Add support to custom mappers

[wagner]

I've hacked some code (https://github.com/wagner/search_cop/commit/e66ec0156fee0e0782f39eea1b2b94a0c2fe5b95) to allow a custom mapper for a brainspec/enumerize attribute:

class Comment < ActiveRecord::Base
  include SearchCop
  extend Enumerize

  belongs_to :user

  enumerize :state, in: {:new => 1, :approved => 2, :rejected => 3}, default: :new

  search_scope :search do
    ...
    options :state, :enumerator => Comment.state
  end
end

Comment.search("state: rejected")

But after I realized a custom mapper option could be more useful to everyone with similar needs. Something like this:

  search_scope :search do
    ...
    options :state, :mapper => lambda { |value| Comment.state.find_value(value).value }
  end

What do you think?

[mrkamel]

I think this would be a nice feature. I'm not sure whether or not the naming :mapper => ... is fully self explanatory, but we'll find a proper solution.

The actual mapping should probably happen in https://github.com/mrkamel/search_cop/blob/master/lib/search_cop_grammar/attributes.rb

Wanna create a PR?

[wagner]

Sure! Are you ok with the Proc within the options hash?

[mrkamel]

Sure, i'm fine with it

[westonganger]

+1

[westonganger]

This feature was added as part of #35

Example usage:

class Book
  include SearchCop

  enum types: {
    foo: 0,
    bar: 1,
  }
  
  search_scope :search do
    attributes :number, :my_enum
  
    generator :like_string do |column_name, raw_value|
      pattern = quote("%#{raw_value}%")
      "#{column_name} LIKE #{pattern}"
    end
  
    generator :match_type_enum do |column_name, raw_value|
      type_int = types[raw_value]
      "#{column_name} = #{type_int}"
    end
  end

end

Book.search(number: {like_string: "123"}, my_enum: {match_type_enum: "foo"})

[kylewelsby]

Here is another workaround for the enum issue.

class Book
  include SearchCop
  enum status: {draft: 0, published: 1, archived: 2}

  search_scope :search do |query|
    attributes :status
  end

  def self.search_with_enum(query)
    query = preprocess_query(query)
    search(query)
  end

  def self.preprocess_query(query)
    # Regular expression to match status queries with comparison operators
    query.gsub!(/status\s*(:|=|!=|>=|>|<=|<)\s*(\w+)/) do |match|
      operator = $1
      status_key = $2
      status_value = statuses[status_key]
      if status_value
        "status #{operator} #{status_value}"
      else
        match
      end
    end
    query
  end
end

Book.search_with_enum("status:published").to_sql
# => `SELECT "books".* FROM "books" WHERE ("books"."status" = 1)`