为什么将app.get（）放在express.js的正确位置很重要？

我刚刚注意到了一些我没想到的事情。我一直试图“哼一声”一段时间，但没有完全pipe理。这让我疯狂…

采取标准的Expressjs文件。我加了一些东西：

/** * Module dependencies. */ var express = require('express') , routes = require('./routes') , http = require('http') , path = require('path'); var app = express(); app.configure(function(){ app.set('port', process.env.PORT || 3000); app.set('views', __dirname + '/views'); app.set('view engine', 'jade'); app.use(express.favicon()); app.use(express.logger('dev')); app.post( '/call/loginAnon', function(req,res, next){ console.log("IN THE CALL! %j %j %j", req.path, req.body, req.headers ); next(); }); app.use(express.bodyParser()); app.use(express.methodOverride()); app.use(app.router); app.use(express.static(path.join(__dirname, 'public'))); }); app.configure('development', function(){ app.use(express.errorHandler()); }); app.get('/', routes.index); http.createServer(app).listen(app.get('port'), function(){ console.log("Express server listening on port " + app.get('port')); });

我还为bodyParser.js添加了一条debugging线，以便我们知道它何时被调用。请注意，/ call / loginAnon是在 bodyParser 之前定义的。这是结果：

IN THE CALL! "/call/loginAnon" undefined {"host":"localhost:3000","connection":"keep-alive","content-length":"30","origin":"http://localhost:3000","x-requested-with":"XMLHttpRequest","user-agent":"Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1","content-type":"application/json","accept":"application/javascript, application/json","referer":"http://localhost:3000/login","accept-encoding":"gzip,deflate,sdch","accept-language":"en-GB,en-US;q=0.8,en;q=0.6","accept-charset":"ISO-8859-1,utf-8;q=0.7,*;q=0.3","cookie":"sid=s%3ASI%2F9XFcpe2qFdQNrmsL8ihz8.MezqsOBJM%2FWX9BZOJ0za7F1d8UX6sNjmQZBhN3mqFVA"}

Headers IN BODYPARSER.js: /call/loginAnon {"host":"localhost:3000","connection":"keep-alive","content-length":"30","origin":"http://localhost:3000","x-requested-with":"XMLHttpRequest","user-agent":"Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1","content-type":"application/json","accept":"application/javascript, application/json","referer":"http://localhost:3000/login","accept-encoding":"gzip,deflate,sdch","accept-language":"en-GB,en-US;q=0.8,en;q=0.6","accept-charset":"ISO-8859-1,utf-8;q=0.7,*;q=0.3","cookie":"sid=s%3ASI%2F9XFcpe2qFdQNrmsL8ihz8.MezqsOBJM%2FWX9BZOJ0za7F1d8UX6sNjmQZBhN3mqFVA"}

IN THE CALL! "/call/loginAnon" {"login":"sd","password":"sd"} {"host":"localhost:3000","connection":"keep-alive","content-length":"30","origin":"http://localhost:3000","x-requested-with":"XMLHttpRequest","user-agent":"Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1","content-type":"application/json","accept":"application/javascript, application/json","referer":"http://localhost:3000/login","accept-encoding":"gzip,deflate,sdch","accept-language":"en-GB,en-US;q=0.8,en;q=0.6","accept-charset":"ISO-8859-1,utf-8;q=0.7,*;q=0.3","cookie":"sid=s%3ASI%2F9XFcpe2qFdQNrmsL8ihz8.MezqsOBJM%2FWX9BZOJ0za7F1d8UX6sNjmQZBhN3mqFVA"}

所以，我的callback最终被召唤了两次 – 一次在bodyparser被调用之前（所以req.body为null ），一次之后（ req.body实际设置）。

将bodyParser下的呼叫转移到某种程度上有所改善：

仍然叫两次。不过，至less这个时候它已经被要求设置了。

将它移动到app.configure的最后，实际上修复了所有这一切：

这是我一直以来做的事情（以及大多数人永远都会做的事情）。我恰好在configuration之前定义了一个路由，并注意到了怪异。

我相信这是由于我没有正确理解expressJs在定义路线时的工作性质。但是…有人可以解释一下吗？

谢谢，

芝加哥商业交易所。

多次访问path的原因是您在app.router中间件之前定义了处理程序。

原因是中间件将按照定义的顺序使用，每个层都会响应请求或将其发送到下一层。所以解释你的例子：

  // The handler is defined before the router so any request that passed the // previous middleware will also be passed into this middleware // The method (GET or POST or..) or the path is irrelevant at this point app.post( '/call/loginAnon', function(req,res, next){ // Will run every time console.log("IN THE CALL! %j %j %j", req.path, req.body, req.headers ); next(); // It is sent to the next middleware layer }); // Now the bodyParsel will parse the body and give you the req.body variable app.use(express.bodyParser()); app.use(express.methodOverride()); // This handler will now parse the path of the request and redirect it // to the defined handler which is why it is accessed the second time app.use(app.router);

为什么将app.get（）放在express.js的正确位置很重要？

“访问资源权限不足”：使用Mongoose + Express的ACL中间件

让webpack热点更新在我的同构web应用程序中正常工作

如何使用Express.js正确设置单页应用程序的路线？

Express – 将数据传递给所有路线

发送后无法设置标题

为什么expressjs每个OPTIONS响应都发送Set-Cookie头？

cassandra当前与节点js的时间戳

socket.io – 不能得到它的工作，有404的某种投票电话

redirect在ExpressJS中不起作用

Nodejs + expressjs在服务器超时后重播请求