Javascript 为什么我的变量没有在node.js中更新?
我已经用node.js构建了一个webapp,通过POST请求接收来自SNS主题的消息,并将它们记录到控制台,然后将它们显示在网页上。如果我发布消息到我的主题,我会在控制台中打印消息,但网页上没有更新 这是我的Javascript 为什么我的变量没有在node.js中更新?,javascript,node.js,embedded-javascript,Javascript,Node.js,Embedded Javascript,我已经用node.js构建了一个webapp,通过POST请求接收来自SNS主题的消息,并将它们记录到控制台,然后将它们显示在网页上。如果我发布消息到我的主题,我会在控制台中打印消息,但网页上没有更新 这是我的app.js const express = require("express"); const request = require('request') const bodyParser = require('body-parser') const app = express(); ap
app.js
const express = require("express");
const request = require('request')
const bodyParser = require('body-parser')
const app = express();
app.use(express.static('public'));
app.set("view engine", "ejs")
app.get('/', function (req, res) {
let subject = "Your Subject Will Appear Here";
let message = "Your Message Will Appear Here";
res.render("index", {subject:subject, message:message});
})
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())
app.post('/', (req, res) => {
let body = ''
req.on('data', (chunk) => {
body += chunk.toString()
})
req.on('end', () => {
let payload = JSON.parse(body)
if (payload.Type === 'Notification') {
console.log(payload.Message);
let subject = payload.Subject;
let message = payload.Message;
res.render("index", {subject:subject, message:message});
}
});
});
app.listen(80, process.env.IP, function(request, response){
console.log("## SERVER STARTED ##");
});
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>title</title>
<link rel="stylesheet" type="text/css" href="/css/style.css">
<link href='https://fonts.googleapis.com/css?family=Open+Sans:300' rel='stylesheet' type='text/css'>
</head>
<body>
<div class="container">
<fieldset>
<% if(subject !== null){ %>
<p>SNS Subject: <%= subject %></p>
<% } %>
<% if(message !== null){ %>
<p>SNS Message: <%= message %></p>
<% } %>
</fieldset>
</div>
</body>
</html>
这是我的index.js的代码
const express = require("express");
const request = require('request')
const bodyParser = require('body-parser')
const app = express();
app.use(express.static('public'));
app.set("view engine", "ejs")
app.get('/', function (req, res) {
let subject = "Your Subject Will Appear Here";
let message = "Your Message Will Appear Here";
res.render("index", {subject:subject, message:message});
})
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())
app.post('/', (req, res) => {
let body = ''
req.on('data', (chunk) => {
body += chunk.toString()
})
req.on('end', () => {
let payload = JSON.parse(body)
if (payload.Type === 'Notification') {
console.log(payload.Message);
let subject = payload.Subject;
let message = payload.Message;
res.render("index", {subject:subject, message:message});
}
});
});
app.listen(80, process.env.IP, function(request, response){
console.log("## SERVER STARTED ##");
});
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>title</title>
<link rel="stylesheet" type="text/css" href="/css/style.css">
<link href='https://fonts.googleapis.com/css?family=Open+Sans:300' rel='stylesheet' type='text/css'>
</head>
<body>
<div class="container">
<fieldset>
<% if(subject !== null){ %>
<p>SNS Subject: <%= subject %></p>
<% } %>
<% if(message !== null){ %>
<p>SNS Message: <%= message %></p>
<% } %>
</fieldset>
</div>
</body>
</html>
标题
SNS主题:
SNS消息:
因为您的变量是get
和post
回调函数中的local变量。如果希望它们在这些回调的作用域之外持久存在,则需要将它们移动到回调返回时不会消失的作用域
例如,这使得他们可以使用模块globals,但是对于每个帖子来说,不管它来自谁,更改不相关get的内容似乎都很奇怪(请参见***
注释):
//***在模块范围内声明
let subject=“您的主题将出现在此处”;
let message=“您的消息将显示在此处”;
app.get('/',函数(req,res){
//***此处未声明
res.render(“索引”{subject:subject,message:message});
})
// ...
应用程序发布(“/”,(请求,回复)=>{
让body=''
请求on('数据',(块)=>{
body+=chunk.toString()
})
请求开启('end',()=>{
让payload=JSON.parse(body)
如果(payload.Type===‘通知’){
console.log(payload.Message);
subject=payload.subject;//谢谢!这很有意义,我最近才开始使用来自Python的NodeJ,我甚至没有考虑范围!