Decode PropertyList using Swift 4 Codable PropertyListDecoder()

问题:

Im trying to decode a plist using PropertyListDecoder() but when I get to the trying to access the keys, I get an error that says it's in the wrong format. I'm at a loss on what I'm doing wrong. Im under the assumption I can decode a Plist file the same way I can decode a JSON file right? I don't know, I'm still new to this.

//struct for PLists struct AccessControl: Decodable {     enum AccessControlKeys: String, CodingKey {          case api      }      enum KeySecretKeys: String, CodingKey {         case apiKey = "KEY"         case apiSecret = "SECRET"     }      var KEYS: [KeySecrets] //custom decoder     init(from decoder: Decoder) throws {         let accessContainer = try decoder.container(keyedBy: AccessControlKeys.self)         let nestedContainer = try accessContainer.nestedContainer(keyedBy: KeySecretKeys.self, forKey: .api)         self.KEYS = try nestedContainer([KeySecrets].self, forKey: .apiKey)         self.KEYS = try nestedContainer.decode([KeySecrets].self, forKey: .apiSecret)     } }  struct KeySecrets: Decodable {     var apiKey: String     var apiSecret: String }    func provideAccessKeys(for api: apis = .api, mode: modes = .dev) -> keysForApi? {     switch api {     case .api:         print("Api")     }     switch mode {     case .dev:         print("mode - developers")     case .test:         print("mode - test")     case .prod:         print("mode - production")     } } 

This was my first approach at it, but it would throw an error saying

'The data couldn't be read because it was the wrong format'

if let fileURL = Bundle.main.url(forResource: "Accesscontrol",   withExtension: "plist") {     do {         let data = try Data.init(contentsOf: fileURL, options: .mappedIfSafe)         let decoder = PropertyListDecoder()         let result = try decoder.decode(AccessControl.self, from: data)      } catch {         print(error.localizedDescription)     } } 

Second approach, kinda just abandoned Codable all together, still couldn't pull out the values

guard let fileUrl = Bundle.main.url(forResource: "Accesscontrol", withExtension: "plist") else {return} let key: String let secret: String do {     let data = try Data.init(contentsOf: fileUrl, options: .mappedIfSafe)     let plist = try! PropertyListSerialization.propertyList(from:data, options: [], format: nil) as! [Any]   print(plist)    let dictionary = plist[api.rawValue]  } catch {     print(error.localizedDescription) } 

The plist file is structured like

<plist version="1.0"> <dict>     <key>A_GROUP_OF_KEYS</key>     <array>         <dict>             <key>KEY1</key>             <string>KEY1_STRING</string>             <key>SECRET1_KEY</key>             <string>SECRET1_STRING</string>         </dict>         <dict>         <key>KEY2</key>         <string>KEY2_STRING</string>         <key>SECRET2_KEY</key>         <string>SECRET2_VALUE</string>         </dict>         <dict>         <key>KEY</key>         <string>KEY_STRING</string>         <key>SECRET_KEY</key>         <string>SECRET_VALUE</string>         </dict>     </array> <key>ANOTHER_GROUP_OF_KEYS</key>     <array>         <dict>             <key>KEY1</key>             <string>KEY1_STRING</string>             <key>SECRET1_KEY</key>             <string>SECRET1_STRING</string>         </dict>         <dict>         <key>KEY2</key>         <string>KEY2_STRING</string>         <key>SECRET2_KEY</key>         <string>SECRET2_VALUE</string>         </dict>         <dict>         <key>KEY</key>         <string>KEY_STRING</string>         <key>SECRET_KEY</key>         <string>SECRET_VALUE</string>         </dict>     </array> </dict> </plist> 

Any advice?

回答1:

Your plist file was badly formatted and hence undecodable. You don't name every key with a different key name like KEY1, KEY2, KEY3, etc. You use one name for the key key and put the actual name in the value field. The same goes for secret.

Here's a better plist file:

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict>     <key>A_GROUP_OF_KEYS</key>     <array>         <dict>             <key>key</key>             <string>KEY1_STRING</string>             <key>secret</key>             <string>SECRET1_STRING</string>         </dict>         <dict>             <key>key</key>             <string>KEY2_STRING</string>             <key>secret</key>             <string>SECRET2_VALUE</string>         </dict>         <dict>             <key>key</key>             <string>KEY3_STRING</string>             <key>secret</key>             <string>SECRET3_VALUE</string>         </dict>     </array>     <key>ANOTHER_GROUP_OF_KEYS</key>     <array>         <dict>             <key>key</key>             <string>KEY1_STRING</string>             <key>secret</key>             <string>SECRET1_STRING</string>         </dict>         <dict>             <key>key</key>             <string>KEY2_STRING</string>             <key>secret</key>             <string>SECRET2_VALUE</string>         </dict>         <dict>             <key>key</key>             <string>KEY3_STRING</string>             <key>secret</key>             <string>SECRET3_VALUE</string>         </dict>     </array> </dict> </plist> 

Decoding this is dead simple:

struct AccessControl: Decodable {     struct Key: Decodable {         var key: String         var secret: String     }      var keyGroup1: [Key]     var keyGroup2: [Key]      enum CodingKeys: String, CodingKey {         case keyGroup1 = "A_GROUP_OF_KEYS"         case keyGroup2 = "ANOTHER_GROUP_OF_KEYS"     } } 

文章来源: Decode PropertyList using Swift 4 Codable PropertyListDecoder()