Class: Neo4j::Server::CypherNode

Inherits:
Node
  • Object
show all
Includes:
Core::ActiveEntity, Core::CypherTranslator, Resource
Defined in:
lib/neo4j-server/cypher_node.rb

Constant Summary

Constants included from Core::CypherTranslator

Core::CypherTranslator::EMPTY_PROPS, Core::CypherTranslator::SANITIZE_ESCAPED_REGEXP

Constants included from PropertyValidator

PropertyValidator::VALID_PROPERTY_VALUE_CLASSES

Instance Attribute Summary

Attributes included from Resource

#resource_data, #resource_url

Instance Method Summary collapse

Methods included from Core::ActiveEntity

#persisted?

Methods included from Core::CypherTranslator

#create_escape_value, #cypher_prop_list, #cypher_string, #escape_quotes, #escape_value, #label_string, #prop_identifier, #sanitize_escape_sequences, sanitized_column_names, translate_response

Methods included from Resource

#convert_from_json_value, #expect_response_code, #handle_response_error, #init_resource_data, #resource_headers, #resource_url_id, #response_exception, #wrap_resource

Methods inherited from Node

_load, #_rel, create, find_nodes, load

Methods included from PropertyContainer

#[], #[]=

Methods included from PropertyValidator

#valid_property?, #validate_property

Methods included from Node::Wrapper

#neo4j_obj, #wrapper

Methods included from EntityEquality

#==

Constructor Details

#initialize(session, value) ⇒ CypherNode

Returns a new instance of CypherNode.



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# File 'lib/neo4j-server/cypher_node.rb', line 7

def initialize(session, value)
  @session = session

  @id = if value.is_a?(Hash)
    hash = value['data']
    @props = Hash[hash.map{ |k, v| [k.to_sym, v] }]
    @labels = value['metadata']['labels'].map(&:to_sym) if value['metadata']
    value['id'] # value['self'].match(/\d+$/)[0].to_i
  else
    value
  end
end

Instance Method Details

#_cypher_label_list(labels) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 117

def _cypher_label_list(labels)
  ':' + labels.map{|label| "`#{label}`"}.join(':')
end

#_java_node ⇒ Object

TODO, needed by neo4j-cypher



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# File 'lib/neo4j-server/cypher_node.rb', line 29

def _java_node
  self
end

#_map_result(r) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 189

def _map_result(r)
  r.to_node_enumeration.map { |rel| rel.result }
end

#add_label(*labels) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 121

def add_label(*labels)
  @session._query_or_fail("#{match_start} SET n #{_cypher_label_list(labels)}")
end

#create_rel(type, other_node, props = nil) ⇒ Object

Creates a relationship of given type to other_node with optionally properties

Parameters:

  • type (Symbol) —

    the type of the relation between the two nodes

  • other_node (Neo4j::Node) —

    the other node

  • props (Hash<Symbol, Object>) (defaults to: nil) —

    optionally properties for the created relationship



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# File 'lib/neo4j-server/cypher_node.rb', line 34

def create_rel(type, other_node, props = nil)
  id = @session._query_or_fail(rel_string(type, other_node, props), true, cypher_prop_list(props))
  data_hash = { 'type' => type, 'data' => props, 'start' => self.neo_id.to_s, 'end' => other_node.neo_id.to_s, 'id' => id }
  CypherRelationship.new(@session, data_hash)
end

#del ⇒ Object Also known as: delete, destroy

Deletes this node from the database



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# File 'lib/neo4j-server/cypher_node.rb', line 135

def del
  @session._query_or_fail("#{match_start} MATCH n-[r]-() DELETE r")
  @session._query_or_fail("#{match_start} DELETE n")
end

#exist? ⇒ Boolean

Returns true if the node exists.

