How to write Dictionary to a file?

Question

I have a FileHelper class where I\'ve implemented 3 methods whose job is to write a Dictionary contents to a file. Those methods are:

func storeDictionary(_ dict         


        

Answer 1

First of all filePath?.absoluteString returns the entire – even percent escaped – string including the file:// scheme and the method expects a path without the scheme (filePath?.path - the naming is a bit confusing ;-) ).

I recommend to save a [String:String] dictionary as property list file. It's not necessary to create the file explicitly.

I changed the signatures of the methods slightly in the Swift-3-way. Further there is no need to use any optional type.

func store(dictionary: Dictionary<String, String>, in fileName: String, at directory: String) -> Bool {
    let fileExtension = "plist"
    let directoryURL = create(directory:directory)
    do {
        let data = try PropertyListSerialization.data(fromPropertyList: dictionary, format: .xml, options: 0)
        try data.write(to: directoryURL.appendingPathComponent(fileName).appendingPathExtension(fileExtension))
        return true
    }  catch {
        print(error)
        return false
    }
}

func create(directory: String) -> URL {
    let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
    let directoryURL = documentsDirectory.appendingPathComponent(directory)

    do {
        try FileManager.default.createDirectory(at: directoryURL, withIntermediateDirectories: true, attributes: nil)
    } catch let error as NSError {
        fatalError("Error creating directory: \(error.localizedDescription)")
    }
    return directoryURL
}

PS: Instead of returning a Bool you could make the store method can throw and handle the error in the calling method:

func store(dictionary: Dictionary<String, String>, in fileName: String, at directory: String) throws {
    let fileExtension = "plist"
    let directoryURL = create(directory:directory)

    let data = try PropertyListSerialization.data(fromPropertyList: dictionary, format: .xml, options: 0)
    try data.write(to: directoryURL.appendingPathComponent(fileName).appendingPathExtension(fileExtension))
}