pgjwt--0.1.1--0.2.0.sql

CREATE OR REPLACE FUNCTION try_cast_double(inp text)
RETURNS double precision AS $$
  BEGIN
    BEGIN
      RETURN inp::double precision;
    EXCEPTION
      WHEN OTHERS THEN RETURN NULL;
    END;
  END;
$$ language plpgsql IMMUTABLE;


CREATE OR REPLACE FUNCTION verify(token text, secret text, algorithm text DEFAULT 'HS256')
RETURNS table(header json, payload json, valid boolean) LANGUAGE sql AS $$
  SELECT
    jwt.header AS header,
    jwt.payload AS payload,
    jwt.signature_ok AND tstzrange(
      to_timestamp(@extschema@.try_cast_double(jwt.payload->>'nbf')),
      to_timestamp(@extschema@.try_cast_double(jwt.payload->>'exp'))
    ) @> CURRENT_TIMESTAMP AS valid
  FROM (
    SELECT
      convert_from(@extschema@.url_decode(r[1]), 'utf8')::json AS header,
      convert_from(@extschema@.url_decode(r[2]), 'utf8')::json AS payload,
      r[3] = @extschema@.algorithm_sign(r[1] || '.' || r[2], secret, algorithm) AS signature_ok
    FROM regexp_split_to_array(token, '\.') r
  ) jwt
$$ IMMUTABLE;