Returns:

  • (Boolean) —

    true if the node exists



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# File 'lib/neo4j-server/cypher_node.rb', line 144

def exist?
  @session._query("#{match_start} RETURN ID(n)").data.empty? ? false : true
end

#get_property(key) ⇒ Object

Directly get the property on the node (low level method, may need transaction)

Parameters:

  • key (Symbol, String)

Returns:

  • the value of the key



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# File 'lib/neo4j-server/cypher_node.rb', line 103

def get_property(key)
  if @props
    @props[key.to_sym]
  else
    @session._query_or_fail("#{match_start} RETURN n.`#{key}`", true)
  end
end

#inspect ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 24

def inspect
  "CypherNode #{neo_id} (#{object_id})"
end

#labels ⇒ Object

Returns all the Neo4j labels for this node.

Returns:

  • all the Neo4j labels for this node



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# File 'lib/neo4j-server/cypher_node.rb', line 112

def labels
  @labels ||= @session._query_or_fail("#{match_start} RETURN labels(n) as labels", true)
  @labels.map(&:to_sym)
end

#match(clazz, returns, match = {}) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 175

def match(clazz, returns, match={})
  to_dir = {outgoing: ->(rel) {"-#{rel}->"},
            incoming: ->(rel) {"<-#{rel}-"},
            both:     ->(rel) {"-#{rel}-"} }

  cypher_rel = match[:type] ? "[r:`#{match[:type]}`]" : '[r]'
  between_id = match[:between] ? "MATCH (p) WHERE ID(p) = #{match[:between].neo_id}" : ""
  dir_func = to_dir[match[:dir] || :both]
  cypher = "#{match_start} #{between_id} MATCH (n)#{dir_func.call(cypher_rel)}(p) RETURN #{returns}"
  r = @session._query(cypher)
  r.raise_error if r.error?
  _map_result(r)
end

#neo_id ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 20

def neo_id
  @id
end

#node(match = {}) ⇒ Object

Returns the only node of a given type and direction that is attached to this node, or nil. This is a convenience method that is used in the commonly occuring situation where a node has exactly zero or one relationships of a given type and direction to another node. Typically this invariant is maintained by the rest of the code: if at any time more than one such relationships exist, it is a fatal error that should generate an exception.

This method reflects that semantics and returns either:

  • nil if there are zero relationships of the given type and direction,

  • the relationship if there’s exactly one, or

  • throws an exception in all other cases.

This method should be used only in situations with an invariant as described above. In those situations, a “state-checking” method (e.g. #rel?) is not required, because this method behaves correctly “out of the box.”



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# File 'lib/neo4j-server/cypher_node.rb', line 149

def node(match={})
  ensure_single_relationship { match(CypherNode, "p as result LIMIT 2", match) }
end

#nodes(match = {}) ⇒ Enumerable<Neo4j::Node>

This method is abstract.
Note:

it’s possible that the same node is returned more than once because of several relationship reaching to the same node, see #outgoing for alternative

Works like #rels method but instead returns the nodes. It does try to load a Ruby wrapper around each node

Parameters:

  • match (Hash) (defaults to: {}) —

    the options to create a message with.

Returns:

  • (Enumerable<Neo4j::Node>) —

    an Enumeration of either Neo4j::Node objects or wrapped Neo4j::Node objects



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# File 'lib/neo4j-server/cypher_node.rb', line 165

def nodes(match={})
  match(CypherNode, "p as result", match)
end

#props ⇒ Hash<Symbol, Object>

Returns all properties of the node.

Returns:

  • (Hash<Symbol, Object>) —

    all properties of the node



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# File 'lib/neo4j-server/cypher_node.rb', line 45

def props
  if @props
    @props
  else
    hash = @session._query_entity_data("#{match_start} RETURN n")
    @props = Hash[hash['data'].map{ |k, v| [k.to_sym, v] }]
  end
end

#props=(properties) ⇒ Object

replace all properties with new properties

Parameters:

  • properties (Hash<Symbol, Object>) —

    a hash of properties the node should have



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# File 'lib/neo4j-server/cypher_node.rb', line 72

def props=(properties)
  refresh
  @session._query_or_fail("#{match_start} SET n = { props }", false, {props: properties})
  properties
end

#refresh ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 54

def refresh
  @props = nil
end

#rel(match = {}) ⇒ Object

Same as #node but returns the relationship. Notice it may raise an exception if there are more then one relationship matching.



