IO::EAGAINWaitReadable: 资源暂时不可用 - 读取会阻塞 [英] IO::EAGAINWaitReadable: Resource temporarily unavailable - read would block

问题描述

当我尝试使用socket"库中的read_nonblock"方法时出现以下错误

I get the following error when I try to use the method "read_nonblock" from the "socket" library

IO::EAGAINWaitReadable: Resource temporarily unavailable - read would block

但是当我通过终端上的 IRB 尝试它时，它工作正常

But when I try it through the IRB on the terminal it works fine

如何让它读取缓冲区?

推荐答案

当我尝试使用方法read_nonblock"时出现以下错误；来自插座"图书馆

I get the following error when I try to use the method "read_nonblock" from the "socket" library

当缓冲区中的数据未准备好时，这是预期的行为.由于异常，IO::EAGAINWaitReadable 源自 ruby​​ 版本 2.1.0，在旧版本中，您必须使用附加的陷阱 IO::WaitReadable端口选择并重试.因此，请按照 ruby 文档 中的建议进行操作一个>:

It is expected behaviour when the data isn't ready in the buffer. Since the exception, IO::EAGAINWaitReadable is originated from ruby version 2.1.0, in older version you must trap IO::WaitReadable with additional port selection and retry. So do as it was adviced in the ruby documentation:

begin
   result = io.read_nonblock(maxlen)
rescue IO::WaitReadable
   IO.select([io])
   retry
end

对于较新版本的 os ruby​​，您也应该捕获 IO::EAGAINWaitReadable，但只是重试读取超时或无限.我还没有在文档中找到示例，但请记住它没有选择端口:

For newer version os ruby you should trap IO::EAGAINWaitReadable also, but just with retrial reading for a timeout or infinitely. I haven't found out the example in the docs, but remember that it was without port selection:

begin
   result = io.read_nonblock(maxlen)
rescue IO::EAGAINWaitReadable
   retry
end

但是我的一些调查导致最好在IO::EAGAINWaitReadable上进行端口选择，这样你就可以得到:

However some my investigations lead to that it is also better to do port selection on IO::EAGAINWaitReadable, so you'll can get:

begin
   result = io.read_nonblock(maxlen)
rescue IO::WaitReadable, IO::EAGAINWaitReadable
   IO.select([io])
   retry
end

要支持两种版本的异常代码，只需在lib/核心的if子句下声明IO::EAGAINWaitReadable的定义:

To support the code with both versions of exception, just declare the definition of IO::EAGAINWaitReadable in lib/ core under if clause:

if ! ::IO.const_defined?(:EAGAINWaitReadable)
   class ::IO::EAGAINWaitReadable; end
end

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