我正在使用express通过 Node 开发REST API。当我尝试运行我的应用程序时,出现此错误:
TypeError: Router.use() requires middleware function but got a Object at Function.use (/Users/....../Desktop/NodeProjects/MyWebsite/node_modules/express/lib/router/index.js:458:13) at EventEmitter.<anonymous> (/Users/......./Desktop/NodeProjects/MyWebsite/node_modules/express/lib/application.js:219:21) at Array.forEach (native) at EventEmitter.use (/Users/........./Desktop/NodeProjects/MyWebsite/node_modules/express/lib/application.js:216:7) at Object.<anonymous> (/Users/............./Desktop/NodeProjects/MyWebsite/app.js:32:5) at Module._compile (module.js:398:26) at Object.Module._extensions..js (module.js:405:10) at Module.load (module.js:344:32) at Function.Module._load (module.js:301:12) at Function.Module.runMain (module.js:430:10)
下面是我的代码:
app.js
代码
var express = require('express');
var http = require('http');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var nodemailer = require('nodemailer');
var url = require('url');
var routes = require('./routes/index');
var contacts = require('./routes/contacts');
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.set('port', process.env.PORT || 3000);
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', routes);
app.use('/contacts', contacts);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
app.get('/contacts',function(request, response){
var get_params = url.parse(request.url, true).query;
if (Object.keys(get_params).length == 0)
{
response.setHeader('content-type', 'application/json');
response.end(JSON.stringify(contacts.list()));
}
else
{
response.setHeader('content-type', 'application/json');
stringify(contacts.query_by_arg(get_params.arg, get_params.value));
}
});
http.createServer(app).listen(app.get('port'), function() {
console.log('Express server listening on port ' + app.get('port'));
});
module.exports = app;
Contacts.js
的代码
var fs = require('fs');
//Read Json file
function read_json_file() {
var file = './data/contacts.json';
return fs.readFileSync(file);
}
//Parse the the file da
exports.list = function() {
return JSON.parse(read_json_file());
};
exports.query = function(number) {
var json_result = JSON.parse(read_json_file());
var result = json_result.result;
for (var i = 0; i < result.length; i++) {
var contact = result[i];
if (contact.primarycontactnumber === number) {
return contact;
}
}
return null;
};
exports.query_by_arg = function(arg, value) {
var json_result = JSON.parse(read_json_file());
var result = json_result.result;
for (var i = 0; i < result.length; i++) {
var contact = result[i];
if (contact[arg] === value) {
return contact;
}
}
return null;
};
exports.list_groups = function() {
var json_result = JSON.parse(read_json_file());
var result = json_result.result;
var resultArray = [];
for (var i = 0; i < result.length; i++) {
var groups = result[i].groups;
for (var index = 0; index < groups.length; index++) {
if (resultArray.indexOf(groups[index]) === -1) {
resultArray.push(groups[index]);
}
}
}
return resultArray;
};
exports.get_members = function(group_name) {
var json_result = JSON.parse(read_json_file());
var result = json_result.result;
var resultArray = [];
for (var i = 0; i < result.length; i++) {
if (result[i].groups.indexOf(group_name) > -1) {
resultArray.push(result[i]);
}
}
return resultArray;
};
当我注释掉 app.js
中的 app.use('/contacts', contacts);
行时,它可以正常工作。否则我会遇到这个问题。我做了很多尝试来探究其背后的原因,但都失败了。任何人都可以帮我解决这个问题吗?
最佳答案
根据 docs , app.use
用于注册中间件;您的 contacts.js 不包含任何中间件,它只包含您在实际 /contacts 路由中使用的辅助函数。
正如您所指出的,将其注释掉可以使一切正常工作。无需做任何其他事情:)
您还需要将 404 处理程序移至路线之后,否则它将在每条路线之前运行,因此会出现您看到的 404。请参阅error handling文档以获取更多信息。
关于node.js - TypeError : Router. use() 需要中间件函数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34704978/