Readings: Express REST API
Review, Research, and Discussion
- Name 3 real world use cases where you’d want to change the request with custom middleware ?
- when you want to manipulate the request (like:add current server time to the request)
- Add query params
- Handling error
- True or false: The route handler is middleware?
- false, They are not middleware functions by definition
- In what ways can a middleware function end the process and send data to the browser?
next(" ");when face somthing bad , will end .next();when it finished the process .
- At what point in the request lifecycle can you “inject” middleware?
- after the request
- What can cause express to error with “Request headers sent twice, cannot start a second response”
- If you pass anything to the next() function (except the string ‘route’), Express regards the current request as being an error and will skip any remaining non-error handling routing and middleware functions.
- When a POST request is sent to /api/route1 it will run every line in the callback. A Can’t set headers after they are sent error message will be thrown because res.json() is called twice, meaning two responses are sent.
ES6 Classes 📁
Using Express Routing 📁
Express Routing 📁
What can a middleware function do? 📁
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Middleware functions can perform the following tasks:
- Execute any code.
- Make changes to the request and the response objects.
- End the request-response cycle.
- Call the next middleware in the stack.
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