class BSON::Document
This module provides behaviour for serializing and deserializing entire BSON
documents, according to the BSON
specification.
@note The specification is: document ::= int32 e_list “x00”
@see bsonspec.org/#/specification
@since 2.0.0
Public Class Methods
Instantiate a new Document
. Valid parameters for instantiation is a hash only or nothing.
@example Create the new Document
.
BSON::Document.new(name: "Joe", age: 33)
@param [ Hash
] elements The elements of the document.
@since 3.0.0
# File lib/bson/document.rb, line 212 def initialize(elements = nil) super() (elements || {}).each_pair{ |key, value| self[key] = value } end
Public Instance Methods
Get a value from the document for the provided key. Can use string or symbol access, with string access being the faster of the two.
@example Get an element for the key.
document["field"]
@example Get an element for the key by symbol.
document[:field]
@param [ String
, Symbol
] key The key to look up.
@return [ Object
] The found value, or nil if none found.
@since 2.0.0
# File lib/bson/document.rb, line 88 def [](key) super(convert_key(key)) end
Stores a key-value pair in the current document.
Since BSON
documents provide deep indifferent access (both strings and symbols are accepted as keys, recursively), the value may be converted to facilitate indifferent access. This conversion is performed for built-in Array
and Hash
classes, and other classes can override to_bson_normalized_value
method to provide custom conversion logic. For example:
doc = BSON::Document.new doc[:a] = {b: {c: 'd'}} doc['a']['b']['c'] # => "d"
Note that due to this conversion, the object that is stored in the receiver Document
may be different from the object supplied as the right hand side of the assignment. In Ruby, the result of assignment is the right hand side, not the return value of []= method. Because of this, modifying the result of assignment generally does not work as intended:
doc = BSON::Document.new foo = (doc[:a] = {b: {c: 'd'}}) # foo is original Hash with symbol keys foo['test'] = 'test' # doc is not modified doc # => {"a"=>{"b"=>{"c"=>"d"}}}
This behavior can be encountered when defaulting document contents with []= in a method, such as:
def foo # @doc is a BSON::Document @doc[:foo] ||= calculation end
The above method should be written as follows to allow chaining:
def foo # @doc is a BSON::Document @doc[:foo] ||= calculation and @doc[:foo] end
@example Set a value on the document.
document[:test] = "value"
@param [ String
, Symbol
] key The key to update. @param [ Object
] value The value to update.
@return [ Object
] The updated value.
@since 3.0.0
# File lib/bson/document.rb, line 145 def []=(key, value) super(convert_key(key), convert_value(value)) end
Deletes the key-value pair and returns the value from the document whose key is equal to key. If the key is not found, returns the default value. If the optional code block is given and the key is not found, pass in the key and return the result of block.
@example Delete a key-value pair
document.delete(:test)
@param [ Object
] key The key of the key-value pair to delete.
@return [ Object
]
@since 4.0.0
# File lib/bson/document.rb, line 199 def delete(key, &block) super(convert_key(key), &block) end
Retrieves the value object corresponding to the each key objects repeatedly. Will normalize symbol keys into strings.
@example Get value from nested sub-documents, handling missing levels.
document # => { :key1 => { "key2" => "value"}} document.dig(:key1, :key2) # => "value" document.dig("key1", "key2") # => "value" document.dig("foo", "key2") # => nil
@param [ Array
<String, Symbol> ] *keys Keys, which constitute a “path” to the nested value.
@return [ Object
, NilClass
] The requested value or nil.
@since 3.0.0
# File lib/bson/document.rb, line 268 def dig(*keys) super(*keys.map{|key| convert_key(key)}) end
Returns a new document consisting of the current document minus the specified keys.
The keys to be removed can be specified as either strings or symbols.
@example Get a document/hash with only the ‘name` and `age` fields removed
document # => { _id: <ObjectId>, :name => 'John', :age => 30, :location => 'Earth' } document.except(:name, 'age') # => { _id: <ObjectId>, location: 'Earth' }
@param [ Array
<String, Symbol> ] *keys Keys, that will be removed in the resulting document
@return [ BSON::Document
] The document with the specified keys removed.
@note This method is always defined, even if Hash
already contains a
definition of #except, because ActiveSupport unconditionally defines its version of #except which doesn't work for BSON::Document which causes problems if ActiveSupport is loaded after bson-ruby is.
