introduced AuthenticationProviding interface to permit netrc injection to Downloader

Author: sstadelman

Sources/TSCUtility/Downloader.swift

@@ -43,11 +43,13 @@ public protocol Downloader {
     /// - Parameters:
     ///   - url: The `URL` to the file to download.
     ///   - destination: The `AbsolutePath` to download the file to.
+    ///   - authorizationProvider: Optional provider supplying `Authorization` header to be added to `URLRequest`.
     ///   - progress: A closure to receive the download's progress as number of bytes.
     ///   - completion: A closure to be notifed of the completion of the download.
     func downloadFile(
         at url: Foundation.URL,
         to destination: AbsolutePath,
+        withAuthorizationProvider authorizationProvider: AuthorizationProviding?,
         progress: @escaping Progress,
         completion: @escaping Completion
     )
@@ -109,33 +111,24 @@ public final class FoundationDownloader: NSObject, Downloader {
     public func downloadFile(
         at url: Foundation.URL,
         to destination: AbsolutePath,
+        withAuthorizationProvider authorizationProvider: AuthorizationProviding? = nil,
         progress: @escaping Downloader.Progress,
         completion: @escaping Downloader.Completion
     ) {
-        queue.addOperation {
+        queue.addOperation { [self] in
             var request = URLRequest(url: url)
 
-            if #available(OSX 10.13, *) {
-                switch Netrc.load() {
-                case let .success(netrc):
-                    if let authorization = netrc.authorization(for: url) {
-                        request.addValue(authorization, forHTTPHeaderField: "Authorization")
-                    }
-                case .failure(_):
-                    break // Failure cases unhandled
-                }
-            } else {
-                // Netrc loading is not supported for OSX < 10.13; continue with task-
-                // initialization without attempting to append netrc-based credentials.
+            if let authorization = authorizationProvider?.authorization(for: url) {
+                request.addValue(authorization, forHTTPHeaderField: "Authorization")
             }
 
-            let task = self.session.downloadTask(with: request)
+            let task = session.downloadTask(with: request)
             let download = Download(
                 task: task,
                 destination: destination,
                 progress: progress,
                 completion: completion)
-            self.downloads[task.taskIdentifier] = download
+            downloads[task.taskIdentifier] = download
             task.resume()
         }
     }

Sources/TSCUtility/Netrc.swift

@@ -1,8 +1,22 @@
 import Foundation
+import TSCBasic
+
+
+/// Supplies `Authorization` header, typically to be appended to `URLRequest`
+public protocol AuthorizationProviding {
+    /// Optional `Authorization` header, likely added to `URLRequest`
+    func authorization(for url: Foundation.URL) -> String?
+}
+
+extension AuthorizationProviding {
+    func authorization(for url: Foundation.URL) -> String? {
+        return nil
+    }
+}
 
 @available (OSX 10.13, *)
 /// Container of parsed netrc connection settings
-public struct Netrc {
+public struct Netrc: AuthorizationProviding {
 
     /// Representation of `machine` connection settings & `default` connection settings.  If `default` connection settings present, they will be last element.
     public let machines: [Machine]
@@ -11,10 +25,10 @@ public struct Netrc {
         self.machines = machines
     }
 
-    /// Testing API.  Not for productive use.
-    /// See:  [Remove @testable from codebase](https://github.com/apple/swift-package-manager/commit/b6349d516d2f9b2f26ddae9de2c594ede24af7d6)
-    public static var _mock: Netrc? = nil
-    
+//    /// Testing API.  Not for productive use.
+//    /// See:  [Remove @testable from codebase](https://github.com/apple/swift-package-manager/commit/b6349d516d2f9b2f26ddae9de2c594ede24af7d6)
+//    public static var _mock: Netrc? = nil
+        
     /// Basic authorization header string
     /// - Parameter url: URI of network resource to be accessed
     /// - Returns: (optional) Basic Authorization header string to be added to the request
@@ -29,13 +43,15 @@ public struct Netrc {
     ///
     /// - Parameter fileURL: Location of netrc file, defaults to `~/.netrc`
     /// - Returns: `Netrc` container with parsed connection settings, or error
-    public static func load(from fileURL: Foundation.URL = Foundation.URL(fileURLWithPath: "\(NSHomeDirectory())/.netrc")) -> Result<Netrc, Netrc.Error> {
-        
-        guard _mock == nil else { return .success(_mock!) }
+    public static func load(fromFileAtPath filePath: AbsolutePath? = nil) -> Result<Netrc, Netrc.Error> {
+                
+        guard let filePath = filePath ?? AbsolutePath("\(NSHomeDirectory())/.netrc") else {
+            return .failure(.invalidFilePath)
+        }
 
