[英]Handling a GET request in Node.js Express server: res.render(file.ejs, data) not working because data is not defined
In a server made with Express in Node.js, I have the following code for handling a GET request: 在Node.js中使用Express制造的服务器中,我具有以下代码来处理GET请求:
function articleReturner(celien) { // function querying a database (celien is a string, cetarticle is a JSON)
Article.findOne({ lien: celien}, function (err, cetarticle){
console.log(cetarticle); // it works
return cetarticle;
});
}
app.get('/selection/oui/', function(req, res) { // the URL requested ends with ?value=http://sweetrandoms.com, for example
var celien = req.param("value"); //
console.log(celien); // it works
articleReturner(celien); // calling the function defined above
res.render('selection_form.ejs', cetarticle); // doesn't work!
});
I know that data from the URL routing is correctly obtained by the server since the console correctly displays celien
(a string). 我知道服务器从URL路由中正确获取了数据,因为控制台正确显示了
celien
(字符串)。 I also know that the function articleReturner(celien)
is correctly querying the database because the console correctly displays cetarticle
(a JSON). 我也知道
function articleReturner(celien)
正在正确查询数据库,因为控制台正确显示了cetarticle
(JSON)。
But res.render('selection_form.ejs', cetarticle);
但是
res.render('selection_form.ejs', cetarticle);
is not working and the console displays ReferenceError: cetarticle is not defined
... What am I missing? 无法正常工作,并且控制台显示
ReferenceError: cetarticle is not defined
...我缺少什么? Thanks! 谢谢!
Function articleReturner is executed asynchronously and return cetarticle;
函数
return cetarticle;
异步执行并return cetarticle;
doesn't make a lot of sense. 没有任何意义。 You need to use callbacks or promises.
您需要使用回调或Promise。 Here is the code that uses callback to return result from articleReturner:
这是使用回调从articleReturner返回结果的代码:
function articleReturner(celien, callback) {
Article.findOne({ lien: celien}, function (err, cetarticle){
console.log(cetarticle);
callback(err,cetarticle);
});
}
app.get('/selection/oui/', function(req, res) {
var celien = req.param("value"); //
console.log(celien); // it works
articleReturner(celien, function(err, cetarticle){
res.render('selection_form.ejs', cetarticle);
});
});
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.