在Express JS中使用可选的中间件

Question

我想知道在Express路由中使用可选的中间件看起来像这样：

router.post("/findAvailableAgents", middleware1 || middleware2, (req, res))

Answer 1

You could use another middleware which decides whether to choose middleware1 or middleware2

const decideMiddleware = (req, res, next) => {
    if(condition) {
        return middleware1(req, res,next)
    } else {
        return middleware2(req, res,next)
    }
}

And use it in your code

router.post("/findAvailableAgents", decideMiddleware, (req, res))

Answer 2

There is two ways of achieve optional middleware behaviour:

1) Create another middleware, that checks condition and then passes all the parameters into the desired middleware. Example:

const middlewareStrategy = (req,res,next) => {
    if(req.body.token1){
        return middleware1(req,res,next);
    }
    return middleware2(req,res,next);
};

router.post("/findAvailableAgents", middlewareStrategy, handler);

2) Make middleware logic execution in a condition-driven manner. Example:

const middleware1 = (req,res,next) => {
    if(req.body.token){
        // execute some logic, then
        return next();
    }
    // skip this middleware
    next();
};

router.post("/findAvailableAgents", middleware1, middleware2, handler);

Answer 3

Now you can add multiple middleware using a below peice of code

 app.get('/',[middleware.requireAuthentication,middleware.logger], function(req, res){ res.send('Hello!'); });