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How to check if a file exists in the Documents directory in Swift?

Posted by: admin November 18, 2017 Leave a comment

Questions:

How to check if a file exists in the Documents directory in Swift?

I am using [ .writeFilePath ] method to save an image into the Documents directory and I want to load it every time the app is launched. But I have a default image if there is no saved image.

But I just cant get my head around how to use the [ func fileExistsAtPath(_:) ] function. Could someone give an example of using the function with a path argument passed into it.

I believe I don’t need to paste any code in there as this is a generic question. Any help will be much appreciated.

Cheers

Answers:

Swift 2.0 version, need to use URLByAppendingPathComponent

    let path = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
    let url = NSURL(fileURLWithPath: path)
    let filePath = url.URLByAppendingPathComponent("nameOfFileHere").path!
    let fileManager = NSFileManager.defaultManager()
    if fileManager.fileExistsAtPath(filePath) {
        print("FILE AVAILABLE")
    } else {
        print("FILE NOT AVAILABLE")
    }

Swift 3.0 version

    let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
    let url = URL(fileURLWithPath: path)

    let filePath = url.appendingPathComponent("nameOfFileHere").path
    let fileManager = FileManager.default
    if fileManager.fileExists(atPath: filePath) {
        print("FILE AVAILABLE")
    } else {
        print("FILE NOT AVAILABLE")
    }

Questions:
Answers:

Check the below code:

Swift 1.2

let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String

let getImagePath = paths.stringByAppendingPathComponent("SavedFile.jpg")

let checkValidation = NSFileManager.defaultManager()

if (checkValidation.fileExistsAtPath(getImagePath))
{
    println("FILE AVAILABLE");
}
else
{
    println("FILE NOT AVAILABLE");
}

Swift 2.0

let paths = NSURL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0])
let getImagePath = paths.URLByAppendingPathComponent("SavedFile.jpg")

let checkValidation = NSFileManager.defaultManager()

if (checkValidation.fileExistsAtPath("\(getImagePath)"))
{
    print("FILE AVAILABLE");
}
else
{
    print("FILE NOT AVAILABLE");
}

Questions:
Answers:

Nowadays (2016) Apple recommends more and more to use the URL related API of NSURL, NSFileManager etc.

To get the documents directory in iOS and Swift 2 use

let documentDirectoryURL = try! NSFileManager.defaultManager().URLForDirectory(.DocumentDirectory, 
                                 inDomain: .UserDomainMask, 
                        appropriateForURL: nil, 
                                   create: true)

The try! is safe in this case because this standard directory is guaranteed to exist.

Then append the appropriate path component for example an sqlite file

let databaseURL = documentDirectoryURL.URLByAppendingPathComponent("MyDataBase.sqlite")

Now check if the file exists with checkResourceIsReachableAndReturnError of NSURL.

let fileExists = databaseURL.checkResourceIsReachableAndReturnError(nil)

If you need the error pass the NSError pointer to the parameter.

var error : NSError?
let fileExists = databaseURL.checkResourceIsReachableAndReturnError(&error)
if !fileExists { print(error) }

Swift 3:

In Swift 3 checkResourceIsReachable is marked as can throw

do {
    let fileExists = try databaseURL.checkResourceIsReachable()
    // handle the boolean result
} catch let error as NSError {
    print(error)
}

To consider only the boolean return value and ignore the error use the nil-coalescing operator

let fileExists = (try? databaseURL.checkResourceIsReachable()) ?? false

Questions:
Answers:

It’s pretty user friendly. Just work with NSFileManager’s defaultManager singleton and then use the fileExistsAtPath() method, which simply takes a string as an argument, and returns a Bool, allowing it to be placed directly in the if statement.

let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let documentDirectory = paths[0] as! String
let myFilePath = documentDirectory.stringByAppendingPathComponent("nameOfMyFile")

let manager = NSFileManager.defaultManager()
if (manager.fileExistsAtPath(myFilePath)) {
    // it's here!!
}

Note that the downcast to String isn’t necessary in Swift 2.

Questions:
Answers:

For the benefit of Swift 3 beginners:

  1. Swift 3 has done away with most of the NextStep syntax
  2. So NSURL, NSFilemanager, NSSearchPathForDirectoriesInDomain are no longer used
  3. Instead use URL and FileManager
  4. NSSearchPathForDirectoriesInDomain is not needed
  5. Instead use FileManager.default.urls

Here is a code sample to verify if a file named “database.sqlite” exists in application document directory:

func findIfSqliteDBExists(){

    let docsDir     : URL       = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    let dbPath      : URL       = docsDir.appendingPathComponent("database.sqlite")
    let strDBPath   : String    = dbPath.path
    let fileManager : FileManager   = FileManager.default

    if fileManager.fileExists(atPath:strDBPath){
        print("An sqlite database exists at this path :: \(strDBPath)")
    }else{
        print("SQLite NOT Found at :: \(strDBPath)")
    }

}

Questions:
Answers:

An alternative/recommended Code Pattern in Swift 3 would be:

  1. Use URL instead of FileManager
  2. Use of exception handling

    func verifyIfSqliteDBExists(){
        let docsDir     : URL       = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let dbPath      : URL       = docsDir.appendingPathComponent("database.sqlite")
    
        do{
            let sqliteExists : Bool = try dbPath.checkResourceIsReachable()
            print("An sqlite database exists at this path :: \(dbPath.path)")
    
        }catch{
            print("SQLite NOT Found at :: \(strDBPath)")
        }
    }
    
Questions:
Answers:

Very simple:
If your path is a URL instance convert to string by ‘path’ method.

    let fileManager = FileManager.default
    var isDir: ObjCBool = false
    if fileManager.fileExists(atPath: yourURLPath.path, isDirectory: &isDir) {
        if isDir.boolValue {
            //it's a Directory path
        }else{
            //it's a File path
        }
    }

Questions:
Answers:

You must add a “/” slash before filename, or you get path like “…/DocumentsFilename.jpg”

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