Move database file from bundle to documents folder - FMDB - ios

Question

I'm using FMdatabase.
I want to use a prepared database.
I think I should move database file from bundle to documents folder.
my code:
import FMDB
class DatabaseManager {
private let dbFileName = "kashanmapDB_upgrade_3-4.db"
private var database:FMDatabase!
let TABLE_LOCATION_FA = "LocationInfoFa";
let TABLE_LOCATION_EN = "LocationInfoEn";
let TABLE_GREAT_PEOPLE_FA = "GreatPeopleInfoFa";
let TABLE_GREAT_PEOPLE_EN = "GreatPeopleInfoEn";
let TABLE_TAGS = "Tags";
let TABLE_RELATION_TAG_LOCATION = "RelationTagLocation";
let TABLE_NECESSARY_INFORMATION = "NecessaryInformation";
let TABLE_SLIDER_FA = "SliderFa";
let TABLE_SLIDER_EN = "SliderEn";
let DATABASE_VERSION = 4;
static var LANGUAGE = 1 ; //1:Fa , 2:En
var utilities = Utilities()
init() {
openDatabase()
if(utilities.getData(key: "lang") == "2")
{
DatabaseManager.LANGUAGE = 2
}
}
func copyDatabaseIfNeeded() {
// Move database file from bundle to documents folder
let fileManager = FileManager.default
let documentsUrl = fileManager.urls(for: .documentDirectory,
in: .userDomainMask)
guard documentsUrl.count != 0 else {
return // Could not find documents URL
}
//let finalDatabaseURL = documentsUrl.first!.appendingPathComponent("kashanmapDB_upgrade_3-4.db")
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let finalDatabaseURL = URL(fileURLWithPath: paths).appendingPathComponent(dbFileName)
if !( (try? finalDatabaseURL.checkResourceIsReachable()) ?? false) {
print("DB does not exist in documents folder")
let documentsURL = Bundle.main.resourceURL?.appendingPathComponent("kashanmapDB_upgrade_3-4.db")
do {
try fileManager.copyItem(atPath: (documentsURL?.path)!, toPath: finalDatabaseURL.path)
} catch let error as NSError {
print("Couldn't copy file to final location! Error:\(error.description)")
}
} else {
print("Database file found at path: \(finalDatabaseURL.path)")
}
}
func openDatabase() {
self.copyDatabaseIfNeeded()
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let dbPath = URL(fileURLWithPath: paths).appendingPathComponent(dbFileName)
let str_path = Bundle.main.resourceURL!.appendingPathComponent(dbFileName).path
let database = FMDatabase(path: str_path)
/* Open database read-only. */
if (!(database.open(withFlags: 2))) {
print("Could not open database at \(dbPath).")
} else {
print("opened database")
self.database = database;
}
}
at the first time (when application installed ) I got this error message:
DB does not exist in documents folder
and I always got this message:
Error Domain=FMDatabase Code=8 "attempt to write a readonly database" UserInfo={NSLocalizedDescription=attempt to write a readonly database}

Answer 1

Hmmm... Looking at your code:
func openDatabase() {
self.copyDatabaseIfNeeded()
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let dbPath = URL(fileURLWithPath: paths).appendingPathComponent(dbFileName)
let str_path = Bundle.main.resourceURL!.appendingPathComponent(dbFileName).path
let database = FMDatabase(path: str_path)
/* Open database read-only. */
if (!(database.open(withFlags: 2))) {
print("Could not open database at \(dbPath).")
} else {
print("opened database")
self.database = database;
}
}
It appears you are setting dbPath equal to the path to the file in documents folder, but then you're trying to open database which is at str_path which is equal to the Bundle path.
Maybe just change:
let database = FMDatabase(path: str_path)
to:
let database = FMDatabase(path: dbPath)

Answer 2

Having copied the database, you are trying to open the database from the bundle. Open the one in the Documents folder. If you define the bundle URL inside the if statement that handles the missing database (like shown below), there's no possibility of accidentally grabbing the wrong database.
As an aside, Apple is getting more particular about what gets stored in Documents folder (see iOS Storage Best Practices). You might want to use Application Support folder instead.
let fileURL = try FileManager.default
.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
.appendingPathComponent("test.sqlite")
let fileExists = (try? fileURL.checkResourceIsReachable()) ?? false
if !fileExists {
let bundleURL = Bundle.main.url(forResource: "test", withExtension: "sqlite")!
try FileManager.default.copyItem(at: bundleURL, to: fileURL)
}
let db = FMDatabase(url: fileURL)
guard db.open() else {
print("unable to open")
return
}
Alternatively, it’s often preferred to adopt the “ask for forgiveness rather than permission” strategy. I.e., rather than checking for existence before you open the database every time you open it, just try to open it and handle the file-not-found error scenario (which will happen just once, the first time you try opening it). Bottom line, just try opening the database, and if it fails, copy it from the bundle and try again.
The trick is to supply the SQLITE_OPEN_READWRITE parameter (made available if you import SQLite3) but not the SQLITE_OPEN_CREATE so that it won’t create a blank database if it’s not found that first time you try opening it:
let fileURL = try FileManager.default
.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
.appendingPathComponent("test.sqlite")
let db = FMDatabase(url: fileURL)
if !db.open(withFlags: SQLITE_OPEN_READWRITE) {
let bundleURL = Bundle.main.url(forResource: "test", withExtension: "sqlite")!
try FileManager.default.copyItem(at: bundleURL, to: fileURL)
guard db.open(withFlags: SQLITE_OPEN_READWRITE) else {
print("unable to open")
return
}
}