download progress

Author: ethanndickson

Coder-Desktop/VPN/Manager.swift

@@ -35,7 +35,13 @@ actor Manager {
             // Timeout after 5 minutes, or if there's no data for 60 seconds
             sessionConfig.timeoutIntervalForRequest = 60
             sessionConfig.timeoutIntervalForResource = 300
-            try await download(src: dylibPath, dest: dest, urlSession: URLSession(configuration: sessionConfig))
+            try await download(
+                src: dylibPath,
+                dest: dest,
+                urlSession: URLSession(configuration: sessionConfig)
+            ) { progress in
+                pushProgress(msg: "Downloading library...\n\(progress.description)")
+            }
         } catch {
             throw .download(error)
         }

Coder-Desktop/VPNLib/Download.swift

@@ -125,47 +125,13 @@ public class SignatureValidator {
     }
 }
 
-public func download(src: URL, dest: URL, urlSession: URLSession) async throws(DownloadError) {
-    var req = URLRequest(url: src)
-    if FileManager.default.fileExists(atPath: dest.path) {
-        if let existingFileData = try? Data(contentsOf: dest, options: .mappedIfSafe) {
-            req.setValue(etag(data: existingFileData), forHTTPHeaderField: "If-None-Match")
-        }
-    }
-    // TODO: Add Content-Length headers to coderd, add download progress delegate
-    let tempURL: URL
-    let response: URLResponse
-    do {
-        (tempURL, response) = try await urlSession.download(for: req)
-    } catch {
-        throw .networkError(error, url: src.absoluteString)
-    }
-    defer {
-        if FileManager.default.fileExists(atPath: tempURL.path) {
-            try? FileManager.default.removeItem(at: tempURL)
-        }
-    }
-
-    guard let httpResponse = response as? HTTPURLResponse else {
-        throw .invalidResponse
-    }
-    guard httpResponse.statusCode != 304 else {
-        // We already have the latest dylib downloaded on disk
-        return
-    }
-
-    guard httpResponse.statusCode == 200 else {
-        throw .unexpectedStatusCode(httpResponse.statusCode)
-    }
-
-    do {
-        if FileManager.default.fileExists(atPath: dest.path) {
-            try FileManager.default.removeItem(at: dest)
-        }
-        try FileManager.default.moveItem(at: tempURL, to: dest)
-    } catch {
-        throw .fileOpError(error)
-    }
+public func download(
+    src: URL,
+    dest: URL,
+    urlSession: URLSession,
+    progressUpdates: ((DownloadProgress) -> Void)? = nil
+) async throws(DownloadError) {
+    try await DownloadManager().download(src: src, dest: dest, urlSession: urlSession, progressUpdates: progressUpdates)
 }
 
 func etag(data: Data) -> String {
@@ -195,3 +161,104 @@ public enum DownloadError: Error {
 
     public var localizedDescription: String { description }
 }
+
+// The async `URLSession.download` api ignores the passed-in delegate, so we
+// wrap the older delegate methods in an async adapter with a continuation.
+private final class DownloadManager: NSObject, @unchecked Sendable {
+    private var continuation: CheckedContinuation<Void, Error>!
+    private var progressHandler: ((DownloadProgress) -> Void)?
+    private var dest: URL!
+
+    func download(
+        src: URL,
+        dest: URL,
+        urlSession: URLSession,
+        progressUpdates: ((DownloadProgress) -> Void)?
+    ) async throws(DownloadError) {
+        var req = URLRequest(url: src)
+        if FileManager.default.fileExists(atPath: dest.path) {
+            if let existingFileData = try? Data(contentsOf: dest, options: .mappedIfSafe) {
+                req.setValue(etag(data: existingFileData), forHTTPHeaderField: "If-None-Match")
+            }
+        }
+
+        let downloadTask = urlSession.downloadTask(with: req)
+        progressHandler = progressUpdates
+        self.dest = dest
+        downloadTask.delegate = self
+        do {
+            try await withCheckedThrowingContinuation { continuation in
+                self.continuation = continuation
+                downloadTask.resume()
+            }
+        } catch let error as DownloadError {
+            throw error
+        } catch {
+            throw .networkError(error, url: src.absoluteString)
+        }
+    }
+}
+
+extension DownloadManager: URLSessionDownloadDelegate {
+    // Progress
+    func urlSession(
+        _: URLSession,
+        downloadTask: URLSessionDownloadTask,
+        didWriteData _: Int64,
+        totalBytesWritten: Int64,
+        totalBytesExpectedToWrite _: Int64
+    ) {
+        let maybeLength = (downloadTask.response as? HTTPURLResponse)?
+            .value(forHTTPHeaderField: "X-Original-Content-Length")
+            .flatMap(Int64.init)
+        progressHandler?(.init(totalBytesWritten: totalBytesWritten, totalBytesToWrite: maybeLength))
+    }
+
+    // Completion
+    func urlSession(_: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
+        guard let httpResponse = downloadTask.response as? HTTPURLResponse else {
+            continuation.resume(throwing: DownloadError.invalidResponse)
+            return
+        }
+        guard httpResponse.statusCode != 304 else {
+            // We already have the latest dylib downloaded in dest
+            continuation.resume()
+            return
+        }
+
+        guard httpResponse.statusCode == 200 else {
+            continuation.resume(throwing: DownloadError.unexpectedStatusCode(httpResponse.statusCode))
+            return
+        }
+
+        do {
+            if FileManager.default.fileExists(atPath: dest.path) {
+                try FileManager.default.removeItem(at: dest)
+            }
+            try FileManager.default.moveItem(at: location, to: dest)
+        } catch {
+            continuation.resume(throwing: DownloadError.fileOpError(error))
+        }
+
+        continuation.resume()
+    }
+
+    // Failure
+    func urlSession(_: URLSession, task _: URLSessionTask, didCompleteWithError error: Error?) {
+        if let error {
+            continuation.resume(throwing: error)
+        }
+    }
+}
+
+public struct DownloadProgress: Sendable, CustomStringConvertible {
+    let totalBytesWritten: Int64
+    let totalBytesToWrite: Int64?
+
+    public var description: String {
+        let fmt = ByteCountFormatter()
+        let done = fmt.string(fromByteCount: totalBytesWritten)
+        let total = totalBytesToWrite.map { fmt.string(fromByteCount: $0) } ?? "Unknown"
+        return "\(done) / \(total)"
+    }
+}