我正在编写一个 API，但我陷入了根据传入请求混合异步和同步代码的问题，请看下面的示例。
路由.js
module.exports = [
{
method: 'GET',
path: '/',
controller: 'main',
action: 'main',
description: 'lists the API functionality',
access: 'auth'
},
{
method: 'POST',
path: '/users',
controller: 'users',
action: 'create',
description: 'creates a new user',
fields: {
fullName: {
format: {
min: 2,
max: 64,
minWords: 2,
disableDoubleSpaces: true
},
description: 'the full name of the new user',
examples: 'Thomas Richards, Richard Jones, Michael J. Fox, Mike Vercoelen, John Johnson'
},
email: {
format: {
min: 2,
max: 64,
maxWords: 1,
match: 'email'
},
description: 'the email address of the new user',
examples: 'mike@grubt.com, lilly@gmail.com, thomas.richards@mail.com, peter@mymail.com'
},
password: {
format: {
min: 2,
max: 64
},
description: 'the password of the new user',
examples: '123abcdfg, 7373kEjQjd, #8klKDNfk'
}
}
}
];
routes.js 文件基本上是 API 的一个非常重要的部分，它验证传入的数据，路由到正确的控制器/动作，并定义该方法是公共的，还是需要身份验证（基本身份验证）。
api-server.js
var http = require('http');
var url = require('url');
var os = require('os');
var dns = require('dns');
var apiServer = module.exports;
var routes = require('./routes.js'); // Routes file from above.
var req, res, controller, action, serverInfo, httpServer;
apiServer.start = function(){
prepare(function(){
httpServer = http.createServer(handleRequest).listen(3000);
});
};
//
// We need to do this function, we need the local ip address of the
// server. We use this local ip address in logs (mongoDb) so we can
// refer to the correct server.
//
function prepare(callback){
var serverName = os.hostname();
dns.lookup(serverName, function(error, address){
if(error){
throw error;
}
serverInfo = {
name: serverName,
address: address
};
callback();
});
}
function getRoute(){
// loops through routes array, and picks the correct one...
}
function getAuth(callback){
// parses headers, async authentication (mongoDB).
}
function getRequestData(callback){
// req.on('data') and req.on('end'), getting request data.
}
function parseRequestData(callback){
// parse request data at this point.
}
function validateRequestData(callback){
// loop through route fields (see routes.js) and validate this data with the ones
// from the request.
}
function requireControllerAndCallAction(){
// do actual job.
}
function handleRequest(request, response){
req = request;
res = response;
req.route = getRoute(); // First step for a request, syncronous.
if(req.route === false){
// 404...
}
// If in the routing schema access was "auth",
// this route requires authentication, so do that...
if(req.route.access === 'auth'){
getAuth(function(error, user){
if(error){ // 401 } else {
req.user = user;
}
}
}
if(req.method === 'POST' || req.method === 'PUT'){
// Async functions.
getRequestData(function(){
parseRequestData(function(){
validateRequestData(function(){
requireControllerAndCallAction();
});
});
});
} else {
requireControllerAndCallAction();
}
}
如您所见，有些函数是异步的（getAuth、getRequestData），有些是同步的（parseRequestData、validateRequestData）。
现在事情是这样的：
请求 1. 附带方法 POST、url '/users' 和数据：
- 全名 = '瑞克'
- 电子邮件：'rick@'
- 密码：'a'
所以我们循环遍历 API 的工作流程：
获取当前路由（控制器：用户，操作：创建） 查看 routes.js 中的第二个数组元素
获取请求数据和回调：解析数据 B. 验证数据
现在让我们想象一下，数据的验证需要 5 秒（这是延迟的，但只是举例），在验证期间，一个新的请求进来了，直到前一个请求完成才处理新的请求，对吧？