Merge pull request #326: Reuse push connections pinned to the address the guard just approved

Reviewed and merged by GPT on behalf of DHH.

config/initializers/web_push.rb

@@ -1,4 +1,5 @@
 require "web-push"
+require "web_push/connections"
 require "web_push/pool"
 require "web_push/notification"
 
@@ -17,43 +18,31 @@ end
 
 module WebPush::PersistentRequest
   def perform
-    if endpoint_ip = @options[:endpoint_ip]
-      # Pin the connection to the public IP resolved (and guarded) by
-      # Push::Subscription so delivery can't be rebound to a private address
-      # between resolution and connect. Bypasses the shared persistent pool,
-      # which would re-resolve the host itself.
-      #
-      # The explicit nil proxy address disables proxy discovery from
-      # http_proxy/https_proxy. An egress proxy would open the TCP connection
-      # itself and re-resolve the endpoint host, so http.ipaddr would no longer
-      # pin the destination and the DNS-rebinding guarantee would be lost. This
-      # path is already committed to a direct connection (it bypasses the pool);
-      # push delivery to public vendor endpoints goes direct.
-      http = Net::HTTP.new(uri.host, uri.port, nil)
-      http.ipaddr = endpoint_ip
-      http.use_ssl = true
-      http.ssl_timeout = @options[:ssl_timeout] unless @options[:ssl_timeout].nil?
-      http.open_timeout = @options[:open_timeout] unless @options[:open_timeout].nil?
-      http.read_timeout = @options[:read_timeout] unless @options[:read_timeout].nil?
-    elsif @options[:connection]
-      http = @options[:connection]
-    else
-      http = Net::HTTP.new(uri.host, uri.port, *proxy_options)
-      http.use_ssl = true
-      http.ssl_timeout = @options[:ssl_timeout] unless @options[:ssl_timeout].nil?
-      http.open_timeout = @options[:open_timeout] unless @options[:open_timeout].nil?
-      http.read_timeout = @options[:read_timeout] unless @options[:read_timeout].nil?
-    end
+    # Pin the connection to the public IP resolved (and guarded) by
+    # Push::Subscription so delivery can't be rebound to a private address
+    # between resolution and connect. There is no unpinned path: a delivery
+    # without a resolved IP is not sent.
+    endpoint_ip = @options[:endpoint_ip] or raise ArgumentError, "Push deliveries must be pinned to a resolved endpoint IP"
+
+    # The explicit nil proxy address disables proxy discovery from
+    # http_proxy/https_proxy. An egress proxy would open the TCP connection
+    # itself and re-resolve the endpoint host, so http.ipaddr would no longer
+    # pin the destination and the DNS-rebinding guarantee would be lost.
+    # Push delivery to public vendor endpoints goes direct.
+    http = Net::HTTP.new(uri.host, uri.port, nil)
+    http.ipaddr = endpoint_ip
+    http.use_ssl = true
+    http.ssl_timeout = @options[:ssl_timeout] unless @options[:ssl_timeout].nil?
+    http.open_timeout = @options[:open_timeout] unless @options[:open_timeout].nil?
+    http.read_timeout = @options[:read_timeout] unless @options[:read_timeout].nil?
 
     req = Net::HTTP::Post.new(uri.request_uri, headers)
     req.body = body
 
-    if http.is_a?(Net::HTTP::Persistent)
-      response = http.request uri, req
-    else
-      resp = http.request(req)
-      verify_response(resp)
-    end
+    # WebPush::Connections reuses an open connection only for this same host
+    # and pinned IP, so the guarantee holds for every request it sends.
+    resp = @options[:connection] ? @options[:connection].request(http, req) : http.request(req)
+    verify_response(resp)
 
     resp
   end