Create new DTIRequests.load_many helper, to make parallel requests

Just a wrapper for the barrier/semaphore thing we're doing constantly!

I only applied it in the importer rake tasks for now. There's other
call sites to move over to it, too!

app/services/neopets/nc_mall.rb

@@ -31,7 +31,7 @@ module Neopets::NCMall
 			]) do |response|
 				if response.status != 200
 					raise ResponseNotOK.new(response.status),
-						"expected status 200 but got #{response.status} (#{url})"
+						"expected status 200 but got #{response.status} (#{ROOT_DOCUMENT_URL})"
 				end
 
 				response.read

config/initializers/inflections.rb

@@ -16,13 +16,15 @@
 # end
 
 ActiveSupport::Inflector.inflections(:en) do |inflect|
-  # Teach Zeitwerk that `RocketAMF` is what to expect in `lib/rocketamf`.
+  # `lib/rocketamf` => `RocketAMF`
   inflect.acronym "RocketAMF"
 
-  # Teach Zeitwerk that `NeoPass` is what to expect in `neopass.rb`.
+  # `neopass.rb` => `NeoPass`
   inflect.acronym "NeoPass"
 
-  # Teach Zeitwerk that "NCMall" is what to expect in `nc_mall.rb`.
-  # (We do this by teaching it the word "NC".)
+  # `nc_mall.rb` => `NCMall`
   inflect.acronym "NC"
+
+  # `dti_requests.rb` => `DTIRequests`
+  inflect.acronym "DTI"
 end

lib/dti_requests.rb

@@ -0,0 +1,19 @@
+require "async"
+require "async/barrier"
+
+module DTIRequests
+	class << self
+		def load_many(max_at_once: 10)
+			barrier = Async::Barrier.new
+			semaphore = Async::Semaphore.new(max_at_once, parent: barrier)
+
+			Sync do
+				block_return_value = yield semaphore
+				barrier.wait # Load all the subtasks.
+				block_return_value
+			ensure
+				barrier.stop # If any subtasks failed, cancel the rest.
+			end
+		end
+	end
+end

lib/tasks/neopets/import/nc_mall.rake

@@ -85,15 +85,10 @@ def load_all_nc_mall_pages
 		links = Neopets::NCMall.load_page_links
 
 		# Next, load the linked pages, 10 at a time.
-		barrier = Async::Barrier.new
-		semaphore = Async::Semaphore.new(10, parent: barrier)
-		begin
-			linked_page_tasks = links.map do |link|
-				semaphore.async { Neopets::NCMall.load_page link[:type], link[:cat] }
+		linked_page_tasks = DTIRequests.load_many(max_at_once: 10) do |task|
+			links.map do |link|
+				task.async { Neopets::NCMall.load_page link[:type], link[:cat] }
 			end
-			barrier.wait # Load all the pages.
-		ensure
-			barrier.stop # If any pages failed, cancel the rest.
 		end
 
 		# Finally, return all the pages: the homepage, and the linked pages.

lib/tasks/neopets/import/styling_studio.rake

@@ -6,16 +6,14 @@ namespace "neopets:import" do
 		all_species = Species.order(:name).to_a
 
 		# Load 10 species pages from the NC Mall at a time.
-		barrier = Async::Barrier.new
-		semaphore = Async::Semaphore.new(10, parent: barrier)
 		styles_by_species_id = {}
-		Sync do
+		DTIRequests.load_many(max_at_once: 10) do |task|
 			num_loaded = 0
 			num_total = all_species.size
 			print "0/#{num_total} species loaded"
 
 			all_species.each do |species|
-				semaphore.async {
+				task.async {
 					begin
 						styles_by_species_id[species.id] = Neopets::NCMall.load_styles(
 							species_id: species.id,
@@ -28,11 +26,6 @@ namespace "neopets:import" do
 					print "\r#{num_loaded}/#{num_total} species loaded"
 				}
 			end
-
-			# Wait until all tasks are done.
-			barrier.wait
-		ensure
-			barrier.stop # If something goes wrong, clean up all tasks.
 		end
 		print "\n"