Question

尝试确保在呈现页面之前完成请求

应用程序概述 - 使用代码提交，发出请求，填充结果页面

// Index.js

var response = require('./requestMapping')

// home search page
exports.index = function(req, res){
  res.render('index', { stationDisplay: response.station_id, test: 'rob' });
};

**//post from form to call METAR service
exports.post =('/', function(req, res, next) {
  response.getMETAR(req.body.query,function(){
    res.render('results', {
        stationDisplay: response.station_id,
        test: 'rob'
    });
  });
})**

// Index.ejs

<!DOCTYPE html>
<html>
  <head>
    <title><%= stationDisplay %></title>
    <link rel='stylesheet' href='/stylesheets/style.css' />
  </head>
  <body>
    <h1>Enter ICAO code to get the latest METAR</h1>
    <form method="post" action="/">
        <input type="text" name="query">
        <input type="submit">
    </form>
  </body>
</html>

调用webservice的模块 - requestMapping.js

/**
 * @author robertbrock
 */
//Webservice XML
function getMETAR(ICAO){

    var request = require('request');
    request('http://weather.aero/dataserver_current/httpparam?datasource=metars&requestType=retrieve&format=xml&mostRecentForEachStation=constraint&hoursBeforeNow=24&stationString='+ICAO, function(error, response, body){
        if (!error && response.statusCode == 200) {
            var XmlDocument = require('xmldoc').XmlDocument;
            var results = new XmlDocument(body);

            console.log(body)
            console.log(ICAO)
            exports.station_id = results.valueWithPath("data.METAR.station_id");
//etc.

        }
    })
}
exports.getMETAR =getMETAR;

Answer 1

我看不出你的getMETAR函数实际上是否需要回调函数？我希望它是：

function getMETAR(ICAO, callback) {
    // Do your work
    var station_id = results.valueWithPath("data.METAR.station_id");
    callback(null, station_id); // It's common to use the first arg of the callback if an error has occurred
}

然后调用此函数的代码可以像这样使用它：

app.post('/', function(req, res) {
    response.getMETAR(req.body.query, function(err, station_id) {
        res.render('results', {stationDisplay: station_id, test: 'rob'};
    });
});

需要一些时间来习惯异步编程以及回调如何工作，但是一旦你完成了几次，你就可以了解它。

Answer 2

如果没有看到其余的代码，很难猜到，但您的代码看起来应该更像：

app.post('/', function(req, res, next) {
  response.getMETAR(req.body.query,function(){
    res.render('results', {
        stationDisplay: response.station_id,
        test: 'rob'
    });
  });
});

努力回调工作express.js

2 个答案: