adapt the hackernews pages script to be also ran in async

examples/hackernews_pages.rb

@@ -1,42 +1,88 @@
 require "httpx"
 require "oga"
 
-http = HTTPX.plugin(:persistent).with(timeout: { request_timeout: 5 })
+HTTP = HTTPX.plugin(:persistent).with(timeout: { request_timeout: 5 })
 
-PAGES = (ARGV.first || 10).to_i
-pages = PAGES.times.map do |page|
-  "https://news.ycombinator.com/?p=#{page+1}"
+def get_pages(pages, mode)
+  case mode
+  when "async"
+    responses = Array.new(pages.size)
+
+    Async do
+      pages.each_with_index do |page, i|
+        Async do
+          responses[i] = HTTP.get(page)
+        end
+      end
+    end
+
+    responses
+  else
+    Array(HTTP.get(*pages))
+  end
 end
 
-links = Array.new(PAGES) { [] }
-Array(http.get(*pages)).each_with_index.map do |response, i|
-  if response.is_a?(HTTPX::ErrorResponse)
-    puts "error: #{response.error}"
-    next
-  end
-  html = Oga.parse_html(response.to_s)
-  # binding.irb
-  page_links = html.css('.athing .title a').map{|link| link.get('href') }.select { |link| URI(link).absolute? }
-  puts "page(#{i+1}): #{page_links.size}"
-  if page_links.size == 0
-    puts "error(#{response.status}) on page #{i+1}"
-    next
-  end
-  # page_links.each do |link|
-  #   puts "link: #{link}"
-  #   links[i] << http.get(link)
-  # end
-  links[i].concat(http.get(*page_links))
-end
+def fetch_pages(pages, mode)
+  links = Array.new(pages.size) { [] }
 
-links = links.each_with_index do |pages, i|
-  puts "Page: #{i+1}\t Links: #{pages.size}"
-  pages.each do |page|
-    case page
-    in status:
-      puts "URL: #{page.uri} (#{status})"
-    in error:
-      puts "URL: #{page.uri} (#{error.message})"
+  get_pages(pages, mode).each_with_index.map do |response, i|
+    if response.is_a?(HTTPX::ErrorResponse)
+      puts "error: #{response.error}"
+      next
+    end
+    html = Oga.parse_html(response.to_s)
+    # binding.irb
+    page_links = html.css('.athing .title a').map{|link| link.get('href') }.select { |link| URI(link).absolute? }
+    puts "page(#{i+1}): #{page_links.size}"
+    if page_links.size == 0
+      puts "error(#{response.status}) on page #{i+1}"
+      next
+    end
+    # page_links.each do |link|
+    #   puts "link: #{link}"
+    #   links[i] << http.get(link)
+    # end
+    links[i].concat(get_pages(page_links, mode))
+  end
+
+  links = links.each_with_index do |pages, i|
+    puts "Page: #{i+1}\t Links: #{pages.size}"
+    pages.each do |page|
+      case page
+      in status:
+        puts "URL: #{page.uri} (#{status})"
+      in error:
+        puts "URL: #{page.uri} (#{error.message})"
+      end
     end
   end
 end
+
+if __FILE__ == $0
+  pages, mode = ARGV
+
+  pages = (pages || 10).to_i
+  mode ||= "normal"
+
+  page_urls = pages.times.map do |page|
+    "https://news.ycombinator.com/?p=#{page+1}"
+  end
+
+  case mode
+  when "async"
+    require "async"
+  fetch_pages(page_urls, mode)
+  when "bench"
+    require "benchmark"
+    require "async"
+
+    Benchmark.bm do |x|
+      x.report("normal") {fetch_pages(page_urls, "normal")}
+      x.report("async"){fetch_pages(page_urls, "async")}
+    end
+  else
+
+  fetch_pages(page_urls, mode)
+  end
+
+end