URLSession basics in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is URLSession used for in iOS development?

URLSession is used to make network requests, like downloading data from the internet or sending data to a server.

beginner

What method of URLSession is commonly used to start a simple data task?

The dataTask(with:completionHandler:) method is used to start a task that fetches data from a URL.

beginner

Why do we call resume() on a URLSessionDataTask?

Calling resume() starts the network request. Without it, the task stays suspended and does nothing.

intermediate

What parameters does the completion handler of a URLSession data task provide?

It provides Data? (the response data), URLResponse? (info about the response), and Error? (any error that happened).

intermediate

How can you handle errors when using URLSession?

Check if the Error? parameter in the completion handler is not nil, and handle it by showing a message or retrying.

Which method starts a URLSession data task?

A launch()

B start()

C resume()

D begin()

You must call resume() on the data task to start it.

What type of object does URLSession's dataTask(with:) method return?

A URLSessionDataTask

B URLRequest

C URLResponse

D Data

dataTask(with:) returns a URLSessionDataTask object.

Which parameter in the completion handler contains the downloaded data?

A URLResponse

B Data

C Error

D URLRequest

The Data? parameter contains the downloaded data.

What happens if you forget to call resume() on a URLSessionDataTask?

A The task completes instantly

B The task runs automatically

C The app crashes

D The task never starts

Without resume(), the task stays suspended and does not start.

Which class is responsible for managing network requests in iOS?

A URLSession

B UIViewController

C UIApplication

D URLRequest

URLSession manages network requests like downloading or uploading data.

Explain how to create and start a simple URLSession data task to fetch data from a URL.

Think about the steps from making the request to getting the response.

Describe the role of the completion handler in a URLSession data task.

What do you do after the network call finishes?