Implement writing and reading to Property List (.plist) in Swift

Data writing and data reading to Property List (.plist file) is performed using a model compliant with PropertyListEncoder (Decoder) and Codable.

Premise

Swift: 5.0

Implementation

Preparing the model

Create a model of the data you want to save in the Property List in a form that conforms to Codable. This time, as an example, let's use Book, which has a title and author name as elements, as a model.

Book.swift

struct Book: Codable {
    var title: String
    var writerName: String
}

Writing data

File operations are performed using FileManager. You can write to the Property List by encoding the model prepared earlier using PropertyListEncoder.

BookManager.swift

class BookManager {
    //URL Path of the Property List to be handled
    static private var plistURL: URL {
        let documents = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        return documents.appendingPathComponent("book.plist")
    }

    static func write(book: Book) {
        let encoder = PropertyListEncoder()
        //Encode the data you want to save
        guard let data = try? encoder.encode(book) else { return }
        //Overwrite if the Property List already exists. If not, create a new one
        if FileManager.default.fileExists(atPath: plistURL.path) {
            try? data.write(to: plistURL)
        } else {
            FileManager.default.createFile(atPath: plistURL.path, contents: data, attributes: nil)
        }
    }
}

Data reading

Similar to writing data, file operations are performed using FileManager. The data read from the Property List is decoded into the Book model using PropertyListDecoder.

BookManager.swift

class BookManager {
    //abridgement//

    static func load() -> Book {
        let decoder = PropertyListDecoder()
        //Read data from the destination Property List and decode
        guard let data = try? Data.init(contentsOf: plistURL), 
              let book = try? decoder.decode(Book.self, from: data) else { 
              return Book(title: "", writerName: "")
        }
        return book
    }
}

At the end

By using Codable andPropertyListEncoder (Decoder), I was able to easily implement data manipulation with Property List (.plist).

reference

• Using Swift Codable With Property List
• Reading and writing Property List files with Codable in Swift