Question

我有一些功能，第一个从yahoo财务服务器获取一个值，然后我用这个值更新数据库，我正在使用async.queue和async.waterfall这样做问题是我的数据库连接从未关闭，我是node.js的新手，所以如果你能够提供一些例子，我会非常感激。这是我的代码：

var request = require('request');
var cheerio = require ('cheerio');
var fs = require('fs');
var MongoClient = require('mongodb').MongoClient;
var async  =  require('async');

var dbName = "ystocks";
var port = "27017";
var requiredCollection = "stocks"
var host = "localhost";


MongoClient.connect("mongodb://" + host + ":" + port + "/" + dbName, function (error, db){

    console.log("Connection is opened to : " + "mongodb://" + host + ":" + port + "/" + dbName);

    var q = async.queue(function (doc, callback) {
  // code for your update

            var stockName = doc.ticker;
            var stockValue =  doc.value;

            var yUrl = "http://finance.yahoo.com/q/ks?s=" + stockName;
            console.log("The url is : " + yUrl);


            updateStock(doc.ticker, yUrl, db, function(error) {
            if (error) {
                console.log("There was an error");
                console.error(error);

            }
            else {
                console.log("Done updating");

            }
            }) 



    }, Infinity);

var cursor = db.collection(requiredCollection).find();
cursor.each(function(err, doc) {
  if (err) throw err;
  if(doc!=null) {
  q.push(doc); // dispatching doc to async.queue
} 
});

q.drain = function() {
  if (cursor.isClosed()) {
    console.log('all items have been processed');
    // console.log("printinhg thr array:") 
    // for (var i=0; i<arr2.length; i++) {
    //  console.log(arr2[i]);
    // }
    db.close();
  }
}

 }); // end of connection to MongoClien





function updateStock(stockName, yUrl, db, callback) {
    async.waterfall([

        function getStockvalue(getStockvalueCallback) {
            request(yUrl, stockName,  function (error, response, body) {
                var date  = setTimeToLocal(new Date(), 3);
                if (!error && response.statusCode == 200) {         
                    var $ =  cheerio.load(body);                    

                    // the keys - We get them from a certain class attribute
                    var span =  $('.time_rtq_ticker>span');
                    var stockValue = $(span).text();

                    // parsing the value to a number in case it was a String
                    var parsedValue = parseFloat(stockValue);
                //  console.log("checking the type of the stockValue " +  typeof(parsedValue) + " " + parsedValue);

                    // Calling the setStockValue function which will update the stock value
                //  setStockValue(stockName, parsedValue, callback, db);

                    console.log("Response received from -> " + yUrl);
                    console.log(date);
                    console.log("Stock  - " + stockName + " --> " + stockValue ); 
                    getStockvalueCallback (null, stockValue );

                }//end of !error && response.statusCode == 200
                else if (response.statusCode == 404){
                    console.log("Response failed from " + yUrl + " --> error code:  " +  response.statusCode);
                    getStockvalueCallback(error);
                }//end of statusCode == 400
            }); // end of request 

        }, // end of getStockvalue

        function setStockValueInDB (stockValue,setStockValueInDBCallback) {
            var query = {'ticker' : stockName};
            var operator ={'$set' : {'value' : stockValue}};
            // update a specific documnet
            db.collection('stocks').update(query, operator, callback);
            console.log(stockName + " Updated successfully")
            setStockValueInDBCallback(null);

        } // end of setStockValueInDB

        ], callback); //  end of waterfall


} // end of updateStock


// Gets the local date and the desired offset time
    // set 
    function setTimeToLocal(date, offset ) {
        // getting the local tome in millseconds 
            var localtime = date.getTime();

            // getting the local offset in millseconds
            var localOffset = date.getTimezoneOffset()*60000;

            var utc = localOffset + localtime;

            // Jerusalem offset
            //  var offset = 3;

            // Jerusalem time in millseconds
            var jerusalem =  utc + (offset*3600000);
            var d = new Date(jerusalem);
            //console.log("Jerusalem Local Time: " + d.toLocaleString());
            return d;
    } // end of SetTimeToLocal

Answer 1

好的，所以我将回调传递给更新功能时遇到了问题我改了它，这是我的新工作代码：

var request = require('request');
var cheerio = require ('cheerio');
var fs = require('fs');
var MongoClient = require('mongodb').MongoClient;
var async  =  require('async');

var dbName = "ystocks";
var port = "27017";
var requiredCollection = "stocks"
var host = "localhost";


