与Superagent保持联系

Question

我正在运行一个node.js服务器A,它使用superagent向另一台服务器B发出HTTP请求.

我调查了服务器B上的请求,看到了标题connection正在close和httpVersion 1.1:

var http = require('http');
var request = require('superagent');

http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.write('req.httpVersion seen on server:' + req.httpVersion);
  res.write('\nreq.headers.connection seen on server:' + req.headers.connection);
  res.end();
}).listen(1337, '0.0.0.0');

request
  .get('localhost:1337/helloword')
  .end(function (err, res) {
    console.log(res.text);
  });

这导致:

req.httpVersion seen on server:1.1
req.headers.connection seen on server:close

但是,如果我从浏览器访问同一台服务器,我得到:

req.httpVersion seen on server:1.1
req.headers.connection seen on server:keep-alive

从 http://tools.ietf.org/html/rfc2616#page-172我了解到这keep-alive是HTTP 1.1的默认值,除非另有声明Connection: close.

所以,我的问题是:

• 为什么Superagent/Node.js显式设置请求不使用keep-alive/persistent连接？
• 如何强制Superagent/Node.js使用保持连接？
• 如何进一步影响确切的行为(保持打开的连接数,超时数等)？

Answer 1

它似乎没有记录,但您可以通过该函数将http代理传递给superagent agent.因此,您可以使用此模块创建一个保持活动的代理:https://www.npmjs.org/package/agentkeepalive并将其传递给superagent.

像这样的东西:

util = require('util');
util.debuglog = require('debuglog');
var http = require('http');
var request = require('superagent');
var Agent = require('agentkeepalive');

var keepaliveAgent = new Agent({
  maxSockets: 100,
  maxFreeSockets: 10,
  timeout: 60000,
  keepAliveTimeout: 30000 // free socket keepalive for 30 seconds
});

http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.write('req.httpVersion seen on server:' + req.httpVersion);
  res.write('\nreq.headers.connection seen on server:' + req.headers.connection);
  res.end();
}).listen(1337, '0.0.0.0');

request
  .get('localhost:1337/helloword')
  .agent(keepaliveAgent)
  .end(function (err, res) {
    console.log(res.text);
  });