Best practice for safe dynamic drops?

[kieraneglin]

Given models User and Publications where User has_many: publications, I need to iterate over a user's publications by calling {% for publication in user.publications %} and have access to methods defined in PublicationDrop.

user.publications is defined in the UserDrop class as just @user.publications.to_a.

For clarity, here is pseudocode of what I want to do:

Publications Authored by {{ user.full_name}}:

{% for publication in user.publications %}

  # These methods should come from PublicationDrop
  {{ publication.title }}

  # Displays 'No Comments' if 0, otherwise displays number of comments
  {{ publication.comment_count }}
{% endfor %}

I saw #64, and I'm sure I could adapt that to my needs. However, it is said in that thread that this method 'can have a huge security and performance impact'.

What I'm wondering is if the method described in #64 is still the best method, and if not, what is?

[pushrax]

If you define Publication#to_liquid to return a PublicationDrop then the iteration should work automatically. When you access {{ publication.title }}, you are effectively accessing publication.to_liquid.title.to_liquid.

I'm not sure if I missed something unique about this question, feel free to follow up.

Performance note: as hinted above, to_liquid is called every time a variable is accessed, so if your to_liquid is expensive to compute then it's a good idea to memoize it.