Better error handling when page disconnects/unbinds.

lib/live/element.rb

@@ -7,6 +7,9 @@
 require 'securerandom'
 
 module Live
+	class PageError < RuntimeError
+	end
+
 	# Represents a single dynamic content area on the page.
 	class Element
 		def self.unique_id
@@ -66,8 +69,13 @@ def handle(event)
 		# @parameter method [Symbol] The name of the remote functio to invoke.
 		# @parameter arguments [Array]
 		def rpc(*arguments)
-			# This update might not be sent right away. Therefore, mutable arguments may be serialized to JSON at a later time (or never). This could be a race condition:
-			@page.updates.enqueue(arguments)
+			if @page
+				# This update might not be sent right away. Therefore, mutable arguments may be serialized to JSON at a later time (or never). This could be a race condition:
+				@page.updates.enqueue(arguments)
+			else
+				# This is a programming error, as it probably means the element is still part of the logic of the server side (e.g. async loop), but it is not bound to a page, so there is nothing to update/access/rpc.
+				raise PageError, "Element is not bound to a page, make sure to implement #close!"
+			end
 		end
 	end
 end

test/live/website.rb

@@ -140,4 +140,20 @@ def app
 
 		expect(session.document_title).to be == "Executed"
 	end
+
+	it "can handle disconnects" do
+		navigate_to("/index.html")
+
+		# Wait for the page to load.
+		find_element(css: "#test p")
+
+		tag = resolver.bound.values.first
+
+		# Disconnect the session:
+		navigate_to("about:blank")
+
+		expect do
+			tag.update!
+		end.to raise_exception(Live::PageError, message: be =~ /not bound/)
+	end
 end