Class: SPARQL::Algebra::Operator::SHA256

Inherits:
Operator::Unary
  • Object
show all
Includes:
Evaluatable
Defined in:
lib/sparql/algebra/operator/sha256.rb

Overview

The SPARQL logical sha256 operator.

Returns the SHA256 checksum, as a hex digit string, calculated on the UTF-8 representation of the simple literal or lexical form of the xsd:string. Hex digits SHOULD be in lower case.

[121] BuiltInCall ::= ... | 'SHA256' '(' Expression ')'

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT (SHA256(?l) AS ?hash) WHERE {
 :s1 :str ?l
}

SSE

(prefix ((: <http://example.org/>))
  (project (?hash)
    (extend ((?hash (sha256 ?l)))
      (bgp (triple :s1 :str ?l)))))

See Also:

Constant Summary collapse

NAME = 
:sha256

Instance Method Summary collapse

Methods included from Evaluatable

#evaluate, #memoize, #replace_aggregate!, #replace_vars!

Instance Method Details

#apply(operand, **options) ⇒ RDF::Literal

Returns the SHA256 checksum, as a hex digit string, calculated on the UTF-8 representation of the simple literal or lexical form of the xsd:string. Hex digits should be in lower case.

Parameters:

  • operand (RDF::Literal) —

    the operand

Returns:

  • (RDF::Literal)

Raises:

  • (TypeError) —

    if the operand is not a simple literal



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# File 'lib/sparql/algebra/operator/sha256.rb', line 37

def apply(operand, **options)
  raise TypeError, "expected an RDF::Literal, but got #{operand.inspect}" unless operand.literal?
  raise TypeError, "expected simple literal or xsd:string, but got #{operand.inspect}" unless (operand.datatype || RDF::XSD.string) == RDF::XSD.string
  RDF::Literal(Digest::SHA256.new.hexdigest(operand.to_s))
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/sha256.rb', line 48

def to_sparql(**options)
  "SHA256(" + operands.to_sparql(**options) + ")"
end