如何处理nodejs表示的响应和下一步
[英]how to handle response and next in nodejs express
问题描述
I was wondering how should I be dealing with response and next in express. 
我想知道我应该如何处理响应和接下来的快递。
My understanding is that when I say res.send(...) -> returns a response 我的理解是，当我说res.send（...） - >返回一个响应
If I want to throw an error, I say next(new Error('whatever')) -> auto sets the http status code using express errorhandler. 如果我想抛出错误，我说下一个（新错误（'不管'）） - >使用快速错误处理程序自动设置http状态代码。
I am able to do either of those but not but, looks like I am messing up. 我可以做其中任何一个但不是，但看起来我搞砸了。
Can anyone give an example? 谁能举个例子？
I tried, 我试过了，
somefunc(err, req, res, next) {
if(err) {
res.send(500, 'some error');
return next(err);
}
}
return [somefunc, express.errorHandler()];
thanks. 谢谢。
2 个解决方案
解决方案1
1 2014-03-20 01:29:03
You can register some middleware to handle errors: 您可以注册一些中间件来处理错误：
app.use(function(err, req, res, next){
console.error(err.stack);
res.send(500, 'Something broke!');
});
You can also simply send a 500 with your response if you encounter an error in your logic 如果在逻辑中遇到错误，您也可以简单地发送500响应
function loginUser(req, res, next) {
try {
var valid;
//code to check user
if (valid) {
next();
} else {
res.send(401, 'not authorized');
}
} catch (err) {
res.send(500, 'Oopsy');
}
}
app.get('/some/route',loginUser, function(req, res) {
// ...
});
解决方案2
1 2014-03-20 17:40:18
Just skip return next(); 只需跳过return next(); part. 部分。 Use return res.send(500,'some error'); 使用return res.send(500,'some error'); Calling next causes next middleware to be called which IMO is not what you want in this case. 调用next会导致调用next一个中间件，在这种情况下，IMO不是您想要的。 I wrote more about it here . 我在这里写了更多关于它的内容
Here is minimal example of express stack: 这是快速堆栈的最小示例：
express = require('express');
app = express();
app.configure(function() {
app.use(express.bodyParser());
app.use(express.cookieParser());
app.use(app.router());
app.use(express.static(__dirname + '/public'));
});
app.get('/', function(req, res) {
if (some error)
res.send(500, 'Some error');
else
res.send('<body>Hello</body>');
});
app.listen(3000); // listen on port 3000
The get request will be called by router middleware. get请求将由router中间件调用。 Middlewares are parsed as chain. 中间件被解析为链。 You can use custom middleware in this chain, for example: 您可以在此链中使用自定义中间件，例如：
app.configure(function() {
app.use(express.bodyParser());
app.use(express.cookieParser());
app.use(function(req, res, next){
if (some condition)
res.send(500, 'No way'); // this will break the request chain
else
next(); // this will continue processing and will call app.router middleware
});
app.use(app.router());
app.use(express.static(__dirname + '/public'));
});
app.router middleware is responsible for calling appropriate method based on requested URL (like app.get('/') ). app.router中间件负责根据请求的URL调用适当的方法（如app.get('/') ）。 If it fails to find one, it calls next() to pass control to express.static middleware which tries to find static file in /public/ folder. 如果找不到，则调用next()将控制权传递给express.static中间件，该中间件试图在/public/文件夹中查找静态文件。
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