用nock模拟一个打开的web套接字

Question

我正在尝试使用nock对针对Oanda交易API编写的代码运行回测。为此，我需要模拟流媒体价格API(参见http://developer.oanda.com/rest-practice/streaming/上的rate streaming)。然而，nock似乎只允许您使用单个回复进行响应，即使响应是流。是否有办法发送数以千计的价格事件流作为单个请求的单独响应?

var scopeStream = nock('https://stream-fxpractice.oanda.com')
  .persist()
  .filteringPath(function(path) {
    return '/stream';
  })
  .get('/stream')
  .reply(function(uri, requestBody) {
    return [200, {"tick":{"instrument":"AUD_CAD","time":"2014-01-30T20:47:08.066398Z","bid":0.98114,"ask":0.98139}}]
  })

Answer 1

根据Nock文档，你可以在回复中返回一个ReadStream。

我使用stream-spigot npm包生成了以下示例(用于模拟马拉松赛事流):

const nock = require('nock');
const EventSource = require('eventsource');
const spigot = require('stream-spigot');
let i = 0;
nock('http://marathon.com')
      .get('/events')
      .reply(200, (uri, req) => {
          // reply with a stream
          return spigot({objectMode: true}, function() {
              const self = this;
              if (++i < 5)
                  setTimeout(() => this.push(`id: ${i}ndata: foonn`), 1000);
          })
      });
const es = new EventSource('http://marathon.com/events');
es.onmessage = m => console.log(m);
es.onerror = e => console.log(e);