[英]Cannot call method 'send' of undefined(response is undefined) in express js
I have tried to pass a variable from my index.html to the database(maildata.js) through app.js(server) and get the corresponding data I am able to get the data from the database but couldnt send that back to the server(app.js) 我试图通过app.js(server)将变量从index.html传递到数据库(maildata.js)并获取相应的数据,我能够从数据库中获取数据,但无法将其发送回服务器(app.js)
app.js app.js
var express = require('express');
var maildata= require('./maildata');
var app = express();
app.configure(function(){
app.use(express.bodyParser());
});
app.get('/', function(request, response){
response.sendfile(__dirname + '/mailbox.html');
});
app.post('/mailboxpost',function(request, response) {
var input=request.query.search;
var result=maildata.getMailData(input);
response.send(result);
response.end();
});
app.listen(8888);
console.log('Server is running on port 8888');
maildata.js maildata.js
exports.getMailData=function(data,response) {
var stop_name= data;
connection.query("select stop_name,stop_comment from stoplist where stop_name= '"+stop_name+"' limit 1",function(err, rows) {
if (err) {
console.log('error in fetching ' + err);
}
else{
var jsonString1= JSON.stringify(rows);
connection.query("select mailbox_sequence_no from stoplist where stop_name= '"+stop_name+"'",function(err, rows) {
if (err) {
console.log('error in fetching ' + err);
}
else{
var jsonString2 = JSON.stringify(rows);
connection.query("select party_head from stoplist where stop_name= '"+stop_name+"'", function(err, rows) {
if (err) {
console.log('error in fetching ' + err);
}
else{
var jsonString3 = JSON.stringify(rows);
var result=jsonString1+'/'+jsonString2+'/'+jsonString3;
response.send(result);
}
});
}
});
}
});
}
Thanks in Advance 提前致谢
调用函数时如何发送响应?
var result=maildata.getMailData(input); // something missing here
Your getMailData
function expects two arguments: 您的getMailData
函数需要两个参数:
exports.getMailData=function(data,response) { ... }
but you give it only one: 但您只给它一个:
var result=maildata.getMailData(input);
Which makes the value of the response
argument undefined
. 这使得response
参数的值undefined
。
Here is what you should do: 这是您应该做的:
app.post('/mailboxpost',function(request, response) {
var input=request.query.search;
maildata.getMailData(input, response);
});
and let maildata.getMailData
handle the response sending, as you did in response.send(result);
并让maildata.getMailData
处理响应发送,就像您在response.send(result);
所做的一样response.send(result);
I have used asynchronous callback method in my app.js. 我在我的app.js中使用了异步回调方法。
I got the result 我得到了结果
var result=maildata.getMailData(input,response,function(data){
response.send(data);
response.end();
});
Thanks all 谢谢大家
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