class HumanQL::PostgreSQLCustomParser

Extends the generic QueryParser with additional special character and token filtering so as to avoid syntax errors with to_tsquery() (via PostgreSQLGenerator) for any known input. Note that this is still a parser for the HumanQL query language, not anything implemented in PostgreSQL.

Constants

RSQMARK: U+2019 RIGHT SINGLE QUOTATION MARK
UNDERSCORE

Public Class Methods

new(opts = {}) click to toggle source

Construct given options to set via base class or as specified below.

Options¶ ↑

:pg_version: A version string (“9.5.5”, “9.6.1”) or integer array ([9,6,1]) indicating the target PostgreSQL version. Phrase support starts in 9.6 so quoted phrases are ignored before that. Default: < 9.6

Calls superclass method

# File lib/human-ql/postgresql_custom_parser.rb, line 45
def initialize(opts = {})
  opts = opts.dup
  pg_version = opts.delete(:pg_version)
  if pg_version.is_a?(String)
    pg_version = pg_version.split('.').map(&:to_i)
  end
  pg_version ||= []

  super

  # Phrase support starts in 9.6
  if (pg_version <=> [9,6]) >= 0
    # Handle what PG-sensitive characters we can early as
    # whitespace. This can't include anything part of HumanQL,
    # e.g. ':' as used for scopes, so deal with the remainder
    # below.
    self.spaces = /[[:space:]*!<>\0\\]+/.freeze
  else
    # Disable quote tokens
    self.lquote = nil
    self.rquote = nil
    # As above but add DQUOTE as well.
    self.spaces = /[[:space:]*!<>\0\\"]+/.freeze
  end

  # Used by custom #norm_phrase_tokens as a super-set of the
  # #lparen, #rparen token patterns removed by default.  In
  # PostgreSQL, the '|' and '&' still need to be filtered. Other
  # freestanding punctuation tokens are best removed entirely.
  @phrase_token_rejects = /\A[()|&':]\z/.freeze

  # SQUOTE is a problem only when at beginning of term.
  @lead_squote = /\A'/.freeze

  # COLON is always a problem, but since its also part of Human QL
  # (scopes) it can't be included earlier in #spaces. Also per
  # scope parsing rules, its not always made a separate token.
  @term_rejects = /:/.freeze
end

Public Instance Methods

norm_phrase_tokens(tokens) click to toggle source

# File lib/human-ql/postgresql_custom_parser.rb, line 85
def norm_phrase_tokens(tokens)
  tokens.
    reject { |t| @phrase_token_rejects === t }.
    map { |t| norm_term(t) }
end

norm_term(t) click to toggle source

Replace various problem single characters with alt. characters.

# File lib/human-ql/postgresql_custom_parser.rb, line 92
def norm_term(t)
  t.sub(@lead_squote, RSQMARK).
    gsub(@term_rejects, UNDERSCORE)
end