method

with_scope

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What's this?

with_scope(method_scoping = {}, action = :merge, &block) public

Scope parameters to method calls within the block. Takes a hash of method_name => parameters hash. method_name may be :find or :create. :find parameters may include the :conditions, :joins, :include, :offset, :limit, and :readonly options. :create parameters are an attributes hash.

  Article.with_scope(:find => { :conditions => "blog_id = 1" }, :create => { :blog_id => 1 }) do
    Article.find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
    a = Article.create(1)
    a.blog_id # => 1
  end

In nested scopings, all previous parameters are overwritten by inner rule except :conditions in :find, that are merged as hash.

  Article.with_scope(:find => { :conditions => "blog_id = 1", :limit => 1 }, :create => { :blog_id => 1 }) do
    Article.with_scope(:find => { :limit => 10})
      Article.find(:all) # => SELECT * from articles WHERE blog_id = 1 LIMIT 10
    end
    Article.with_scope(:find => { :conditions => "author_id = 3" })
      Article.find(:all) # => SELECT * from articles WHERE blog_id = 1 AND author_id = 3 LIMIT 1
    end
  end

You can ignore any previous scopings by using with_exclusive_scope method.

  Article.with_scope(:find => { :conditions => "blog_id = 1", :limit => 1 }) do
    Article.with_exclusive_scope(:find => { :limit => 10 })
      Article.find(:all) # => SELECT * from articles LIMIT 10
    end
  end

Show source

# File activerecord/lib/active_record/base.rb, line 901
      def with_scope(method_scoping = {}, action = :merge, &block)
        method_scoping = method_scoping.method_scoping if method_scoping.respond_to?(:method_scoping)

        # Dup first and second level of hash (method and params).
        method_scoping = method_scoping.inject({}) do |hash, (method, params)|
          hash[method] = (params == true) ? params : params.dup
          hash
        end

        method_scoping.assert_valid_keys([ :find, :create ])

        if f = method_scoping[:find]
          f.assert_valid_keys([ :conditions, :joins, :select, :include, :from, :offset, :limit, :order, :readonly, :lock ])
          f[:readonly] = true if !f[:joins].blank? && !f.has_key?(:readonly)
        end

        # Merge scopings
        if action == :merge && current_scoped_methods
          method_scoping = current_scoped_methods.inject(method_scoping) do |hash, (method, params)|
            case hash[method]
              when Hash
                if method == :find
                  (hash[method].keys + params.keys).uniq.each do |key|
                    merge = hash[method][key] && params[key] # merge if both scopes have the same key
                    if key == :conditions && merge
                      hash[method][key] = [params[key], hash[method][key]].collect{ |sql| "( %s )" % sanitize_sql(sql) }.join(" AND ")
                    elsif key == :include && merge
                      hash[method][key] = merge_includes(hash[method][key], params[key]).uniq
                    else
                      hash[method][key] = hash[method][key] || params[key]
                    end
                  end
                else
                  hash[method] = params.merge(hash[method])
                end
              else
                hash[method] = params
            end
            hash
          end
        end

        self.scoped_methods << method_scoping

        begin
          yield
        ensure
          self.scoped_methods.pop
        end
      end

January 14, 2010

0 thanks

:find takes more keys than written

The documentation says that the :find keywords “may include the :conditions, :joins, :include, :offset, :limit, and :readonly options”. Note that this does not mean that only those options are supported. :sort also works like it should, for example.

December 29, 2014 - (<= v3.0.9)

0 thanks

Rails 3.2 / 4.x with_scope replacement

If you’re looking for with_scope replacement for newer versions, see http://apidock.com/rails/ActiveRecord/Relation/scoping

with_scope

Related methods

:find takes more keys than written

Rails 3.2 / 4.x with_scope replacement