em-synchrony 文档链接到本文,这意味着此代码与光纤:
require 'eventmachine'
require 'fiber'
require 'em-http-request'
def http_get(url)
f = Fiber.current
http = EventMachine::HttpRequest.new(url).get
# resume fiber once http call is done
http.callback { f.resume(http) }
http.errback { f.resume(http) }
return Fiber.yield
end
EventMachine.run do
Fiber.new {
page = http_get('http://myurl')
puts "Fetched page: #{page.response}"
EventMachine.stop
}.resume
end
...等效于使用 em-synchrony 的更简单的代码:
require 'em-synchrony'
require 'em-http-request'
EventMachine.synchrony do
page = EventMachine::HttpRequest.new("http://myurl").get
p "No callbacks! Fetched page: #{page.response}"
EventMachine.stop
end
但是,运行两者会产生不同的结果。在第一个中,纤维产生直到 HTML 响应返回,而第二个似乎立即打印而不等待响应,因此打印的响应为空。我是误读还是打错了,还是文章实际上暗示了错误的事情?