes!, proto
  entity
end

Instance Method Details

#[](prop_name) ⇒ Object?

Retrieve a property value by providing the name.

Property values are converted from the Datastore value type automatically. Blob properties are returned as StringIO objects.

Examples:

Properties can be retrieved with a string name:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore
user = dataset.find "User", "[email protected]"
user["name"] #=> "Heidi Henderson"

Or with a symbol name:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore
user = dataset.find "User", "[email protected]"
user[:name] #=> "Heidi Henderson"

Getting a blob value returns a StringIO object:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore
user = dataset.find "User", "[email protected]"
user["avatar"] #=> StringIO("\x89PNG\r\n\x1A...")

Parameters:

  • prop_name (String, Symbol) —

    The name of the property.

Returns:

  • (Object, nil) —

    Returns nil if the property doesn’t exist



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# File 'lib/gcloud/datastore/entity.rb', line 80

def [] prop_name
  @properties[prop_name]
end

#[]=(prop_name, prop_value) ⇒ Object

Set a property value by name.

Property values are converted to use the proper Datastore value type automatically. Use an IO-compatible object (File, StringIO, Tempfile) to indicate the property value should be stored as a Datastore blob. IO-compatible objects are converted to StringIO objects when they are set.

Examples:

Properties can be set with a string name:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore
user = dataset.find "User", "[email protected]"
user["name"] = "Heidi H. Henderson"

Or with a symbol name:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore
user = dataset.find "User", "[email protected]"
user[:name] = "Heidi H. Henderson"

Setting a blob value using an IO:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore
user = dataset.find "User", "[email protected]"
user["avatar"] = File.open "/avatars/heidi.png"
user["avatar"] #=> StringIO("\x89PNG\r\n\x1A...")

Parameters:

  • prop_name (String, Symbol) —

    The name of the property.

  • prop_value (Object) —

    The value of the property.



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# File 'lib/gcloud/datastore/entity.rb', line 121

def []= prop_name, prop_value
  @properties[prop_name] = prop_value
end

#exclude_from_indexes!(name, flag = nil) {|value| ... } ⇒ Object

Sets whether a property should be excluded from the Datastore indexes. Setting true will exclude the property from the indexes. Setting false will include the property on any applicable indexes. The default value is false. This is another way of saying that values are indexed by default.

If the property is multi-valued, each value in the list can be managed separately for exclusion from indexing. When you call this method for a multi-valued property, you can pass either a single boolean argument to be applied to all of the values, or an array that contains the boolean argument for each corresponding value in the property. For example, if a multi-valued property contains ‘[“a”, “b”]`, and only the value `“b”` should be indexed (meaning that `“a”`’ should be excluded), you should pass the array: ‘[true, false]`.

Examples:

entity["age"] = 21
entity.exclude_from_indexes! "age", true

Multi-valued properties can be given multiple exclude flags:

entity["tags"] = ["ruby", "code"]
entity.exclude_from_indexes! "tags", [true, false]

Or, a single flag can be applied to all values in a property:

entity["tags"] = ["ruby", "code"]
entity.exclude_from_indexes! "tags", true

Flags can also be set with a block:

entity["age"] = 21
entity.exclude_from_indexes! "age" do |age|
  age > 18
end

Parameters:

  • name (String) —

    the property name

  • flag (Boolean, Array<Boolean>, nil) (defaults to: nil) —

    whether the value or values should be excluded from indexing

Yields:

  • (value) —

    a block yielding each value of the property

Yield Parameters:

  • value (Object) —

    a value of the property

Yield Returns:

  • (Boolean) —

    true if the value should be excluded from indexing

See Also:



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# File 'lib/gcloud/datastore/entity.rb', line 280

def exclude_from_indexes! name, flag = nil, &block
  name = name.to_s
  flag = block if block_given?
  if flag.nil?
    @_exclude_indexes.delete name
  else
    @_exclude_indexes[name] = flag
  end
end

#exclude_from_indexes?(name) ⇒ Boolean

Indicates if a property is flagged to be excluded from the Datastore indexes. The default value is false. This is another way of saying that values are indexed by default.

If the property is multi-valued, each value in the list can be managed separately for exclusion from indexing. Calling this method for a multi-valued property will return an array that contains the excluded boolean value for each corresponding value in the property. For example, if a multi-valued property contains ‘[“a”, “b”]`, and only the value `“b”` is indexed (meaning that `“a”`’ is excluded), the return value for this method will be ‘[true, false]`.

Examples:

Single property values will return a single flag setting:

entity["age"] = 21
entity.exclude_from_indexes? "age" #=> false

A multi-valued property will return an array of flag settings:

entity["tags"] = ["ruby", "code"]
entity.exclude_from_indexes! "tags", [true, false]

entity.exclude_from_indexes? "tags" #=> [true, false]

Returns:

  • (Boolean)

See Also:



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# File 'lib/gcloud/datastore/entity.rb', line 229

def exclude_from_indexes? name
  value = self[name]
  flag = @_exclude_indexes[name.to_s]
  map_exclude_flag_to_value flag, value
end

#persisted? ⇒ Boolean

Indicates if the record is persisted. Default is false.

Examples:

require "gcloud"

gcloud = Gcloud.new
dataset = gcloud.datastore

new_entity = Gcloud::Datastore::Entity.new
new_entity.persisted? #=> false

found_entity = dataset.find "User", "[email protected]"
found_entity.persisted? #=> true

Returns:

  • (Boolean) 


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# File 'lib/gcloud/datastore/entity.rb', line 199

def persisted?
  @key && @key.frozen?
end

#to_proto ⇒ Object 



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# File 'lib/gcloud/datastore/entity.rb', line 292

def to_proto
  entity = Proto::Entity.new.tap do |e|
    e.key = @key.to_proto
    e.property = Proto.to_proto_properties @properties.to_h
  end
  update_properties_indexed! entity
  entity
end