Node.js Express中的HTTP GET请求

Question

如何从node/express中发出HTTP请求？我需要连接到另一个服务.我希望该调用是异步的,并且回调包含远程服务器响应.

Answer 1

这是我的一个样本的代码.它是异步并返回一个JSON对象.它可以做任何获取请求.请注意,有更多的最佳方式(只是一个示例) - 例如,而不是连接您放入数组并加入它的块等...希望它能让您开始朝着正确的方向前进:

const http = require('http');
const https = require('https');

/**
 * getJSON:  RESTful GET request returning JSON object(s)
 * @param options: http options object
 * @param callback: callback to pass the results JSON object(s) back
 */

module.exports.getJSON = (options, onResult) => {
  console.log('rest::getJSON');
  const port = options.port == 443 ? https : http;

  let output = '';

  const req = port.request(options, (res) => {
    console.log(`${options.host} : ${res.statusCode}`);
    res.setEncoding('utf8');

    res.on('data', (chunk) => {
      output += chunk;
    });

    res.on('end', () => {
      let obj = JSON.parse(output);

      onResult(res.statusCode, obj);
    });
  });

  req.on('error', (err) => {
    // res.send('error: ' + err.message);
  });

  req.end();
};

通过创建选项对象来调用它,例如:

const options = {
  host: 'somesite.com',
  port: 443,
  path: '/some/path',
  method: 'GET',
  headers: {
    'Content-Type': 'application/json'
  }
};

并提供回调函数.

例如,在服务中,我需要上面的其余模块,然后执行此操作.

rest.getJSON(options, (statusCode, result) => {
  // I could work with the resulting HTML/JSON here. I could also just return it
  console.log(`onResult: (${statusCode})\n\n${JSON.stringify(result)}`);

  res.statusCode = statusCode;

  res.send(result);
});

更新:

如果你正在寻找async await(线性无回调),promises,编译时支持和intellisense,我们创建一个轻量级的http和rest客户端,适合该账单:

Microsoft typed-rest-client

Answer 2

尝试使用node.js中的simple http.get(options, callback)函数:

var http = require('http');
var options = {
  host: 'www.google.com',
  path: '/index.html'
};

var req = http.get(options, function(res) {
  console.log('STATUS: ' + res.statusCode);
  console.log('HEADERS: ' + JSON.stringify(res.headers));

  // Buffer the body entirely for processing as a whole.
  var bodyChunks = [];
  res.on('data', function(chunk) {
    // You can process streamed parts here...
    bodyChunks.push(chunk);
  }).on('end', function() {
    var body = Buffer.concat(bodyChunks);
    console.log('BODY: ' + body);
    // ...and/or process the entire body here.
  })
});

req.on('error', function(e) {
  console.log('ERROR: ' + e.message);
});

还有一个通用http.request(options, callback)功能,允许您指定请求方法和其他请求详细信息.

Answer 3

Request和Superagent是非常好的库.

使用request:

var request=require('request');

request.get('https://someplace',options,function(err,res,body){
  if(err) //TODO: handle err
  if(res.statusCode !== 200 ) //etc
  //TODO Do something with response
});

Answer 4

您还可以使用Requestify,这是我为nodeJS +编写的非常酷且非常简单的HTTP客户端,它支持缓存.

只需对GET方法请求执行以下操作:

var requestify = require('requestify');

requestify.get('http://example.com/api/resource')
  .then(function(response) {
      // Get the response body (JSON parsed or jQuery object for XMLs)
      response.getBody();
  }
);

Answer 5

此版本基于最初由bryanmac函数提出,该函数使用promises,更好的错误处理,并在ES6中重写.

let http = require("http"),
    https = require("https");

/**
 * getJSON:  REST get request returning JSON object(s)
 * @param options: http options object
 */
exports.getJSON = function(options)
{
    console.log('rest::getJSON');
    let reqHandler = +options.port === 443 ? https : http;

    return new Promise((resolve, reject) => {
        let req = reqHandler.request(options, (res) =>
        {
            let output = '';
            console.log('rest::', options.host + ':' + res.statusCode);
            res.setEncoding('utf8');

            res.on('data', function (chunk) {
                output += chunk;
            });

            res.on('end', () => {
                try {
                    let obj = JSON.parse(output);
                    // console.log('rest::', obj);
                    resolve({
                        statusCode: res.statusCode,
                        data: obj
                    });
                }
                catch(err) {
                    console.error('rest::end', err);
                    reject(err);
                }
            });
        });

        req.on('error', (err) => {
            console.error('rest::request', err);
            reject(err);
        });

        req.end();
    });
};

因此,您不必传入回调函数,而是getJSON()返回一个promise.在以下示例中,该函数在ExpressJS路由处理程序中使用

router.get('/:id', (req, res, next) => {
    rest.getJSON({
        host: host,
        path: `/posts/${req.params.id}`,
        method: 'GET'
    }).then(({status, data}) => {
        res.json(data);
    }, (error) => {
        next(error);
    });
});

出错时,它将错误委托给服务器错误处理中间件.

Answer 6

Unirest是我从Node发出HTTP请求时遇到的最好的库.它的目标是成为一个多平台框架,因此,如果您需要在Ruby,PHP,Java,Python,Objective C,.Net或Windows 8上使用HTTP客户端,那么了解它如何在Node上工作将很有用.据我所知,unirest库主要由现有的HTTP客户端支持(例如,在Java,Apache HTTP客户端,在Node上,Mikeal的请求库) - Unirest只是将更好的API放在首位.

以下是Node.js的几个代码示例:

var unirest = require('unirest')

// GET a resource
unirest.get('http://httpbin.org/get')
  .query({'foo': 'bar'})
  .query({'stack': 'overflow'})
  .end(function(res) {
    if (res.error) {
      console.log('GET error', res.error)
    } else {
      console.log('GET response', res.body)
    }
  })

// POST a form with an attached file
unirest.post('http://httpbin.org/post')
  .field('foo', 'bar')
  .field('stack', 'overflow')
  .attach('myfile', 'examples.js')
  .end(function(res) {
    if (res.error) {
      console.log('POST error', res.error)
    } else {
      console.log('POST response', res.body)
    }
  })

您可以在此处直接跳转到Node文档