# File lib/bson/document.rb, line 313 def except(*keys) copy = dup keys.each {|key| copy.delete(key)} copy end
Get a value from the document for the provided key. Can use string or symbol access, with string access being the faster of the two.
@overload fetch(key)
Returns a value from the hash for the given key. If the key does not exist, raises KeyError exception.
@overload fetch(key, default)
Returns a value from the hash for the given key. If the key does not exist, returns *default*.
@overload fetch(key, &block)
Returns a value from the hash for the given key. If the key does not exist, returns the value of the block called with the key.
@example Get an element for the key.
document.fetch("field")
@example Get an element for the key by symbol with a default.
document.fetch(:field, 'foo')
@example Get an element for the key by symbol with a block default.
document.fetch(:field) { |key| key.upcase }
@param [ String
, Symbol
] key The key to look up. @param [ Object
] default Returned value if key does not exist. @yield [key] Block returning default value for the given key.
@return [ Object
] The found value. Raises KeyError if none found.
@since 4.4.0
# File lib/bson/document.rb, line 69 def fetch(key, *args, &block) key = convert_key(key) super(key, *args, &block) end
Returns true if the given key is present in the document. Will normalize symbol keys into strings.
@example Test if a key exists using a symbol
document.has_key?(:test)
@param [ Object
] key The key to check for.
@return [ true, false]
@since 4.0.0
# File lib/bson/document.rb, line 160 def has_key?(key) super(convert_key(key)) end
Returns true if the given value is present in the document. Will normalize symbols into strings.
@example Test if a key exists using a symbol
document.has_value?(:test)
@param [ Object
] value THe value to check for.
@return [ true, false]
@since 4.0.0
# File lib/bson/document.rb, line 179 def has_value?(value) super(convert_value(value)) end
Merge this document with another document, returning a new document in the process.
@example Merge with another document.
document.merge(name: "Bob")
@param [ BSON::Document
, Hash
] other The document/hash to merge with.
@return [ BSON::Document
] The result of the merge.
@since 3.0.0
# File lib/bson/document.rb, line 228 def merge(other, &block) dup.merge!(other, &block) end
Merge this document with another document, returning the same document in the process.
@example Merge with another document.
document.merge(name: "Bob")
@param [ BSON::Document
, Hash
] other The document/hash to merge with.
@return [ BSON::Document
] The result of the merge.
@since 3.0.0
# File lib/bson/document.rb, line 243 def merge!(other) other.each_pair do |key, value| value = yield(convert_key(key), self[key], convert_value(value)) if block_given? && self[key] self[key] = value end self end
Slices a document to include only the given keys. Will normalize symbol keys into strings. (this method is backported from ActiveSupport::Hash)
@example Get a document/hash with only the ‘name` and `age` fields present
document # => { _id: <ObjectId>, :name => "John", :age => 30, :location => "Earth" } document.slice(:name, 'age') # => { "name": "John", "age" => 30 } document.slice('name') # => { "name" => "John" } document.slice(:foo) # => {}
@param [ Array
<String, Symbol> ] *keys Keys, that will be kept in the resulting document
@return [ BSON::Document
] The document with only the selected keys
@since 4.3.1
# File lib/bson/document.rb, line 288 def slice(*keys) keys.each_with_object(self.class.new) do |key, hash| if key?(key) hash[key] = self[key] end end end
# File lib/bson/document.rb, line 319 def symbolize_keys! raise ArgumentError, 'symbolize_keys! is not supported on BSON::Document instances. Please convert the document to hash first (using #to_h), then call #symbolize_keys! on the Hash instance' end
Override the Hash
implementation of to_bson_normalized_value.
BSON::Document
is already of the correct type and already provides indifferent access to keys, hence no further conversions are necessary.
Attempting to perform Hash’s conversion on Document
instances converts DBRefs to Documents which is wrong.
@return [ BSON::Document
] The normalized hash.
# File lib/bson/document.rb, line 332 def to_bson_normalized_value self end
Private Instance Methods
# File lib/bson/document.rb, line 338 def convert_key(key) key.to_bson_normalized_key end
# File lib/bson/document.rb, line 342 def convert_value(value) value.to_bson_normalized_value end