require("http").request(options, cb)的一些研究

由于决定用couthDB做我的默认数据库，于是用到http.request，但请求死活发不出去

定位到1144行

// require("http").request(options, cb)
 function ClientRequest(options, cb) {
  var self = this;
  OutgoingMessage.call(self);

  self.agent = options.agent === undefined ? globalAgent : options.agent;//是否使用代理

  var defaultPort = options.defaultPort || 80;

  var port = options.port || defaultPort;
  var host = options.hostname || options.host || 'localhost';

  if (options.setHost === undefined) {
    var setHost = true;
  }

  self.socketPath = options.socketPath;

  var method = self.method = (options.method || 'GET').toUpperCase();
  self.path = options.path || '/';
  if (cb) {
    self.once('response', cb);
  }

  if (!Array.isArray(options.headers)) {
    if (options.headers) {
      var keys = Object.keys(options.headers);
      for (var i = 0, l = keys.length; i < l; i++) {
        var key = keys[i];
        self.setHeader(key, options.headers[key]);
      }
    }
    if (host && !this.getHeader('host') && setHost) {
      var hostHeader = host;
      if (port && +port !== defaultPort) {
        hostHeader += ':' + port;
      }
      this.setHeader('Host', hostHeader);
    }
  }

  if (options.auth && !this.getHeader('Authorization')) {
    //basic auth
    this.setHeader('Authorization', 'Basic ' +
                   new Buffer(options.auth).toString('base64'));
  }

  if (method === 'GET' || method === 'HEAD' || method === 'CONNECT') {
    self.useChunkedEncodingByDefault = false;
  } else {
    self.useChunkedEncodingByDefault = true;
  }

  if (Array.isArray(options.headers)) {
    self._storeHeader(self.method + ' ' + self.path + ' HTTP/1.1\r\n',
                      options.headers);
  } else if (self.getHeader('expect')) {
    self._storeHeader(self.method + ' ' + self.path + ' HTTP/1.1\r\n',
                      self._renderHeaders());
  }
  if (self.socketPath) {
    self._last = true;
    self.shouldKeepAlive = false;
    if (options.createConnection) {
      self.onSocket(options.createConnection(self.socketPath));
    } else {
      self.onSocket(net.createConnection(self.socketPath));
    }
  } else if (self.agent) {
    // If there is an agent we should default to Connection:keep-alive.
    self._last = false;
    self.shouldKeepAlive = true;
    self.agent.addRequest(self, host, port, options.localAddress);
  } else {
    // No agent, default to Connection:close.
    self._last = true;
    self.shouldKeepAlive = false;
    if (options.createConnection) {
      options.port = port;
      options.host = host;
      var conn = options.createConnection(options);
    } else {
      var conn = net.createConnection({
        port: port,
        host: host,
        localAddress: options.localAddress
      });
    }
    self.onSocket(conn);
  }

  self._deferToConnect(null, null, function() {
    self._flush();
    self = null;
  });

}
util.inherits(ClientRequest, OutgoingMessage);

exports.ClientRequest = ClientRequest;

没有结果，这只是一个类，继续

exports.request = function(options, cb) {
  if (typeof options === 'string') {
    options = url.parse(options);
  }

  if (options.protocol && options.protocol !== 'http:') {
    throw new Error('Protocol:' + options.protocol + ' not supported.');
  }

  return new ClientRequest(options, cb);
};

exports.get = function(options, cb) {
  var req = exports.request(options, cb);
  req.end();
  return req;
};

发现http.get比http.request唯一要多做的是加了个req.end()，崩溃！

另，此回调果真只有一个参数，即http.createServer(function(req, res) {})的第二个参数一样！

我们只要加个end就可以让程序运行了！（要先安装与启到couthDB）

var http = require('http');

var options = {
    port: 5984,
    method: 'GET'
};
//这个回调果真只有一个参数，即http.createServer(function(req, res) {})
var req = http.request(options, function(res) {
    console.log('STATUS: ' + res.statusCode);
    console.log('HEADERS: ' + JSON.stringify(res.headers));
    res.setEncoding('utf8');
    var body = ""
    res.on('data', function (chunk) {
        body += chunk
    });
    res.once("end", function(){
        var json = JSON.parse(body);
        console.log(json)
    })
});
req.end()
req.on('error', function(e) {
  console.log('problem with request: ' + e.message);
});