CODEWITHSUNDEEP
rubyregexruby-on-rails-4mongoid
lucke84
lucke84

Reputation: 4636

Rails 4 and Mongoid: programmatically build query to search for different conditions on the same field

I'm building a advanced search functionality and, thanks to the help of some ruby fellows on SO, I've been already able to combine AND and OR conditions programmatically on different fields of the same class.

I ended up writing something similar to the accepted answer mentioned above, which I report here:

query = criteria.each_with_object({}) do |(field, values), query|
  field = field.in if(values.is_a?(Array))
  query[field] = values
end
MyClass.where(query)

Now, what might happen is that someone wants to search on a certain field with multiple criteria, something like: 

"all the users where names contains 'abc' but not contains 'def'"

How would you write the query above?

Please note that I already have the regexes to do what I want to (see below), my question is mainly on how to combine them together.

#contains
Regex.new('.*' + val + '.*')

#not contains
Regex.new('^((?!'+ val +').)*$')

Thanks for your time!

* UPDATE *

I was playing with the console and this is working:

MyClass.where(name: /.*abc.*/).and(name: /^((?!def).)*$/)

My question remains: how do I do that programmatically? I shouldn't end up with more than two conditions on the same field but it's something I can't be sure of.

Upvotes: 1

Views: 437

Answers (1)

mu is too short
mu is too short

Reputation: 434665

You could use an :$and operator to combine the individual queries:

MyClass.where(:$and => [
  { name: /.*abc.*/ },
  { name: /^((?!def).)*$/ }
])

That would change the overall query builder to something like this:

components = criteria.map do |field, value|
  field = field.in if(value.is_a?(Array))
  { field => value }
end
query = components.length > 1 ? { :$and => components } : components.first

You build a list of the individual components and then, at the end, either combine them with :$and or, if there aren't enough components for :$and, just unwrap the single component and call that your query.

Upvotes: 1

Related Questions