How to save PDF files from Firebase Storage into App Documents for future use? - ios

Question

I have connected my App with the Firebase Storage where my 19ea PDF files exists.
I would like to download those files and save them locally for future use.
Those PDF files will be used inside UIWebviews but they may need to be updated in time. Therefore, I have configured version control system with Firebase Database, so I will be able to push the newer versions when I update the files in the storage.
So, how I can save those files locally? (to a folder like: user/myapp/Documents/PDF etc?)
Also, how I can check if that folder contains any documents and how to delete them before downloading new files?
Here is what I have got so far.
I appreciate all the help.
// Firebase Storage Connection
static var refStorage:FIRStorageReference?
static var dataPDF = [NSData]()
func newDataDownload(){
// Compare Current Data Version with Online Data Version
if myFirebaseData.localDataVersion < myFirebaseData.onlineDataVersion {
// Set Firebase Storage Reference
myFirebaseData.refStorage = FIRStorage.storage().reference()
for i in 1...myFirebaseData.onlineTotalPDFCount {
// Create a reference to the file you want to download
let pulledPDF = FIRStorage.storage().reference().child("/PDF/\(i).pdf")
// Create local filesystem URL
let localURL = URL(string: "myApp/Documents/PDF/\(i)")!
pulledPDF.data(withMaxSize: myFirebaseData.maxPDFdownloadSize, completion: { (downPDF, err) in
if err == nil {
// Accessed the data
myFirebaseData.dataPDF.append(downPDF! as NSData)
print(myFirebaseData.dataPDF)
} else {
// If there is an error print it
print(err.debugDescription)
}
})
}
}
// If Data is successfully downloaded update Local Data Version
myFirebaseData.localDataVersion = myFirebaseData.onlineDataVersion

Answer 1

Use storageRef.write(toFile: completion:) (docs), like:
// Create a reference to the file you want to download
let pdfRef = storageRef.child("files/file.pdf")
// Create local filesystem URL
let localURL = URL(string: "path/to/local/file.pdf")!
// Download to the local filesystem
let downloadTask = pdfRef.write(toFile: localURL) { url, error in
if let error = error {
// Uh-oh, an error occurred!
} else {
// Local file URL for "path/to/local/file.pdf" is returned
}
}
Note that you can only write to /tmp and /Documents due to app sandboxing requirements (see Downloading Firebase Storage Files Device Issue for an example of how this fails otherwise).