I have used filterrific gem to filter the model in rails.
Currently, I have three model, Video, Tagging, Tag
Video.rb
has_one :tagging
has_one :tag, through: :tagging
scope :by_tag, -> (tag_id) {joins(:tagging).where(taggings: {tag_id: tag_id})}
Because it's hard to use tag.name to do the filter(see StackOverflow), so I use tag_id in join table tagging to do the filter.
Tagging.rb
belongs_to :video
belongs_to :tag
Tag.rb
has_many :taggings
has_many :videos, through: :taggings
Currently, the scope is working, but I don't know how to write controller and view
In controller: How to write select_options method?
In view: How to write select method? Currently, I write like this, but not working:
f.select(:by_tag, Tag.all, { include_blank: '- Any -' }, :class=>'form-control')
Your select options that go to the select tag helper need to look like an array of pairs [ [ name, id ], [ name, id ] ... ]. Try something like this:
f.select(:by_tag, Tag.all.map {|tag| [tag.name, tag.id]}, { include_blank: '- Any -' }, :class=>'form-control')
Or to keep things even cleaner, you could use the rails collection_select helper with something like
f.collection_select(:by_tag, Tag.all, :id, :name, prompt: '- Any -', class: 'form-control')
The second one many need tweaking depending on what your controller is doing with the blank option.
There are good examples on APIDock ActionView::Helpers::FormOptionsHelper#select.