Inertia SSR (#74)

* wip

* bugfix and better naming

* Add test

Co-authored-by: Brandon Shar <[email protected]>

Author: BrandonShar

lib/inertia_rails/controller.rb

@@ -1,4 +1,5 @@
 require_relative "inertia_rails"
+require_relative "helper"
 
 module InertiaRails
   module Controller
@@ -9,6 +10,7 @@ module Controller
         # :inertia_errors are deleted from the session by the middleware
         InertiaRails.share(errors: session[:inertia_errors]) if session[:inertia_errors].present?
       end
+      helper ::InertiaRails::Helper
     end
 
     module ClassMethods

lib/inertia_rails/helper.rb

@@ -0,0 +1,7 @@
+require_relative 'inertia_rails'
+
+module InertiaRails::Helper
+  def inertia_headers
+    ::InertiaRails.html_headers.join.html_safe
+  end
+end

lib/inertia_rails/inertia_rails.rb

@@ -5,6 +5,7 @@
 module InertiaRails
   thread_mattr_accessor :threadsafe_shared_plain_data
   thread_mattr_accessor :threadsafe_shared_blocks
+  thread_mattr_accessor :threadsafe_html_headers
 
   def self.configure
     yield(Configuration)
@@ -23,6 +24,18 @@ def self.layout
     Configuration.layout
   end
 
+  def self.ssr_enabled?
+    Configuration.ssr_enabled
+  end
+
+  def self.ssr_url
+    Configuration.ssr_url
+  end
+
+  def self.html_headers
+    self.threadsafe_html_headers || []
+  end
+
   # "Setters"
   def self.share(**args)
     self.shared_plain_data = self.shared_plain_data.merge(args)
@@ -32,9 +45,14 @@ def self.share_block(block)
     self.shared_blocks = self.shared_blocks + [block]
   end
 
+  def self.html_headers=(headers)
+    self.threadsafe_html_headers = headers
+  end
+
   def self.reset!
     self.shared_plain_data = {}
     self.shared_blocks = []
+    self.html_headers = []
   end
 
   def self.lazy(value = nil, &block)
@@ -46,6 +64,8 @@ def self.lazy(value = nil, &block)
   module Configuration
     mattr_accessor(:layout) { 'application' }
     mattr_accessor(:version) { nil }
+    mattr_accessor(:ssr_enabled) { false }
+    mattr_accessor(:ssr_url) { 'http://localhost:13714' }
 
     def self.evaluated_version
       self.version.respond_to?(:call) ? self.version.call : self.version

lib/inertia_rails/renderer.rb

@@ -1,3 +1,5 @@
+require 'net/http'
+require 'json'
 require_relative "inertia_rails"
 
 module InertiaRails
@@ -15,6 +17,8 @@ def initialize(component, controller, request, response, render_method, props:,
     end
 
     def render
+      return render_ssr if ::InertiaRails.ssr_enabled?
+
       if @request.headers['X-Inertia']
         @response.set_header('Vary', 'Accept')
         @response.set_header('X-Inertia', 'true')
@@ -26,6 +30,14 @@ def render
 
     private
 
+    def render_ssr
+      uri = URI("#{::InertiaRails.ssr_url}/render")
+      res = JSON.parse(Net::HTTP.post(uri, page.to_json, 'Content-Type' => 'application/json').body)
+      
+      ::InertiaRails.html_headers = res['head']
+      @render_method.call html: res['body'].html_safe, layout: ::InertiaRails.layout, locals: (view_data).merge({page: page})
+    end
+
     def props
       _props = ::InertiaRails.shared_data(@controller).merge(@props).select do |key, prop|
         if rendering_partial_component?

spec/dummy/app/views/layouts/application.html.erb

@@ -1,2 +1,3 @@
+<%= inertia_headers %>
 <%= yield %>
 <%= local_assigns.except(:page).to_json.html_safe %>

spec/inertia/ssr_spec.rb

@@ -0,0 +1,39 @@
+RSpec.describe 'inertia ssr', type: :request do
+  context 'ssr is enabled' do
+    before do
+      InertiaRails.reset!
+      InertiaRails.configure do |config|
+        config.ssr_enabled = true
+        config.ssr_url = 'ssr-url'
+        config.version = '1.0'
+      end
+    end
+
+    it 'returns the result of the ssr call' do
+      allow(Net::HTTP).to receive(:post)
+        .with(
+          URI('ssr-url/render'),
+          {
+            component: 'TestComponent',
+            props: {name: 'Brandon', sport: 'hockey'},
+            url: props_path,
+            version: '1.0',
+          }.to_json,
+          'Content-Type' => 'application/json'
+        )
+        .and_return(OpenStruct.new(
+          body: {
+            body: '<div>Test works</div>',
+            head: ['<title>Title works</title>'],
+          }.to_json
+        ))
+
+
+      get props_path
+
+
+      expect(response.body).to include('<title>Title works</title>')
+      expect(response.body).to include('<div>Test works</div>')
+    end
+  end
+end