MongoClient.connect("mongodb://" + host + ":" + port + "/" + dbName, function (error, db){

    console.log("Connection is opened to : " + "mongodb://" + host + ":" + port + "/" + dbName);

    var q = async.queue(function (doc, callback) {
  // code for your update

            var stockName = doc.ticker;
            var stockValue =  doc.value;

            var yUrl = "http://finance.yahoo.com/q/ks?s=" + stockName;
            console.log("The url is : " + yUrl);


            updateStock(doc.ticker, yUrl, db,callback, function(error) {
            if (error) {
                console.log("There was an error");
                console.error(error);

            }
            else {
                console.log("Done updating");

            }
            }) 



    }, Infinity);

var cursor = db.collection(requiredCollection).find();
cursor.each(function(err, doc) {
  if (err) throw err;
  if(doc!=null) {
  q.push(doc); // dispatching doc to async.queue
} 
});

q.drain = function() {
  if (cursor.isClosed()) {
    console.log('all items have been processed');
    // console.log("printinhg thr array:") 
    // for (var i=0; i<arr2.length; i++) {
    //  console.log(arr2[i]);
    // }
    db.close();
  }
}

 }); // end of connection to MongoClien





function updateStock(stockName, yUrl, db, callback, cb) {
    async.waterfall([

        function getStockvalue(getStockvalueCallback) {
            request(yUrl, stockName,  function (error, response, body) {
                var date  = setTimeToLocal(new Date(), 3);
                if (!error && response.statusCode == 200) {         
                    var $ =  cheerio.load(body);                    

                    // the keys - We get them from a certain class attribute
                    var span =  $('.time_rtq_ticker>span');
                    var stockValue = $(span).text();

                    // parsing the value to a number in case it was a String
                    var parsedValue = parseFloat(stockValue);
                //  console.log("checking the type of the stockValue " +  typeof(parsedValue) + " " + parsedValue);

                    // Calling the setStockValue function which will update the stock value
                //  setStockValue(stockName, parsedValue, callback, db);

                    console.log("Response received from -> " + yUrl);
                    console.log(date);
                    console.log("Stock  - " + stockName + " --> " + stockValue ); 
                    getStockvalueCallback (null, parsedValue);

                }//end of !error && response.statusCode == 200
                else if (response.statusCode == 404){
                    console.log("Response failed from " + yUrl + " --> error code:  " +  response.statusCode);
                    getStockvalueCallback(error);
                }//end of statusCode == 400
            }); // end of request 

        }, // end of getStockvalue
        function readFile(parsedValue, readFileCallback) {
            fs.readFile('stocktest.json', function(error,  file) {
            if (error) {
                console.error(error);
                readFileCallback(error);
            }
            else {
                console.log("The value from readFile function -- " + parsedValue );
                readFileCallback (null, file, parsedValue);
            }
            }); // end of fs.readFile

        }, // end of readfile
        function processFile(file, parsedValue, processFileCallback) {
            var stocksJson =  JSON.parse(file);

            if (stocksJson[stockName]!=null) {
                console.log(stockName+" price : " + stocksJson[stockName].price);
                console.log("changing the value...")
                stocksJson[stockName].price =  parsedValue;
                console.log("Price after the change has been made -- " + stocksJson[stockName].price);
                console.log("printing the the Json.stringify")
                console.log(JSON.stringify(stocksJson, null, 4));
                 fs.writeFile('stocktest.json',JSON.stringify(stocksJson, null, 4) , function(error) {  
                                if(!error) {
                                    console.log("File Successfully Written");
                                    console.log("The value from processFile func -- " + parsedValue);
                                    processFileCallback(null, parsedValue);
                                }
                                if (error) {
                                    console.error(error);
                                    processFileCallback(error);
                                }

                           }); // end of writeFile
            }
            else {
                console.log(stockName + " doesn't exist on the json");
                processFileCallback(null);
            }
        }, //  end of processFile


        function setStockValueInDB (parsedValue,setStockValueInDBCallback) {
            var query = {'ticker' : stockName};
            var operator ={'$set' : {'value' : parsedValue}};
            // update a specific documnet
            db.collection('stocks').update(query, operator, callback);
            console.log(stockName + " Updated successfully")
            setStockValueInDBCallback(null);

        } // end of setStockValueInDB

        ], cb); //  end of waterfall


} // end of updateStock


// Gets the local date and the desired offset time
    // set 
    function setTimeToLocal(date, offset ) {
        // getting the local tome in millseconds 
            var localtime = date.getTime();

            // getting the local offset in millseconds
            var localOffset = date.getTimezoneOffset()*60000;

            var utc = localOffset + localtime;

            // Jerusalem offset
            //  var offset = 3;

            // Jerusalem time in millseconds
            var jerusalem =  utc + (offset*3600000);
            var d = new Date(jerusalem);
            //console.log("Jerusalem Local Time: " + d.toLocaleString());
            return d;
    } // end of SetTimeToLocal

使用node.js更新mongoDB中的文档

1 个答案: