如何从Node.js或Express.js中发出HTTP请求?我需要连接到另一个服务。我希望调用是异步的,并且回调包含远程服务器的响应。


当前回答

## you can use request module and promise in express to make any request ##
const promise                       = require('promise');
const requestModule                 = require('request');

const curlRequest =(requestOption) =>{
    return new Promise((resolve, reject)=> {
        requestModule(requestOption, (error, response, body) => {
            try {
                if (error) {
                    throw error;
                }
                if (body) {

                    try {
                        body = (body) ? JSON.parse(body) : body;
                        resolve(body);
                    }catch(error){
                        resolve(body);
                    }

                } else {

                    throw new Error('something wrong');
                }
            } catch (error) {

                reject(error);
            }
        })
    })
};

const option = {
    url : uri,
    method : "GET",
    headers : {

    }
};


curlRequest(option).then((data)=>{
}).catch((err)=>{
})

其他回答

这个版本是基于bryanmac函数最初提出的,它使用承诺,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()返回一个承诺。在下面的例子中,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(({ statusCode, data }) => {
        res.json(data);
    }, (error) => {
        next(error);
    });
});

当出现错误时,它将错误委托给服务器错误处理中间件。

使用reqclient:不是为脚本目的设计的 像request或者其他库。Reqclient允许在构造函数中使用 在需要重用时指定许多有用的配置 配置一次又一次:基本URL,头,认证选项, 日志记录选项,缓存等。也有有用的功能,如 查询和URL解析,自动查询编码和JSON解析等。

使用库的最佳方法是创建一个模块来导出对象 指向API和需要连接的必要配置:

模块client.js:

let RequestClient = require("reqclient").RequestClient

let client = new RequestClient({
  baseUrl: "https://myapp.com/api/v1",
  cache: true,
  auth: {user: "admin", pass: "secret"}
})

module.exports = client

在你需要使用API的控制器中,像这样使用:

let client = require('client')
//let router = ...

router.get('/dashboard', (req, res) => {
  // Simple GET with Promise handling to https://myapp.com/api/v1/reports/clients
  client.get("reports/clients")
    .then(response => {
       console.log("Report for client", response.userId)  // REST responses are parsed as JSON objects
       res.render('clients/dashboard', {title: 'Customer Report', report: response})
    })
    .catch(err => {
      console.error("Ups!", err)
      res.status(400).render('error', {error: err})
    })
})

router.get('/orders', (req, res, next) => {
  // GET with query (https://myapp.com/api/v1/orders?state=open&limit=10)
  client.get({"uri": "orders", "query": {"state": "open", "limit": 10}})
    .then(orders => {
      res.render('clients/orders', {title: 'Customer Orders', orders: orders})
    })
    .catch(err => someErrorHandler(req, res, next))
})

router.delete('/orders', (req, res, next) => {
  // DELETE with params (https://myapp.com/api/v1/orders/1234/A987)
  client.delete({
    "uri": "orders/{client}/{id}",
    "params": {"client": "A987", "id": 1234}
  })
  .then(resp => res.status(204))
  .catch(err => someErrorHandler(req, res, next))
})

Reqclient支持许多特性,但是它有一些其他特性不支持的特性 库:OAuth2集成和记录器集成 使用cURL语法,并且总是返回本机Promise对象。

如果你只需要简单的get请求,不需要支持任何其他HTTP方法,看看:

var get = require('simple-get');

get('http://example.com', function (err, res) {
  if (err) throw err;
  console.log(res.statusCode); // 200
  res.pipe(process.stdout); // `res` is a stream
});

如果你需要向一个IP和一个域发送GET请求(其他答案没有提到你可以指定一个端口变量),你可以使用这个函数:

function getCode(host, port, path, queryString) {
    console.log("(" + host + ":" + port + path + ")" + "Running httpHelper.getCode()")

    // Construct url and query string
    const requestUrl = url.parse(url.format({
        protocol: 'http',
        hostname: host,
        pathname: path,
        port: port,
        query: queryString
    }));

    console.log("(" + host + path + ")" + "Sending GET request")
    // Send request
    console.log(url.format(requestUrl))
    http.get(url.format(requestUrl), (resp) => {
        let data = '';

        // A chunk of data has been received.
        resp.on('data', (chunk) => {
            console.log("GET chunk: " + chunk);
            data += chunk;
        });

        // The whole response has been received. Print out the result.
        resp.on('end', () => {
            console.log("GET end of response: " + data);
        });

    }).on("error", (err) => {
        console.log("GET Error: " + err);
    });
}

不要错过文件顶部的require模块:

http = require("http");
url = require('url')

另外请记住,您可以使用https模块在安全的网络上进行通信。所以这两条线会改变:

https = require("https");
...
https.get(url.format(requestUrl), (resp) => { ......

尝试使用简单的http。Get (options, callback)函数在node.js:

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);
});

还有一个通用的http。请求(选项,回调)函数,允许您指定请求方法和其他请求细节。