从函数内发出 http 请求 - Node.js

Question

我正在节点中编写 Web 服务，我是回调概念的新手。我的路由文件中有一个接收 url 参数的路由 - 一个 Facebook 访问令牌，并且应该调用 getMP 函数。此函数创建对 Facebook 的 http 请求并检索一些我想稍后处理的信息。所以路线看起来像这样：

//route that recives parameter using defined parameters - enter FB access token to get  music info about it
app.get('/MP/:FBat', 
    function (req, res, next){
        res.header("Access-Control-Allow-Origin", "*");
        res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        next(); 
    },

    function (req, res) {
    res.status(200).json(FB.getMP(req.params.FBat));
});

和函数 getMP :

exports.getMP = function(access_token) {
request("https://graph.facebook.com/v2.5/me/music?access_token=" + access_token, function(error, response, body) {
    if (!error && response.statusCode == 200) {
        FB_MP = JSON.parse(body);
        // console.log(FB_MP); this returns ok
      }else{
        console.log(response.statusCode);
      }
    });

//return value - I wand to use it after the request has returned
return FB_MP;
}

正确的做法是什么？如果 res 很快，它就可以工作，但当然不好。有什么建议吗？谢谢

Answer 1

你可以使用像 q 这样的承诺库，并在方法 then 中获得必要的值后做出响应，试试这样的事情：

//route that receives parameter using defined parameters - enter FB access    token to get  music info about it
app.get('/MP/:FBat', 
    function (req, res, next){
        res.header("Access-Control-Allow-Origin", "*");
        res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        next(); 
    },

    function (req, res) {
        FB.getMP(req.params.FBat)
        .then(function(result){
            if(result){
                res.status(200).json(result);
            }
            else{
               console.log('do something about it');
            }
        });            
});

getMP 的代码将是这样的：

var Q = requirie('q');
exports.getMP = function(access_token) {
    var deferred = Q.defer();
    request("https://graph.facebook.com/v2.5/me/music?access_token=" +  access_token, function(error, response, body) {
     if (!error && response.statusCode == 200) {
        FB_MP = JSON.parse(body);
        deferred.resolve(FB_MP);
      }else{
        deferred.resolve(false);
      }
    });

    //return value - I wand to use it after the request has returned
    return deferred.promise;
}

您还可以将 req 和 res 参数传递给您放置逻辑的一种控制器，然后将结果发送到视图。像这样：

//route that receives parameter using defined parameters - enter FB access  token to get  music info about it
var controller = require('path/to/controller');
app.get('/MP/:FBat', 
    function (req, res, next){
        res.header("Access-Control-Allow-Origin", "*");
        res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        next(); 
    },

    function (req, res) {
        controller.getFacebookAccess(req, res, req.params.FBat);
});

控制器：

module.exports = function getFacebookAccess(req, res, access_token){
    request("https://graph.facebook.com/v2.5/me/music?access_token=" +  access_token, function(error, response, body) {
        if (!error && response.statusCode == 200) {
            FB_MP = JSON.parse(body);
            res.status(200).json(FB_MP);
          }else{
            res.send('do something about it');
          }
        });
    }
};

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