Node.js + Express.js 应用的错误处理原则? [英] Error handling principles for Node.js + Express.js applications?

问题描述

似乎在 Node.js+Express.js 与其他框架相比的应用程序.我是否正确理解它的工作原理如下?

It seems like error reporting/handling is done differently in Node.js+Express.js applications compared to other frameworks. Am I correct in understanding that it works as follows?

A) 检测 错误，将它们作为回调函数的参数接收.例如:

A) Detect errors by receiving them as parameters to your callback functions. For example:

doSomethingAndRunCallback(function(err) { 
    if(err) { … }
});

B) 通过调用 next(err) 报告 MIDDLEWARE 中的错误.示例:

B) Report errors in MIDDLEWARE by calling next(err). Example:

handleRequest(req, res, next) {
    // An error occurs…
    next(err);
}

C) 通过抛出错误来报告 ROUTES 中的错误.示例:

C) Report errors in ROUTES by throwing the error. Example:

app.get('/home', function(req, res) {
    // An error occurs
    throw err;
});

D) 通过 app.error() 配置您自己的错误处理程序或使用通用的 Connect 错误处理程序来处理错误.示例:

app.error(function(err, req, res, next) {
    console.error(err);
    res.send('Fail Whale, yo.');
});

这四个原则是否是 Node.js+Express.js 应用程序中所有错误处理/报告的基础?

Are these four principles the basis for all error handling/reporting in Node.js+Express.js applications?

推荐答案

Node.js 中的错误处理通常采用 A) 格式.大多数回调返回一个错误对象作为第一个参数或 null.

Error handling in Node.js is generally of the format A). Most callbacks return an error object as the first argument or null.

Express.js 使用中间件，中间件语法使用 B) 和 E)(如下所述).

Express.js uses middleware and the middleware syntax uses B) and E) (mentioned below).

C) 如果你问我是不好的做法.

C) is bad practice if you ask me.

app.get('/home', function(req, res) {
    // An error occurs
    throw err;
});

您可以轻松地将上面的内容重写为

You can easily rewrite the above as

app.get('/home', function(req, res, next) {
    // An error occurs
    next(err);
});

中间件语法在 get 请求中有效.

Middleware syntax is valid in a get request.

至于 D)

(07:26:37 PM) tjholowaychuk:app.error 在 3.x 中被删除

(07:26:37 PM) tjholowaychuk: app.error is removed in 3.x

TJ 刚刚确认 app.error 已被弃用而支持 E

TJ just confirmed that app.error is deprecated in favor of E

E)

app.use(function(err, req, res, next) {
  // Only handle `next(err)` calls
});

任何长度为 4(4 个参数)的中间件都被视为错误中间件.当调用 next(err) 时，connect 会调用基于错误的中间件.

Any middleware that has a length of 4 (4 arguments) is considered error middleware. When one calls next(err) connect goes and calls error-based middleware.

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