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# File 'lib/neo4j-server/cypher_node.rb', line 154

def rel(match={})
  ensure_single_relationship { match(CypherRelationship, "r as result LIMIT 2", match) }
end

#rel?(match = {}) ⇒ Boolean

Returns true or false if there is one or more relationships

Returns:

  • (Boolean) 


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# File 'lib/neo4j-server/cypher_node.rb', line 159

def rel?(match={})
  result = match(CypherRelationship, "r as result", match)
  !!result.first
end

#rel_string(type, other_node, props) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 40

def rel_string(type, other_node, props)
  "MATCH (a), (b) WHERE ID(a) = #{neo_id} AND ID(b) = #{other_node.neo_id} CREATE (a)-[r:`#{type}` #{prop_identifier(props)}]->(b) RETURN ID(r)"
end

#rels(match = {dir: :both}) ⇒ Enumerable<Neo4j::Relationship>

Returns an enumeration of relationships. It always returns relationships of depth one.

Examples:

Return both incoming and outgoing relationships of any type

node_a.rels

All outgoing or incoming relationship of type friends

node_a.rels(type: :friends)

All outgoing relationships between me and another node of type friends

node_a.rels(type: :friends, dir: :outgoing, between: node_b)

Parameters:

  • match (Hash) (defaults to: {dir: :both}) —

    the options to create a message with.

Options Hash (match):

  • :dir (Symbol) —

    dir the direction of the relationship, allowed values: :both, :incoming, :outgoing.

  • :type (Symbol) —

    the type of relationship to navigate

  • :between (Symbol) —

    return all the relationships between this and given node

Returns:



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# File 'lib/neo4j-server/cypher_node.rb', line 170

def rels(match = {dir: :both})
  match(CypherRelationship, "r as result", match)
end

#remove_label(*labels) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 125

def remove_label(*labels)
  @session._query_or_fail("#{match_start} REMOVE n #{_cypher_label_list(labels)}")
end

#remove_properties(properties) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 78

def remove_properties(properties)
  refresh
  q = "#{match_start} REMOVE " + properties.map do |k|
    "n.`#{k}`"
  end.join(', ')
  @session._query_or_fail(q)
end

#remove_property(key) ⇒ Object

Directly remove the property on the node (low level method, may need transaction)



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# File 'lib/neo4j-server/cypher_node.rb', line 59

def remove_property(key)
  refresh
  @session._query_or_fail("#{match_start} REMOVE n.`#{key}`")
end

#set_label(*label_names) ⇒ Object 



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# File 'lib/neo4j-server/cypher_node.rb', line 129

def set_label(*label_names)
  q = "#{match_start} #{remove_labels_if_needed} #{set_labels_if_needed(label_names)}" 
  @session._query_or_fail(q)
end

#set_property(key, value) ⇒ Object

Directly set the property on the node (low level method, may need transaction)

Parameters:

  • key (Symbol, String)
  • value —

    see Neo4j::PropertyValidator::VALID_PROPERTY_VALUE_CLASSES for valid values



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# File 'lib/neo4j-server/cypher_node.rb', line 65

def set_property(key,value)
  refresh
  @session._query_or_fail("#{match_start} SET n.`#{key}` = { value }", false, value: value)
  value
end

#update_props(properties) ⇒ Object

Updates the properties, keeps old properties

Parameters:

  • properties (Hash<Symbol, Object>) —

    hash of properties that should be updated on the node



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# File 'lib/neo4j-server/cypher_node.rb', line 87

def update_props(properties)
  refresh
  return if properties.empty?

  removed_keys = properties.keys.select{|k| properties[k].nil?}
  remove_properties(removed_keys) unless removed_keys.empty?
  properties_to_set = properties.keys - removed_keys
  return if properties_to_set.empty?
  q = "#{match_start} SET " + properties_to_set.map do |k|
    "n.`#{k}`= #{escape_value(properties[k])}"
  end.join(',')
  @session._query_or_fail(q)
  properties
end