Handling JSON pagination, and adding data to a table view? - swift

Question

I'm getting a JSON response of the format:
{
"current_page":1,
"data":[
{
"id":1,
"title":"Title 1"
},
{
"id":2,
"title":"Title 2"
},
{
"id":3,
"title":"Title 3"
}
]
}
As you can see, data contains a list of objects, in this case, a list of Posts. Here is my Realm/Objectmapper Post class:
import RealmSwift
import ObjectMapper
class Post: Object, Mappable {
let id = RealmOptional<Int>()
#objc dynamic var title: String? = nil
required convenience init?(map: Map) {
self.init()
}
func mapping(map: Map) {
}
}
I created a generic class (I'm not sure it's written right) to handle Pagination responses. I want it to be generic because I have other pagination responses that return Users instead of Posts, among other objects.
Here is my current Pagination class:
import ObjectMapper
class Pagination<T: Mappable>: Mappable {
var data: [T]?
required convenience init?(map: Map) {
self.init()
}
func mapping(map: Map) {
data <- map["data"]
}
}
However, I'm not sure if I've written this class right.
And here is the class where I call the endpoint that sends back the pagination data (I've removed irrelevant code):
var posts = [Post]()
provider.request(.getPosts(page: 1)) { result in
switch result {
case let .success(response):
do {
let json = try JSONSerialization.jsonObject(with: response.data, options: .allowFragments)
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// Not sure what to do here to handle and retrieve the list of Posts
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// Eventually, I need to append the posts to the variable
// self.posts.append(pagination.data)
// Reload the table view's data
self.tableView.reloadData()
} catch {
print(error)
}
case let .failure(error):
print(error)
break
}
}
How do I handle the JSON response correctly in order to get the list of Posts and then append them to the var posts = [Post]() variable? Do I need to make any changes to my Pagination class?

Answer 1

Once you have your json, it is easy to parse it using object mapper:
let pagination = Mapper<Pagination<Post>>().map(JSONObject: json)
It could be further generalized, I have used a direct reference as an example. Your Pagination class can also hold the current page index value.
I think you are also missing the implementation of the mapping(map:) function in your Post class, it should be something like this:
func mapping(map: Map) {
title <- map["title"]
}