API 请求没有给出响应

Posted 2023-02-24

【中文标题】API 请求没有给出响应

【英文标题】：API request isn't giving a response

【发布时间】：2020-02-24 02:39:17

【问题描述】：

我正在尝试使用 (https://collegescorecard.ed.gov/data/documentation/) 在我的 ios 应用程序中填充表格，但没有任何数据显示。我已经尝试了很多次我的 api 密钥和 url，所以我不认为它是那样的。 json文件的结构

开发类学校

名称字符串 IPEDS 中报告的机构名称 (INSTNM)。

import UIKit
import Alamofire

class ViewController: UIViewController 
    let URLStr = "https://api.data.gov/ed/collegescorecard/v1/schools?fields=school.name"

    var resultArray = [Users]()
    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var searchBar: UISearchBar!
     var searchCollege = [String]()

override func viewDidLoad() 
         super.viewDidLoad()
         tableView.dataSource = self
         tableView.delegate = self
         callAPI()


            
    override func didReceiveMemoryWarning() 
           super.didReceiveMemoryWarning()
       

func callAPI() 
        let key = "key redacted"
        //let url = URL(string:"\(URLStr)?api_key=\(key)")
        let url = URL(string:"\(URLStr)&api_key=\(key)")
        print(url)
        Alamofire.request(url!, method: .get, parameters: nil, headers:[:]).responseJSON (response) in
            if let responseObj = response.value as? [[String: Any]]
                self.resultArray = self.parseJSON(userData: responseObj)
                print("response here", response)
                self.tableView.reloadData()
                
        


func parseJSON(userData: [[String:Any]])-> [Users] 
    var userArr = [Users]()
    for obj in userData 
        do  let data = try JSONSerialization.data(withJSONObject: obj, options: .prettyPrinted)
            let decodedData = try JSONDecoder().decode(Users.self, from: data)
            userArr.append(decodedData)
            

    catch 

        
    
        return userArr
    

userModal.swift

mport Foundation
struct Users: Codable 
    let userSchool_name: String?

enum CodingKeys: String, CodingKey 
    case userSchool_name = "school.name"

我试图打印出响应和不同的对象，但没有打印出来。我在下面有一个函数可以在应用程序中显示它，但我认为这不是问题。

json 输出

SUCCESS: 
    metadata =     
        page = 0;
        "per_page" = 20;
        total = 7112;
    ;
    results =     (
                
            "school.name" = "West Michigan College of Barbering and Beauty";
        ,
                
            "school.name" = "Georgia College & State University";
        ,
                
            "school.name" = "Georgia Southern University";
        ,
                
            "school.name" = "Clayton  State University";
        ,
                
            "school.name" = "Andrew College";
        ,
                
            "school.name" = "Columbus Technical College";
        ,
                
            "school.name" = "Georgia Northwestern Technical College";
        ,
                
            "school.name" = "Atlanta Metropolitan State College";
        ,
                
            "school.name" = "Clark Atlanta University";
        ,
                
            "school.name" = "Augustana College";
        ,
                
            "school.name" = "Miami Ad School at Portfolio Center";
        ,
                
            "school.name" = "Tricoci University of Beauty Culture-Urbana";
        ,
                
            "school.name" = "University of Hawaii at Manoa";
        ,
                
            "school.name" = "Aveda Institute-Twin Falls";
        ,
                
            "school.name" = "Cameo Beauty Academy";
        ,
                
            "school.name" = "Truett McConnell University";
        ,
                
            "school.name" = "Cannella School of Hair Design-Chicago";
        ,
                
            "school.name" = "Valdosta State University";
        ,
                
            "school.name" = "American Academy of Art";
        ,
                
            "school.name" = "City Colleges of Chicago-Kennedy-King College";
        
    );

【问题讨论】：

是否打印url？

您是否尝试在条件if let responseObj = response.value as? [[String: Any]]之前打印响应

@Rob 的 url 确实打印出来了，但是谢谢

@jenna 好的，parseJSON 成功了吗？

@Joshua 它确实在 if let responseObj = response.value as? [[String: Any]] 之前打印，所以我认为它没有成功地执行 parseJSON @Rob

【参考方案1】：

首先删除parseJSON，把JSON转成数组，再转回JSON，再转成带有JSONDecoder的struct是没有意义的

罢工>

func parseJSON(userData: [[String:Any]])-> [Users] 
var userArr = [Users]()
for obj in userData 
    do  let data = try JSONSerialization.data(withJSONObject: obj, options: .prettyPrinted)
        let decodedData = try JSONDecoder().decode(Users.self, from: data)
        userArr.append(decodedData)
        

catch 

    

    return userArr

  

然后你必须为根对象添加一个结构

struct Root: Codable 
    let results : [Users]


struct Users: Codable 
    let userSchool_name: String?

     private enum CodingKeys: String, CodingKey 
        case userSchool_name = "school.name"
     

并将 Alamofire 部分替换为

   Alamofire.request(url!).responseData  response in
        switch response.result 
            case .success(let data):
                do 
                    self.resultArray = try JSONDecoder().decode(Root.self, from: data).results
                    self.tableView.reloadData()
                 catch 
                    print(error)
            
            case .failure(let error):
                print(error)
        
    

它接收Data而不是解码的数组并处理所有错误。

【讨论】：

感谢您的输入，但我收到此错误，typeMismatch(Swift.Array, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Array 但是而是找到了字典。”，基础错误：无））

谢谢-> 但是它给出的值是 nil，print(self.resultArray) 给出 Application.Users(userSchool_name: nil)，但是对于正确数量的学校

CodingKeys 枚举必须在 Users 结构内，您可以声明 userSchool_name 非可选和 lowerCamelCased。