与Superagent保持活动连接 [英] keep-alive connection with Superagent

问题描述

我正在运行一个node.js服务器A，该服务器使用超级代理向另一个服务器B发出HTTP请求.

I'm running a node.js server A which uses superagent to issue HTTP requests to another server B.

我调查了服务器B上的请求，发现标头connection为close，而httpVersion为1.1:

I investigated the request on server B and saw the the header connection being close and the httpVersion being 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，则会得到:

However if I access the same server from a browser I get:

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

来自 http://tools.ietf.org/html/rfc2616#page-172 我了解到，除非使用Connection: close另行声明，否则keep-alive是HTTP 1.1的默认设置.

From http://tools.ietf.org/html/rfc2616#page-172 I learned that keep-alive is the default for HTTP 1.1 unless declared otherwise by using Connection: close.

所以，我的问题是:

• 为什么Superagent/Node.js明确将请求设置为不使用保持活动/持久连接?<​​/li>
• 如何强制Superagent/Node.js使用保持活动连接?
• 我如何进一步影响确切的行为(保持打开状态的连接数，超时等)?

• Why does Superagent / Node.js explicitly set the request to not use keep-alive / persistent connections?
• How can I force Superagent / Node.js to use keep-alive connections?
• How can I further influence the exact behaviour (how many connections to keep open, timeouts etc.)?

推荐答案

似乎没有记录，但是您可以使用函数agent将http代理传递给superagent. 因此，您可以使用以下模块创建一个保持活动状态的代理: https://www.npmjs.org/package/agentkeepalive 并将其传递给superagent.

It doesn't seem to be documented but you can pass an http agent to superagent with the function agent. So you could create a keep-alive agent with this module: https://www.npmjs.org/package/agentkeepalive and pass it to superagent.

类似这样的东西:

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);
  });

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