ruby-on-rails - Rails 使用逻辑运算符搜索 ActiveRecord

Question

我想知道在 Rails 中解析文本查询的最佳方法是什么，以允许用户包含逻辑运算符？

我希望用户能够输入其中任何一个，或一些等效的:

# searching partial text in emails, just for example
# query A
"jon AND gmail" #=> ["jonsmith@gmail.com"]

# query B
"jon OR gmail" #=> ["jonsmith@gmail.com", "sarahcalaway@gmail.com"]

# query C
"jon AND gmail AND smith" #=> ["jonsmith@gmail.com"]

理想情况下，我们可以使用括号来指示操作顺序，从而变得更加复杂，但这不是必需的。

是否有支持此操作的 gem 或模式？

Answer 1

这是一种可行但效率低下的方法:

user_input = "jon myers AND gmail AND smith OR goldberg OR MOORE"
terms = user_input.split(/(.+?)((?: and | or ))/i).reject(&:empty?)
# => ["jon myers", " AND ", "gmail", " AND ", "smith", " OR ", "goldberg", " OR ", "MOORE"]

pairs = terms.each_slice(2).map { |text, op| ["column LIKE ? #{op} ", "%#{text}%"] }
# => [["column LIKE ?  AND  ", "%jon myers%"], ["column LIKE ?  AND  ", "%gmail%"], ["column LIKE ?  OR  ", "%smith%"], ["column LIKE ?  OR  ", "%goldberg%"], ["column LIKE ?  ", "%MOORE%"]]

query = pairs.reduce([""]) { |acc, terms| acc[0] += terms[0]; acc << terms[1] }
# => ["column LIKE ?  AND  column LIKE ?  AND  column LIKE ?  OR column LIKE ?  OR  column LIKE ?  ", "%jon myers%", "%gmail%", "%smith%", "%goldberg%", "%MOORE%"]

Model.where(query[0], *query[1..-1]).to_sql
# => SELECT "courses".* FROM "courses"  WHERE (column LIKE '%jon myers%'  AND  column LIKE '%gmail%'  AND  column LIKE '%smith%'  OR  column LIKE '%goldberg%'  OR  column LIKE '%MOORE%'  )

但是，正如我所说，像这样的搜索效率极低。我建议您使用全文搜索引擎，例如 Elasticsearch .