出于教育目的，我最近为使用原生 Promises 的 http 和 https 模块编写了一个包装器。也就是说，我建议使用库，例如 request；这使事情变得更简单，具有单元测试覆盖率，由开源社区维护。此外，我的包装器对响应块进行了简单的字符串连接，我不相信这是构建响应主体的最高效的方式。
仅供参考：这需要 Node.js 4 或更高版本，尽管 Node 0.x.x 中的方法几乎相同。
'use strict';
const http = require('http');
const url = require('url');
module.exports = {
get(url) {
return this._makeRequest('GET', url);
},
_makeRequest(method, urlString, options) {
// create a new Promise
return new Promise((resolve, reject) => {
/* Node's URL library allows us to create a
* URL object from our request string, so we can build
* our request for http.get */
const parsedUrl = url.parse(urlString);
const requestOptions = this._createOptions(method, parsedUrl);
const request = http.get(requestOptions, res => this._onResponse(res, resolve, reject));
/* if there's an error, then reject the Promise
* (can be handled with Promise.prototype.catch) */
request.on('error', reject);
request.end();
});
},
// the options that are required by http.get
_createOptions(method, url) {
return requestOptions = {
hostname: url.hostname,
path: url.path,
port: url.port,
method
};
},
/* once http.get returns a response, build it and
* resolve or reject the Promise */
_onResponse(response, resolve, reject) {
const hasResponseFailed = response.status >= 400;
var responseBody = '';
if (hasResponseFailed) {
reject(`Request to ${response.url} failed with HTTP ${response.status}`);
}
/* the response stream's (an instance of Stream) current data. See:
* https://nodejs.org/api/stream.html#stream_event_data */
response.on('data', chunk => responseBody += chunk.toString());
// once all the data has been read, resolve the Promise
response.on('end', () => resolve(responseBody));
}
};
编辑：我才意识到你是Promises 的新手。以下是如何使用此包装器的示例：
'use strict';
const httpService = require('./httpService'); // the above wrapper
// get one URL
httpService.get('https://ron-swanson-quotes.herokuapp.com/v2/quotes').then(function gotData(data) {
console.log(data);
});
// get multiple URLs
const urls = [
'https://ron-swanson-quotes.herokuapp.com/v2/quotes',
'http://api.icndb.com/jokes/random'
];
/* map the URLs to Promises. This will actually start the
* requests, but Promise.prototype.then is always called,
* even if the operation has resolved */
const promises = urls.map(url => httpService.get(url));
Promise.all(promises).then(function gotData(responses) {
/* responses is an array containing the result of each
* Promise. This is ordered by the order of the URLs in the
* urls array */
const swansonQuote = responses[0];
const chuckNorrisQuote = responses[1];
console.log(swansonQuote);
console.log(chuckNorrisQuote);
});