如何在ExpressRouter.route和控制器模式中触发next()

Question

在请求到达我的一个api路由后，我似乎不知道如何实现"next(("。我想在一切完成后进行日志记录，而不是在我的api路由之前。我已经在我的路由上实现了控制器模式。我现在只能记录错误，但我想记录所有请求：

//------ api/index.js
import routes from './routes/index.route';
app.use('/api', routes);

// ??? HOW TO HANDLE next() called in "/api routes"
// only handles incoming requests not found in "/api routes"
app.use((req, res, next) => {
// logic here...
next(error);
});

// global error handler
app.use((error, req, res, next) => {
// logging logic here...
});

//------ routes/index.route.js
import express from 'express';
import userRoutes from './user.route';
import bookRoutes from './book.route';
const router = express.Router();
router.use('/user', userRoutes);
router.use('/book', bookRoutes);

//------ routes/book.route.js
import express from 'express';
import bookCtrl from './../controllers/book.controller';
const router = express.Router();
router.route('/:bookId').get(bookCtrl.getBook);


//------ controllers/book.controller.js
export const getBook = async (req, res, next) => {
const book = // get book logic here;
return res.status(httpStatus.OK).json(book);
// HOW DO I TRIGGER next()?  
// I tried this approach as well: 
// res.status(httpStatus.OK).json(book);
// next();
//however, it would say, "Error: Can't set headers after they are sent."
}

非常感谢。

Answer 1

我找到了一种触发next的方法，即不立即发送响应，而是将其分配给res.locals并调用next。以下是基于我上面代码的更改：

//------ api/index.js
// handle next() event coming from "/api routes"
// and also handles incoming requests not found in "/api routes"
app.use((req, res, next) => {
if (res.locals.status) {
const { status, responseData } = res.locals;
res.status(status).json(responseData);
// logging logic here...
} else {
// error logic here...
// forward this error into the global error handler
next(error);
}
});

// controllers/book.controller.js
export const getBook = async (req, res, next) => {
// get book logic here..
const book = // get book logic here;
res.locals = {
status: httpStatus.OK,
responseData: {
book,
},
};
next();
}

感谢@destoryer的res.json提示！：(

Answer 2

只需更换

return res.status(httpStatus.OK).json(book);
// HOW DO I TRIGGER next()? 

带有

res.status(httpStatus.OK).json(book);
next();

它会起作用的。