Download Files Locally Part 1
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Download videos and files locally so users can watch them offline
SwiftUI Advanced Handbook
1
Firebase Auth
8:18
2
Read from Firestore
8:01
3
Write to Firestore
5:35
4
Join an Array of Strings
3:33
5
Data from JSON
5:08
6
HTTP Request
6:31
7
WKWebView
5:25
8
Code Highlighting in a WebView
5:11
9
Test for Production in the Simulator
1:43
10
Debug Performance in a WebView
1:57
11
Debug a Crash Log
2:22
12
Simulate a Bad Network
2:11
13
Archive a Build in Xcode
1:28
14
Apollo GraphQL Part I
6:21
15
Apollo GraphQL Part 2
6:43
16
Apollo GraphQL Part 3
5:08
17
Configuration Files in Xcode
4:35
18
App Review
5:43
19
ImagePicker
5:06
20
Compress a UIImage
3:32
21
Firebase Storage
11:11
22
Search Feature
9:13
23
Push Notifications Part 1
5:59
24
Push Notifications Part 2
6:30
25
Push Notifications Part 3
6:13
26
Network Connection
6:49
27
Download Files Locally Part 1
6:05
28
Download Files Locally Part 2
6:02
29
Offline Data with Realm
10:20
30
HTTP Request with Async Await
6:11
31
Xcode Cloud
9:23
32
SceneStorage and TabView
3:52
33
Network Connection Observer
4:37
34
Apollo GraphQL Caching
9:42
35
Create a model from an API response
5:37
36
Multiple type variables in Swift
4:23
37
Parsing Data with SwiftyJSON
9:36
38
ShazamKit
12:38
39
Firebase Remote Config
9:05
Setup
Before starting, if you want to offer this feature for offline mode, I suggest you to read the section on Network Reachability to learn how to create a NetworkReachability class to check the user's internet connection.
Create your class
Let's start by creating a class called DownloadManager. It'll conform to an ObservableObject.
// DownloadManager.swift
final class DownloadManager: ObservableObject {
}Create a isDownloading state
This @Published state will let us know if the video file is currently downloading, so we can show a loading indicator to the user while it's being downloaded.
@Published var isDownloading = falseDownload the file
Create the following downloadFile function.
// DownloadManager.swift
func downloadFile() {
}First, inside of downloadFile, we're setting the isDownloading state to true.
// DownloadManager.swift
func downloadFile() {
isDownloading = true
}Then, we're creating a docsUrl variable. It's a link to the device's file manager, under the user's personal files. Then, we're creating a destinationUrl. The String we're passing to the appendingPathComponent function is the name we'll give to our file.
// DownloadManager.swift
func downloadFile() {
isDownloading = true
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
}Next, we're unwrapping the destinationUrl, to make sure that it exists before continuing. Inside of the if statement, we're checking if the file is already downloaded - if it is, we won't download it again.
// DownloadManager.swift
func downloadFile() {
isDownloading = true
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if FileManager().fileExists(atPath: destinationUrl.path) {
print("File already exists")
isDownloading = false
} else {
}
}
}In the else statement, we're creating an HTTP request to get the video file. Make sure the link you provide is a link to the actual mp4 file. Links to HLS links can't be downloaded with this method. Once we get the data, we're writing it locally. The file will be saved on the device, inside of the application's .ipa file.
func downloadFile() {
isDownloading = true
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if FileManager().fileExists(atPath: destinationUrl.path) {
print("File already exists")
isDownloading = false
} else {
let urlRequest = URLRequest(url: URL(string: "https://file-examples-com.github.io/uploads/2017/04/file_example_MP4_480_1_5MG.mp4")!)
let dataTask = URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
if let error = error {
print("Request error: ", error)
self.isDownloading = false
return
}
guard let response = response as? HTTPURLResponse else { return }
if response.statusCode == 200 {
guard let data = data else {
self.isDownloading = false
return
}
DispatchQueue.main.async {
do {
try data.write(to: destinationUrl, options: Data.WritingOptions.atomic)
DispatchQueue.main.async {
self.isDownloading = false
}
} catch let error {
print("Error decoding: ", error)
self.isDownloading = false
}
}
}
}
dataTask.resume()
}
}
}Delete the file
If you want to allow users to delete the file, use the following function.
func deleteFile() {
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
guard FileManager().fileExists(atPath: destinationUrl.path) else { return }
do {
try FileManager().removeItem(atPath: destinationUrl.path)
self.isDownloaded = false
print("File deleted successfully")
} catch let error {
print("Error while deleting video file: ", error)
}
}
}Check if file is already downloaded
If you need to check if the file is already downloaded, create a @Published variable that tells you if the file is downloaded.
@Published var isDownloaded = falseThen, use the function below. It'll let you know if the file already exists in the FileManager, and save it in the isDownloaded variable.
func checkFileExists() {
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if (FileManager().fileExists(atPath: destinationUrl.path)) {
isDownloaded = true
} else {
isDownloaded = false
}
} else {
isDownloaded = false
}
}Get the downloaded video
To get the downloaded video and get the AVPlayerItem in return, use the following function. Remember to import AVKit at the top of the file. You can read more about integrating a video player in your application with the Play Video with AVPlayer section of this handbook. When creating your AVPlayer instance, simply replace url with the playerItem you get from this function.
// DownloadManager.swift
func getVideoFileAsset() -> AVPlayerItem? {
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if (FileManager().fileExists(atPath: destinationUrl.path)) {
let avAssest = AVAsset(url: destinationUrl)
return AVPlayerItem(asset: avAssest)
} else {
return nil
}
} else {
return nil
}
}Final code
Find below the final code for the DownloadManager class.
import Foundation
import AVKit
final class DownloadManager: ObservableObject {
@Published var isDownloading = false
@Published var isDownloaded = false
func downloadFile() {
print("downloadFile")
isDownloading = true
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if (FileManager().fileExists(atPath: destinationUrl.path)) {
print("File already exists")
isDownloading = false
} else {
let urlRequest = URLRequest(url: URL(string: "https://file-examples-com.github.io/uploads/2017/04/file_example_MP4_480_1_5MG.mp4")!)
let dataTask = URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
if let error = error {
print("Request error: ", error)
self.isDownloading = false
return
}
guard let response = response as? HTTPURLResponse else { return }
if response.statusCode == 200 {
guard let data = data else {
self.isDownloading = false
return
}
DispatchQueue.main.async {
do {
try data.write(to: destinationUrl, options: Data.WritingOptions.atomic)
DispatchQueue.main.async {
self.isDownloading = false
self.isDownloaded = true
}
} catch let error {
print("Error decoding: ", error)
self.isDownloading = false
}
}
}
}
dataTask.resume()
}
}
}
func deleteFile() {
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
guard FileManager().fileExists(atPath: destinationUrl.path) else { return }
do {
try FileManager().removeItem(atPath: destinationUrl.path)
print("File deleted successfully")
isDownloaded = false
} catch let error {
print("Error while deleting video file: ", error)
}
}
}
func checkFileExists() {
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if (FileManager().fileExists(atPath: destinationUrl.path)) {
isDownloaded = true
} else {
isDownloaded = false
}
} else {
isDownloaded = false
}
}
func getVideoFileAsset() -> AVPlayerItem? {
let docsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let destinationUrl = docsUrl?.appendingPathComponent("myVideo.mp4")
if let destinationUrl = destinationUrl {
if (FileManager().fileExists(atPath: destinationUrl.path)) {
let avAssest = AVAsset(url: destinationUrl)
return AVPlayerItem(asset: avAssest)
} else {
return nil
}
} else {
return nil
}
}
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1
Firebase Auth
How to install Firebase authentification to your Xcode project
8:18
2
Read from Firestore
Install Cloud Firestore in your application to fetch and read data from a collection
8:01
3
Write to Firestore
Save the data users input in your application in a Firestore collection
5:35
4
Join an Array of Strings
Turn your array into a serialized String
3:33
5
Data from JSON
Load data from a JSON file into your SwiftUI application
5:08
6
HTTP Request
Create an HTTP Get Request to fetch data from an API
6:31
7
WKWebView
Integrate an HTML page into your SwiftUI application using WKWebView and by converting Markdown into HTML
5:25
8
Code Highlighting in a WebView
Use Highlight.js to convert your code blocks into beautiful highlighted code in a WebView
5:11
9
Test for Production in the Simulator
Build your app on Release scheme to test for production
1:43
10
Debug Performance in a WebView
Enable Safari's WebInspector to debug the performance of a WebView in your application
1:57
11
Debug a Crash Log
Learn how to debug a crash log from App Store Connect in Xcode
2:22
12
Simulate a Bad Network
Test your SwiftUI application by simulating a bad network connection with Network Link Conditionner
2:11
13
Archive a Build in Xcode
Archive a build for beta testing or to release in the App Store
1:28
14
Apollo GraphQL Part I
Install Apollo GraphQL in your project to fetch data from an API
6:21
15
Apollo GraphQL Part 2
Make a network call to fetch your data and process it into your own data type
6:43
16
Apollo GraphQL Part 3
Display the data fetched with Apollo GraphQL in your View
5:08
17
Configuration Files in Xcode
Create configuration files and add variables depending on the environment - development or production
4:35
18
App Review
Request an app review from your user for the AppStore
5:43
19
ImagePicker
Create an ImagePicker to choose a photo from the library or take a photo from the camera
5:06
20
Compress a UIImage
Compress a UIImage by converting it to JPEG, reducing its size and quality
3:32
21
Firebase Storage
Upload, delete and list files in Firebase Storage
11:11
22
Search Feature
Implement a search feature to filter through your content in your SwiftUI application
9:13
23
Push Notifications Part 1
Set up Firebase Cloud Messaging as a provider server to send push notifications to your users
5:59
24
Push Notifications Part 2
Create an AppDelegate to ask permission to send push notifications using Apple Push Notifications service and Firebase Cloud Messaging
6:30
25
Push Notifications Part 3
Tie everything together and test your push notifications feature in production
6:13
26
Network Connection
Verify the network connection of your user to perform tasks depending on their network's reachability
6:49
27
Download Files Locally Part 1
Download videos and files locally so users can watch them offline
6:05
28
Download Files Locally Part 2
Learn how to use the DownloadManager class in your views for offline video viewing
6:02
29
Offline Data with Realm
Save your SwiftUI data into a Realm so users can access them offline
10:20
30
HTTP Request with Async Await
Create an HTTP get request function using async await
6:11
31
Xcode Cloud
Automate workflows with Xcode Cloud
9:23
32
SceneStorage and TabView
Use @SceneStorage with TabView for better user experience on iPad
3:52
33
Network Connection Observer
Observe the network connection state using NWPathMonitor
4:37
34
Apollo GraphQL Caching
Cache data for offline availability with Apollo GraphQL
9:42
35
Create a model from an API response
Learn how to create a SwiftUI model out of the response body of an API
5:37
36
Multiple type variables in Swift
Make your models conform to the same protocol to create multiple type variables
4:23
37
Parsing Data with SwiftyJSON
Make API calls and easily parse data with this JSON package
9:36
38
ShazamKit
Build a simple Shazam clone and perform music recognition
12:38
39
Firebase Remote Config
Deliver changes to your app on the fly remotely
9:05
Meet the instructor
We all try to be consistent with our way of teaching step-by-step, providing source files and prioritizing design in our courses.
Stephanie Diep
iOS and Web developer
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