How to make a http request in swift? (ERROR: on json)

Question

I have an error running my code. I need to represent whole information of my data requested from the URL. But this breaks when I run. I think the code is well done, but I don't know why this breaks when I run the app. Probably have some error when threats the JSON.

This error:

Thread 3: Fatal error: Unexpectedly found nil while unwrapping an Optional value

import Foundation

public class UnidadeCurricularManager{
private var ucs = [UnidadeCurricular]();


init(){        

    //URL

    let url = URL(string: "http://209.97.133.56/api/ucs")!
    let token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6IjQ2Yjg2ZDNlZDI2Y2IwOGU2NDFhZTI3NjNmMWI0ZDEwODAwZWI0M2U4YjM5MThiMTQ0YmU5YWFjMzBhNGU1ZDdhMTI4ZjA1MDI2NGNkYWZhIn0.eyJhdWQiOiIyIiwianRpIjoiNDZiODZkM2VkMjZjYjA4ZTY0MWFlMjc2M2YxYjRkMTA4MDBlYjQzZThiMzkxOGIxNDRiZTlhYWMzMGE0ZTVkN2ExMjhmMDUwMjY0Y2RhZmEiLCJpYXQiOjE1NTgzNDQ1MDIsIm5iZiI6MTU1ODM0NDUwMiwiZXhwIjoxNTg5OTY2OTAyLCJzdWIiOiIzIiwic2NvcGVzIjpbXX0.LSsn172WUQqEzUf3wzq4lxgBL8pbKGqjJCpn0iEFPFQY6DhZCtcm4jHkqTC0FFMYrAA1n87LfdBeSvcdgWFsndD6MoKHFkZViqZXlUHDeyMmT-bVs2IrNSE9kGuaRQhz1rtys2KFbB2y4lq5w2BPhokPYvLc0nTwZ7oPTZKQlJkUi80PKDMP3LMUQpilc2cSE8FGe-d1UtMYUeseivwHcNee4knjfOUIsGl7_pV4knU6DYTWL8IMXfb3GjbBTagFRWfbjeqMMvtFVdZGfTxdeVoMqSgEQlA0W20GyJ3Ox4WuZAaODk4b7Q4cudR8vmPTSjvVU-IqB6_9wvtE3HUMEwiGazQRcmFtVqBYFPVIBHFWNBsWI2AbMxR_KSA6URzF-6qydj53yRqO41E88KQiWbHy29mb8BCoNvjR4gN9F97rE9j9Xpt-EsHK6QEqBOeoJixu8srDrgmYul4nWroRU6dQsFZjfZS4Vnm1LFF-ykOo0YVY08oRcV3LQTb8TsnS3RuQzlMifEhDajBPTsVyCyW9OkkTsi3N96E1VeRhyT0S08InczXeRV_K5BMdt7tvVAEMPoR4GCcHAR5e7924WVsbl9KmJ4ituf_FdCfBKdvcmErURIlCfZRELLC_8kNaT-04CG3Vj9_LrUb6eOcJrutawh60V_ITojWAxyF2LnQ"
    var request = URLRequest(url: url)
    request.addValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
    request.addValue("application/json", forHTTPHeaderField: "Content-Type")
    request.addValue("application/json", forHTTPHeaderField: "Accept")
    request.httpMethod = "GET"


    URLSession.shared.dataTask(with: request) { (data, response , error) in
        guard let data = data else {
            return
        }
        do {
            if let jsonDictionary = try JSONSerialization.jsonObject(with: data, options : .allowFragments) as? Dictionary<String,Any>
            {
                if let dataArray = jsonDictionary["data"] as? [[String:Any]] {
                    for data in dataArray {

                        let ucIdMapSiges = data["unidadeCurricularIdMapSiges"] as! Int
                        let ucNome = data["unidadeCurricularNome"] as! String
                        let ucSigla = data["unidadeCurricularAbreviatura"] as! String
                        let anoCurricularIdMapSiges = data["anoCurricularIdMapSiges"] as! Int
                        let periodoNome = data["unidadeCurricularAbreviatura"] as! String
                        let codigoEstudante = data["numeroEstudante"] as! String
                        let ects = data["numero_creditos"] as! Int


                        var uc = UnidadeCurricular (ucName: ucNome, ucSigla: ucSigla, ucIdMapSiges: ucIdMapSiges, anoCurricularIdMapSiges: anoCurricularIdMapSiges, periodoNome: periodoNome, codigoEstudante: codigoEstudante, ects: ects)

                        self.ucs.append(uc);
                    }
                }

            } else {
                print("bad json")
            }
        } catch let error as NSError {
            print(error)
        }

        }.resume()

}

func getUcs() -> Dictionary<String, [UnidadeCurricular]> {
    var listaOfUcs = [String : [UnidadeCurricular]]()

    for u in ucs{
        if listaOfUcs[String(u.anoCurricularIdMapSiges)] != nil {
            listaOfUcs[String(u.anoCurricularIdMapSiges)]!.append(u);
        } else {
            var ucName = [UnidadeCurricular]();
            ucName.append(u);
            listaOfUcs[String(u.anoCurricularIdMapSiges)] = ucName;
        }
    }
    return listaOfUcs;
}
}

