Module: AndOne::Fingerprint

Defined in:
lib/and_one/fingerprint.rb

Overview

SQL fingerprinting without external dependencies. Normalizes queries so that the same query shape with different bind values produces the same fingerprint. Works with PostgreSQL, MySQL, and SQLite.

Class Method Summary collapse

Class Method Details

.generate(sql) ⇒ Object 



10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
 
# File 'lib/and_one/fingerprint.rb', line 10

def generate(sql)
  normalized = sql.dup

  # Remove SQL comments
  normalized.gsub!(%r{/\*[^!].*?\*/}m, "")
  normalized.gsub!(/(?:--|#)[^\r\n]*(?=[\r\n]|\z)/, "")

  # Replace double-quoted identifiers with unquoted versions (PostgreSQL/SQLite style)
  # "posts" -> posts, "posts"."id" -> posts.id
  normalized.gsub!(/"(\w+)"/, '\1')

  # Replace backtick-quoted identifiers (MySQL style)
  normalized.gsub!(/`(\w+)`/, '\1')

  # Normalize single-quoted string literals
  normalized.gsub!("\\'", "")
  normalized.gsub!(/'(?:[^'\\]|\\.)*'/m, "?")

  # Normalize numbers (standalone, not part of identifiers)
  normalized.gsub!(/\b\d+(?:\.\d+)?\b/, "?")

  # Normalize booleans and NULL
  normalized.gsub!(/\b(?:true|false)\b/i, "?")
  normalized.gsub!(/\bNULL\b/i, "?")

  # Normalize IN lists: IN (?, ?, ?) -> IN (?)
  normalized.gsub!(/\bIN\s*\(\s*\?(?:\s*,\s*\?)*\s*\)/i, "IN (?)")

  # Normalize VALUES lists
  normalized.gsub!(/\bVALUES\s*\([\s?,]*\)(?:\s*,\s*\([\s?,]*\))*/i, "VALUES (?)")

  # Normalize whitespace
  normalized.gsub!(/\s+/, " ")
  normalized.strip!
  normalized.downcase!

  # Normalize LIMIT/OFFSET
  normalized.gsub!(/\blimit \?(?:, ?\?| offset \?)?/, "limit ?")

  # Normalize $1, $2, ... placeholders (PostgreSQL)
  normalized.gsub!(/\$\d+/, "?")

  normalized
end