Making API call using swift - swift

Question

I am a TOTAL NOOB when it comes to iOS coding.
Im trying to learn how to make an API call to "http://de-coding-test.s3.amazonaws.com/books.json"
however, since I'm a total noob, all tutorials i find make no sense as to how to do it.
All i want to learn is how I can get the JSON data from the web and input it into a UITableViewCell
I have looked through about 3 dozen tutorials, and nothing makes sense.
Any help is appreciated.

Answer 1

Let's going by step:
1) The framework that you're going to use to make api call is NSURLSession (or some library like Alomofire, etc).
An example to make an api call:
func getBooksData(){
let url = "http://de-coding-test.s3.amazonaws.com/books.json"
(NSURLSession.sharedSession().dataTaskWithURL(NSURL(string: url)!) { (data:NSData?, response:NSURLResponse?, error:NSError?) -> Void in
//Here we're converting the JSON to an NSArray
if let jsonData = (try? NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableLeaves)) as? NSArray{
//Create a local variable to save the data that we receive
var results:[Book] = []
for bookDict in jsonData where bookDict is NSDictionary{
//Create book objects and add to the array of results
let book = Book.objectWithDictionary(bookDict as! NSDictionary)
results.append(book)
}
dispatch_async(dispatch_get_main_queue(), { () -> Void in
//Make a call to the UI on the main queue
self.books = results
self.tblBooks.reloadData()
})
}
}).resume()
}
Book Entity:
class Book{
var title:String
init(title:String){
self.title = title
}
class func objectWithDictionary(dict:NSDictionary)->Book{
var title = ""
if let titleTmp = dict.objectForKey("title") as? String{
title = titleTmp
}
return Book(title: title)
}
}
Note: In practice, you will check error and status code of response, and also you can extract the code of making api call to another class (or service layer).One option, using the pattern of DataMapper, you can create a class Manager by Entities (In this example for book like BookManager) and you can make something like this (You can abstract even more, creating a general api, that receive a url and return an AnyObject from the transformation of the JSON, and from there process inside your manager):
class BookManager{
let sharedInstance:BookManager = BookManager()
private init(){}
func getBookData(success:([Book])->Void,failure:(String)->Void){
let url = "http://de-coding-test.s3.amazonaws.com/books.json"
(NSURLSession.sharedSession().dataTaskWithURL(NSURL(string: url)!) { (data:NSData?, response:NSURLResponse?, error:NSError?) -> Void in
if error != nil{
failure(error!.localizedDescription)
}else{
if let jsonData = (try? NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableLeaves)) as? NSArray{
var results:[Book] = []
for bookDict in jsonData where bookDict is NSDictionary{
let book = Book.objectWithDictionary(bookDict as! NSDictionary)
results.append(book)
}
success(results)
}else{
failure("Error Format")
}
}
}).resume()
}
}