Multi-format Response

In Ruby on Rails, respond_to is a method that allows you to define how your controller should respond to different types of requests.

class PostsController < ApplicationController
  def create
    @post = Post.new(post_params)

    respond_to do |format|
      if @post.save
        format.html { redirect_to @post, notice: 'Post was successfully created.' }
        format.json { render json: @post, status: :created }
        format.turbo_stream { render turbo_stream: turbo_stream.append(@post) }
      else
        format.html { render :new }
        format.json { render json: @post.errors, status: :unprocessable_entity }
        format.turbo_stream { render turbo_stream: turbo_stream.replace('new_post', partial: 'posts/form', locals: { post: @post }) }
      end
    end
  end
end

In the above code, developer can return different response format based on request Accept header.

We can do similar approach with turbo_helper

from turbo_helper import (
  TurboStreamResponse,
  respond_to,
)

class TaskCreateView(LoginRequiredMixin, CreateView):
    def form_valid(self, form):
        response = super().form_valid(form)
        request = self.request
        messages.success(request, "Created successfully")

        with respond_to(request) as resp_format:
          if resp_format.turbo_stream:
            return TurboStreamResponse(
              render_to_string(
                "task_create_success.turbo_stream.html",
                context={
                  "form": TaskForm(),
                },
                request=self.request,
              ),
            )
          if resp_format.html:
            return response

Notes:

1. If the browser accepts turbo stream (Accept header should explicitly contain text/vnd.turbo-stream.html), we return turbo stream response.

2. If the browser accepts HTML (*/* in Accept also work), we return HTML response.

3. This is useful when we want to migrate our Django app from normal web page to turbo stream gradually.

Note

Please put the non html response before html response, and use html response as the fallback response.