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Here Is my MongoDB backend code

 var mongo = require("mongodb");
 var DbHost = "127.0.0.1";
 var DbPort = mongo.Connection.DEFAULT_PORT;


  module.exports.list = list;

  var db = new mongo.Db("ferrari-db",new mongo.Server(DbHost,DbPort,{}),{safe:true});
  var collectionName  = "carsList";


  function list(req,res,callback){

     db.open(function(error){
        db.collection(collectionName,function(error,collection){
           console.log("have the collection");
           collection.find().toArray(function(error,data){
               if (error) callback(false);
                else{
                   callback(true);
                   console.log(data);
                   res.json(data);

                  }
             });

          });
      });
   }

Here is my Node.js express code

   var express = require('express');
   var http = require('http');
   var path = require('path');
   var cars = require('./server/api/cars.js')

   var app = express();

   var client_dir =  path.join(__dirname, '/client')
   // all environments
   app.set('port', process.env.PORT || 3000);
   app.use(express.favicon());
   app.use(express.logger('dev'));
   app.use(express.bodyParser());
   app.use(app.router);
   app.use(express.static(client_dir));


   // development only
   if ('development' == app.get('env')) {
        app.use(express.errorHandler());
    }

   app.get('/', function(req,res){
       res.sendfile(path.join(client_dir,'index.html'))

    });

    app.get('/api/cars',cars.list);

    http.createServer(app).listen(app.get('port'), function(){
         console.log('Express server listening on port ' + app.get('port'));
    });

Here is my angularJs app.js code

var CarApp = angular.module('CarApp',['ngResource'])

CarApp.config(function($routeProvider){
    $routeProvider
        .when('/',{controller:ListCtrl,templateUrl:'partials/list.html'})
         .otherwise({redirectTo:'/'})

 }) ;

 CarApp.factory('Cars',function($resource){
      return $resource('/api/cars/:id',{id:'@id'},{update:{method:'PUT'}})
 });

 function ListCtrl ($scope,Cars){

     $scope.cars = Cars.query();

 }

Here is index.html file 

   <!DOCTYPE html>
  <html>
  <meta charset="utf-8">
  <title>Ferrari</title>


 <link type="text/css" rel= "stylesheet" href="vendor/bootstrap/css/bootstrap.css"/>
 <script src="vendor/bootstrap/js/bootstrap.js"></script>
 <script src="vendor/angular.min.js"></script>
 <script src="vendor/angular-resource.min.js"></script>
 <script src="js/app.js"></script>

 <body>
 <h1>Hello</h1>

      <div ng-app="CarApp" class="container">
           <div ng-view>
            </div>
      </div>
  </body>

  </html>

here is my list.html file

 <table class= "table table-bordered table-hover">
  <thead>
      <th>Type</th>
      <th>Mileage</th>
      <th>Year</th>
      <th>Price</th>
  </thead>

<tr ng-repeat="car in cars">
    <td>{{ car.title }}</td>
    <td>{{ car.mileage }}</td>
    <td>{{ car.year }}</td>
    <td>{{ car.price }}</td>
</tr>

</table>

The list.html template is loading . I get the error Failed to load resource: the server responded with a status of 500 (Internal Server Error) ? Also i get the error Error: Can't set headers after they are sent. I can log out the data in console in list method. Any help would be highly appreciable?

4

1 回答 1

1

您的问题在cars.list函数内部。

Express 路由的结构如下function myRoute(req, res, next) {...}。
该next功能（或callback如您所说）仅在中间件中有另一个功能时才有用。
也许errorHandler中间件之后被调用（app.get('/api/cars', cars.list);），我不确定。

问题可能是您调用callback(true)which 启动下一个中间件（并使用headers发送响应等），然后尝试使用res.json(...).
你需要放下callback(true)。

所以我认为你应该像这样重写你的函数：

function list(req, res, next) {

  db.open(function (error) {
    db.collection(collectionName, function (error, collection) {
      console.log('Have the collection');
      collection.find().toArray(function(error,data){
        if (error) {
          // Hopefully we pass the error to the error handler
          return next(error);
        } else {
          // If everything goes fine we send the data.
          console.log(data);
          return res.json(data);
        }
      });
    });
  });
}
于 2013-09-13T17:56:00.490 回答