显式绑定

🌐 Explicit binding

有时，正在使用的域并不是某个特定事件触发器应该使用的域。或者，事件触发器可能是在一个域的上下文中创建的，但本应绑定到另一个域。

🌐 Sometimes, the domain in use is not the one that ought to be used for a specific event emitter. Or, the event emitter could have been created in the context of one domain, but ought to instead be bound to some other domain.

例如，可能有一个域名用于 HTTP 服务器，但我们可能希望为每个请求使用一个单独的域名。

🌐 For example, there could be one domain in use for an HTTP server, but perhaps we would like to have a separate domain to use for each request.

这可以通过显式绑定来实现。

🌐 That is possible via explicit binding.

// Create a top-level domain for the server
const domain = require('node:domain');
const http = require('node:http');
const serverDomain = domain.create();

serverDomain.run(() => {
  // Server is created in the scope of serverDomain
  http.createServer((req, res) => {
    // Req and res are also created in the scope of serverDomain
    // however, we'd prefer to have a separate domain for each request.
    // create it first thing, and add req and res to it.
    const reqd = domain.create();
    reqd.add(req);
    reqd.add(res);
    reqd.on('error', (er) => {
      console.error('Error', er, req.url);
      try {
        res.writeHead(500);
        res.end('Error occurred, sorry.');
      } catch (er2) {
        console.error('Error sending 500', er2, req.url);
      }
    });
  }).listen(1337);
}); 拷贝