Please, add JSON response with a question? – Bhavin Bhadani May 20 '19 at 11:17 — Bhavin Bhadani, May 20 '19 at 11:17

Shehata Gamal · Answer 1 · 2019-05-20T11:39:51.140

You cast

let codigoEstudante = data["numeroEstudante"] as! String

but it should be

let codigoEstudante = data["numeroEstudante"] as! Int

A better approach

do {
    let res = try JSONDecoder().decode(Root.self, from: data)
    print(res.data)

} catch  {
    print(error)
}

struct Root : Codable {
    let data:[Model]
}

struct Model : Codable {
    let unidadeCurricularIdMapSiges,anoCurricularIdMapSiges,numeroEstudante,numero_creditos:Int
    let unidadeCurricularNome,unidadeCurricularAbreviatura:String

}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        let ff = UnidadeCurricularManager()

        ff.getData { (res) in
            print(res)
            // refresh the table here
        }

    }
}


public class UnidadeCurricularManager{

    func getData(completion:@escaping ([String:[Model]]) -> ()) {

        let url = URL(string: "http://209.97.133.56/api/ucs")!
        let token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6IjQ2Yjg2ZDNlZDI2Y2IwOGU2NDFhZTI3NjNmMWI0ZDEwODAwZWI0M2U4YjM5MThiMTQ0YmU5YWFjMzBhNGU1ZDdhMTI4ZjA1MDI2NGNkYWZhIn0.eyJhdWQiOiIyIiwianRpIjoiNDZiODZkM2VkMjZjYjA4ZTY0MWFlMjc2M2YxYjRkMTA4MDBlYjQzZThiMzkxOGIxNDRiZTlhYWMzMGE0ZTVkN2ExMjhmMDUwMjY0Y2RhZmEiLCJpYXQiOjE1NTgzNDQ1MDIsIm5iZiI6MTU1ODM0NDUwMiwiZXhwIjoxNTg5OTY2OTAyLCJzdWIiOiIzIiwic2NvcGVzIjpbXX0.LSsn172WUQqEzUf3wzq4lxgBL8pbKGqjJCpn0iEFPFQY6DhZCtcm4jHkqTC0FFMYrAA1n87LfdBeSvcdgWFsndD6MoKHFkZViqZXlUHDeyMmT-bVs2IrNSE9kGuaRQhz1rtys2KFbB2y4lq5w2BPhokPYvLc0nTwZ7oPTZKQlJkUi80PKDMP3LMUQpilc2cSE8FGe-d1UtMYUeseivwHcNee4knjfOUIsGl7_pV4knU6DYTWL8IMXfb3GjbBTagFRWfbjeqMMvtFVdZGfTxdeVoMqSgEQlA0W20GyJ3Ox4WuZAaODk4b7Q4cudR8vmPTSjvVU-IqB6_9wvtE3HUMEwiGazQRcmFtVqBYFPVIBHFWNBsWI2AbMxR_KSA6URzF-6qydj53yRqO41E88KQiWbHy29mb8BCoNvjR4gN9F97rE9j9Xpt-EsHK6QEqBOeoJixu8srDrgmYul4nWroRU6dQsFZjfZS4Vnm1LFF-ykOo0YVY08oRcV3LQTb8TsnS3RuQzlMifEhDajBPTsVyCyW9OkkTsi3N96E1VeRhyT0S08InczXeRV_K5BMdt7tvVAEMPoR4GCcHAR5e7924WVsbl9KmJ4ituf_FdCfBKdvcmErURIlCfZRELLC_8kNaT-04CG3Vj9_LrUb6eOcJrutawh60V_ITojWAxyF2LnQ"
        var request = URLRequest(url: url)
        request.addValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("application/json", forHTTPHeaderField: "Accept")
        request.httpMethod = "GET"


        URLSession.shared.dataTask(with: request) { (data, response , error) in
            guard let data = data else {
                return
            }

         //   print(String(data:data,encoding: .utf8))

            do {
                let res = try JSONDecoder().decode(Root.self, from: data)
                let dic = Dictionary(grouping: res.data, by: { String($0.anoCurricularIdMapSiges) })
                completion(dic)

            } catch let error as NSError {
                print(error)
            }

            }.resume()

       }

}

struct Root : Codable {
    let data:[Model]
}

struct Model : Codable {
    let unidadeCurricularIdMapSiges,anoCurricularIdMapSiges,numeroEstudante,numero_creditos:Int
    let unidadeCurricularNome,unidadeCurricularAbreviatura:String

}

I got this error on my tabview function: Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value — João, May 20 '19 at 11:29
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return ucs[String(section+1)]!.count + 1; } — João, May 20 '19 at 11:29
ok now I got the data on terminal.. but when I click in the button to get the view it does the same error — João, May 20 '19 at 11:40
the info appears in the terminal.. but when I click in 'show ucs' it breaks — João, May 20 '19 at 11:40
you have to use a completion to refresh as in answer , the call to api is asynchronous — Shehata Gamal, May 20 '19 at 11:47

How to make a http request in swift? (ERROR: on json)

1 Answers1