Fragment caching in Rails

[HellRok]

I'm wondering if there's any way to use Rails fragment caching with Phlex?

I've got this basic view which tries to write to the cache but since the rendering happens later instead of being returned, it's caching nil

class Home::IndexView < ApplicationView
  def initialize(posts:)
    @posts = posts
  end

  def view_template
    # Breadcrumbs
    content_for(:breadcrumbs) {
      plain "Home"
    }

    @posts.each do |post|
      helpers.cache post do
        render Posts::SummaryComponent.new(
          post: post
        )
      end
    end
  end
end

I had a brief look at the code for Phlex and didn't see anything obvious that matches what I'm trying to do. Have I missed something? Is there a different way to do fragment caching I'm not aware of?

[ccrisc]

In Rails to use fragment caching effectively with Phlex you should return the content as a string. So you need to capture the output of the Phlex component rendering and then cache it. You can try to use a buffer:

@posts.each do |post|
  cached_post = helpers.cache(post) do
    capture do
      render Posts::SummaryComponent.new(post: post)
    end
  end

  text cached_post
end

[HellRok]

Interestingly this isn't working for me. I'm trying with this code and just getting blank results:

@posts.each do |post|
  cached_post = helpers.cache(post) do
    capture do
      render Posts::SummaryComponent.new(post: post)
    end
  end

  plain cached_post
end

The interesting part is that this does work (obviously without caching):

@posts.each do |post|
  cached_post = capture do
    render Posts::SummaryComponent.new(post: post)
  end

  plain cached_post
end

[joeldrapper]

It’s not possible to use fragment caching with Phlex, because you would need to track all the dependencies. Even ActionView doesn’t do this very well. However, Phlex is so fast, it’s not necessary to use fragment caching. You can use caching to speed up database queries or API requests, while continuing to render views on the fly. The views won't be the bottleneck.