-        guard FileManager.default.fileExists(atPath: fileURL.path) else { return .failure(.fileNotFound(fileURL)) }
-        guard FileManager.default.isReadableFile(atPath: fileURL.path),
-            let fileContents = try? String(contentsOf: fileURL, encoding: .utf8) else { return .failure(.unreadableFile(fileURL)) }
+        guard FileManager.default.fileExists(atPath: filePath.pathString) else { return .failure(.fileNotFound(filePath)) }
+        guard FileManager.default.isReadableFile(atPath: filePath.pathString),
+              let fileContents = try? String(contentsOf: filePath.asURL, encoding: .utf8) else { return .failure(.unreadableFile(filePath)) }
 
         return Netrc.from(fileContents)
     }
@@ -84,13 +100,13 @@ public struct Netrc {
 public extension Netrc {
 
     enum Error: Swift.Error {
-        case fileNotFound(Foundation.URL)
-        case unreadableFile(Foundation.URL)
+        case invalidFilePath
+        case fileNotFound(AbsolutePath)
+        case unreadableFile(AbsolutePath)
         case machineNotFound
         case invalidDefaultMachinePosition
     }
 
-    
     /// Representation of connection settings
     /// - important: Default connection settings are stored in machine named `default`
     struct Machine: Equatable {

Tests/TSCUtilityTests/DownloaderTests.swift

@@ -18,12 +18,6 @@ import FoundationNetworking
 #endif
 
 class DownloaderTests: XCTestCase {
-    
-    override func tearDown() {
-        if #available(OSX 10.13, *) {
-            Netrc._mock = nil
-        }
-    }
 
     func testSuccess() {
       // FIXME: Remove once https://github.com/apple/swift-corelibs-foundation/pull/2593 gets inside a toolchain.
@@ -89,7 +83,6 @@ class DownloaderTests: XCTestCase {
         }
         let authData = "anonymous:qwerty".data(using: .utf8)!
         let testAuthHeader = "Basic \(authData.base64EncodedString())"
-        Netrc._mock = netrc
 
       #if os(macOS)
         let configuration = URLSessionConfiguration.default
@@ -106,7 +99,7 @@ class DownloaderTests: XCTestCase {
             let successExpectation = XCTestExpectation(description: "success")
             MockAuthenticatingURLProtocol.notifyDidStartLoading(for: url, completion: { didStartLoadingExpectation.fulfill() })
 
-            downloader.downloadFile(at: url, to: destination, progress: { bytesDownloaded, totalBytesToDownload in
+            downloader.downloadFile(at: url, to: destination, withAuthorizationProvider: netrc, progress: { bytesDownloaded, totalBytesToDownload in
 
                 XCTAssertEqual(MockAuthenticatingURLProtocol.authenticationHeader(for: url), testAuthHeader)
 
@@ -156,7 +149,6 @@ class DownloaderTests: XCTestCase {
         }
         let authData = "default:default".data(using: .utf8)!
         let testAuthHeader = "Basic \(authData.base64EncodedString())"
-        Netrc._mock = netrc
 
       #if os(macOS)
         let configuration = URLSessionConfiguration.default
@@ -173,7 +165,7 @@ class DownloaderTests: XCTestCase {
             let successExpectation = XCTestExpectation(description: "success")
             MockAuthenticatingURLProtocol.notifyDidStartLoading(for: url, completion: { didStartLoadingExpectation.fulfill() })
 
-            downloader.downloadFile(at: url, to: destination, progress: { bytesDownloaded, totalBytesToDownload in
+            downloader.downloadFile(at: url, to: destination, withAuthorizationProvider: netrc, progress: { bytesDownloaded, totalBytesToDownload in
 
                 XCTAssertEqual(MockAuthenticatingURLProtocol.authenticationHeader(for: url), testAuthHeader)