我的问题可能非常愚蠢,因为我在网络开发和nodejs方面都是全新的。
我按照这里的明确解释 - > http://expressjs.com/en/starter/generator.html
表示如何生成应用程序框架。 一旦我启动应用程序,我看看shell,我有一个无限的消息 GET / json 404:screenshot 我还没有请求任何网址(http://localhost:3000/除外)因此让我感到困惑。 我在完成快速教程步骤后立即得到了这个问题(参见上面的链接)。尝试不同的方法(在应用程序中设置端口监听,通过节点检查运行等)后,我仍然得到相同的消息,因为它是无限循环。这是正常的吗?也许这篇文章回答了我的问题:http://jilles.me/getting-the-express-app-js/(名为"特殊404错误"),其中似乎404并不一定意味着错误。
尽管如此,我想100%确定这是好的,这样我就不会从头开始编程错误。
非常感谢您的帮助。
请参阅以下代码生成的代码:
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', indexRouter);
app.use('/users', usersRouter);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
next(createError(404));
});
// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
// These lines are mines but they haven't solved the issue
/* ------------------------------------------------- */
app.set('port', process.env.PORT || 3000);
var server = app.listen(app.get('port'));
/* ------------------------------------------------- */
module.exports = app;
这是' http-errors'模块,如果需要:
/*!
* http-errors
* Copyright(c) 2014 Jonathan Ong
* Copyright(c) 2016 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module dependencies.
* @private
*/
var deprecate = require('depd')('http-errors')
var setPrototypeOf = require('setprototypeof')
var statuses = require('statuses')
var inherits = require('inherits')
/**
* Module exports.
* @public
*/
module.exports = createError
module.exports.HttpError = createHttpErrorConstructor()
// Populate exports for all constructors
populateConstructorExports(module.exports, statuses.codes, module.exports.HttpError)
/**
* Get the code class of a status code.
* @private
*/
function codeClass (status) {
return Number(String(status).charAt(0) + '00')
}
/**
* Create a new HTTP Error.
*
* @returns {Error}
* @public
*/
function createError () {
// so much arity going on ~_~
var err
var msg
var status = 500
var props = {}
for (var i = 0; i < arguments.length; i++) {
var arg = arguments[i]
if (arg instanceof Error) {
err = arg
status = err.status || err.statusCode || status
continue
}
switch (typeof arg) {
case 'string':
msg = arg
break
case 'number':
status = arg
if (i !== 0) {
deprecate('non-first-argument status code; replace with createError(' + arg + ', ...)')
}
break
case 'object':
props = arg
break
}
}
if (typeof status === 'number' && (status < 400 || status >= 600)) {
deprecate('non-error status code; use only 4xx or 5xx status codes')
}
if (typeof status !== 'number' ||
(!statuses[status] && (status < 400 || status >= 600))) {
status = 500
}
// constructor
var HttpError = createError[status] || createError[codeClass(status)]
if (!err) {
// create error
err = HttpError
? new HttpError(msg)
: new Error(msg || statuses[status])
Error.captureStackTrace(err, createError)
}
if (!HttpError || !(err instanceof HttpError) || err.status !== status) {
// add properties to generic error
err.expose = status < 500
err.status = err.statusCode = status
}
for (var key in props) {
if (key !== 'status' && key !== 'statusCode') {
err[key] = props[key]
}
}
return err
}
/**
* Create HTTP error abstract base class.
* @private
*/
function createHttpErrorConstructor () {
function HttpError () {
throw new TypeError('cannot construct abstract class')
}
inherits(HttpError, Error)
return HttpError
}
/**
* Create a constructor for a client error.
* @private
*/
function createClientErrorConstructor (HttpError, name, code) {
var className = name.match(/Error$/) ? name : name + 'Error'
function ClientError (message) {
// create the error object
var msg = message != null ? message : statuses[code]
var err = new Error(msg)
// capture a stack trace to the construction point
Error.captureStackTrace(err, ClientError)
// adjust the [[Prototype]]
setPrototypeOf(err, ClientError.prototype)
// redefine the error message
Object.defineProperty(err, 'message', {
enumerable: true,
configurable: true,
value: msg,
writable: true
})
// redefine the error name
Object.defineProperty(err, 'name', {
enumerable: false,
configurable: true,
value: className,
writable: true
})
return err
}
inherits(ClientError, HttpError)
ClientError.prototype.status = code
ClientError.prototype.statusCode = code
ClientError.prototype.expose = true
return ClientError
}
/**
* Create a constructor for a server error.
* @private
*/
function createServerErrorConstructor (HttpError, name, code) {
var className = name.match(/Error$/) ? name : name + 'Error'
function ServerError (message) {
// create the error object
var msg = message != null ? message : statuses[code]
var err = new Error(msg)
// capture a stack trace to the construction point
Error.captureStackTrace(err, ServerError)
// adjust the [[Prototype]]
setPrototypeOf(err, ServerError.prototype)
// redefine the error message
Object.defineProperty(err, 'message', {
enumerable: true,
configurable: true,
value: msg,
writable: true
})
// redefine the error name
Object.defineProperty(err, 'name', {
enumerable: false,
configurable: true,
value: className,
writable: true
})
return err
}
inherits(ServerError, HttpError)
ServerError.prototype.status = code
ServerError.prototype.statusCode = code
ServerError.prototype.expose = false
return ServerError
}
/**
* Populate the exports object with constructors for every error class.
* @private
*/
function populateConstructorExports (exports, codes, HttpError) {
codes.forEach(function forEachCode (code) {
var CodeError
var name = toIdentifier(statuses[code])
switch (codeClass(code)) {
case 400:
CodeError = createClientErrorConstructor(HttpError, name, code)
break
case 500:
CodeError = createServerErrorConstructor(HttpError, name, code)
break
}
if (CodeError) {
// export the constructor
exports[code] = CodeError
exports[name] = CodeError
}
})
// backwards-compatibility
exports["I'mateapot"] = deprecate.function(exports.ImATeapot,
'"I\'mateapot"; use "ImATeapot" instead')
}
/**
* Convert a string of words to a JavaScript identifier.
* @private
*/
function toIdentifier (str) {
return str.split(' ').map(function (token) {
return token.slice(0, 1).toUpperCase() + token.slice(1)
}).join('').replace(/[^ _0-9a-z]/gi, '')
}
答案 0 :(得分:0)
感谢generalhenry的帮助!我有自动打开的DevTools,它也对3000端口开放。我停止了它,现在它工作正常。
答案 1 :(得分:0)
它是由于开发工具而发生的。当chrome或任何其他开发工具正在监听它或开发工具中的端口转发配置时。 只需关闭开发工具,然后以开发模式(而不是调试模式)运行它,就可以像超级魅力:)