从NodeJS/ExpressJS的中间件中调用中间件 [英] Calling a middleware from within a middleware in NodeJS/ExpressJS
本文介绍了从NodeJS/ExpressJS的中间件中调用中间件的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我已经创建了具有一些逻辑的标准中间件,并且根据逻辑,我需要调用一些第三方中间件.
I have created some standard middleware with some logic, and depending on the logic I need to call some 3rd party middleware.
使用app.use()添加中间件,这是我添加自定义中间件的地方.
Middleware is added using app.use(), which is where I add my custom middleware.
在我的中间件中,我不再有权访问app.use(),该如何调用中间件?
Once in my middleware I no longer have access to app.use(), how do I call the middleware?
这是一些代码:
有什么想法吗?
const customerData = (req, res, next) => {
try {
console.log('Started');
if (process.env.STORE_CUSTOMER_DATA === 'true') {
// Here is some custom middleware that doesn't belong to me
//
// Returns a function (I confirmed it) ready to be called with res,req, next
//
let externalMiddlware = logger({
custom:true
});
// Do I return it ? Call it ? Trying everything and nothing seems to work
externalMiddlware(req,res,next); // ???
} else {
// DO not call external middleware, will break out of if and then call next()
}
console.log('Finished');
next();
} catch (err) {
next(err);
}
};
module.exports = customerData;
推荐答案
我认为这应该可行,但是如果将回调委派给该其他externalMiddlware,则不应在customerData中调用next()使用此第三种中间件
I think this should work but if you delegate the callback to this other externalMiddlware you should not call next() in customerData use this 3rd middleware
所以您尝试过
const customerData = (req, res, next) => {
try {
console.log('Started');
if (process.env.STORE_CUSTOMER_DATA === 'true') {
let externalMiddlware = logger({
custom:true
});
return externalMiddlware(req,res,next);
} else {
return next(); // <= next moved
}
} catch (err) {
next(err);
}
};
module.exports = customerData;
这篇关于从NodeJS/ExpressJS的中间件中调用中间件的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文