Question

有问题的代码是app.use(express.static("web"))行。

var express = require('express')();
var app = express();
var http = require('http').Server(app);
var io = require('socket.io')(http);

//app.get('/', function(res, req) {
//	res.sendFile(__dirname + '/www/index.html');
//})

app.use(express.static("web"));

在控制台中返回以下错误：

/Users/matthewwalker/CVLGBT/CVLGBT/www/node_modules/finalhandler/index.js:92
    if (!err && res._header) {
                    ^

TypeError: Cannot read property '_header' of undefined
    at /Users/matthewwalker/CVLGBT/CVLGBT/www/node_modules/finalhandler/index.js:92:21
    at Function.handle (/Users/matthewwalker/CVLGBT/CVLGBT/www/node_modules/express/lib/application.js:170:5)
    at app (/Users/matthewwalker/CVLGBT/CVLGBT/www/node_modules/express/lib/express.js:38:9)
    at Object.<anonymous> (/Users/matthewwalker/CVLGBT/CVLGBT/www/index.js:2:11)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)

其他时候我稍微修改代码会得到express is not defined。文件结构：index.js和节点模块在根目录下，而所有html / css / js / imgs在/ web下。我不确定为什么会引发此标头标志。当我使用app.get行时，它仅发送html文件，而不发送图像或js。我需要能够提供/ web的整个目录。

Answer 1

您要在第一行中构建一个import math class Vector: def __init__(self,x,y): self.x= x self.y =y def add(self,other): new_x = self.x + other.x new_y = self.y + other.y return Vector(new_x,new_y) def subtract(self,other): new_x = self.x - other.x new_y = self.y - other.y return Vector(new_x,new_y) def scale(self,factor): new_x = self.x * factor new_y = self.y * factor return Vector(new_x,new_y) def length(self,other): r_squared = self.x ** 2 + self.y **2 return Vector(r_squared)实例，然后在第2行中调用它：

app

您应该改为这样做：

var express = require('express')();
var app = express();

或者这个：

var express = require('express');
var app = express();

您可以找到有关express api here的更多信息。

无法读取未定义的属性“ _header”

1 个答案: