Initializing an s3 client in AWS SDK for Swift - ios

Question

The docs for the AWS SDk for Swift describe how to instantiate a service client:
let s3Client = try S3Client(region: "us-east-1")
However since this statement can throw errors it needs to be wrapped in a do catch block as shown on a separate documentation page:
do {
let s3 = try S3Client(region: "af-south-1")
// .....
} catch {
dump(error, name: "Error accessing S3 service")
exit(1)
}
I've created a public S3Manager class that will contain the specific functions I want to use in my code for manipulating s3 buckets. Typically I would instantiate the client in the class initializer but since it must be wrapped in a do catch block I have taken a different approach:
public class S3manager : ObservableObject {
public var client: S3Client?
public func initializeClient() {
do {
client = try S3Client(region: "us-west-2")
} catch {
fatalError("Error creating S3 client: \(error)")
}
}
public func listBucketFiles(bucket: String) async throws -> [String] {
if let clientInstance = client {
// ...
}
}
}
In my views I will reference the class as a StateObject or ObservedObject as appropriate and be certain to call initializeClient before calling any other methods I implement in the class (in the initial view's onAppear() method for example) Is this the best approach though?

Answer 1

I can't confirm that the code below works exactly as expected because the SDK is not finding my credentials in ~/.aws/credentialsor as environment variables, but I changed my approach to contain all of thes3` logic in it's own respective class:
import Foundation
import AWSS3
import ClientRuntime
import AWSClientRuntime
public class S3manager : ObservableObject {
private var client: S3Client?
public var files: [String]?
init() {
Task(priority: .high) {
do {
client = try S3Client(region: "us-west-2")
files = try await listBucketFiles(bucket: "bucket_name")
} catch {
print(error)
}
}
}
// from https://docs.aws.amazon.com/sdk-for-swift/latest/developer-guide/examples-s3-objects.html
public func listBucketFiles(bucket: String) async throws -> [String] {
if let clientInstance = client {
let input = ListObjectsV2Input(
bucket: bucket
)
let output = try await clientInstance.listObjectsV2(input: input)
var names: [String] = []
guard let objList = output.contents else {
return []
}
for obj in objList {
if let objName = obj.key {
names.append(objName)
}
}
return names
} else {
print("Client has not been initialized!")
return [String]()
}
}
}
This has the advantage that in ContentView I can simply reference the class member as follows:
struct ContentView: View {
#StateObject private var s3 = S3manager()
var body: some View {
VStack {
List(s3.files ?? ["Content Loading..."], id: \.self) {
Text($0)
}
}
}
}