Remove dependency on Swift-NIO SSL

This removes Swift-DocC's dependency on Swift-NIO SSL.

The removal is motivated by Swift-NIO SSL deprecating support for CentOS 7 due
to BoringSSL removing support for CentOS 7.

The Swift-NIO SSL dependency is currently used to support running a
documentation preview server over HTTPS which allows users to preview content
on a secondary device while authoring it on a primary device since
many OS's won't allow accessing non-local content over HTTP.

With the introduction of `--transform-for-static-hosting` and the subsequent
enabling of that feature by default, there's less need for Swift-DocC to ship
a solution for this niche feature out-of-the-box since standard command-line
based preview servers now support serving DocC archives with minimal additional
configuration.

Resolves rdar://93197483.

Author: ethan-kusters

NOTICE.txt

@@ -31,15 +31,6 @@ This product contains Swift NIO.
 
 ---
 
-This product contains Swift NIO SSL.
-
-  * LICENSE (Apache License 2.0):
-    * https://www.apache.org/licenses/LICENSE-2.0
-  * HOMEPAGE:
-    * https://github.com/apple/swift-nio-ssl
-
----
-
 This product contains Swift Crypto.
 
   * LICENSE (Apache License 2.0):

Package.resolved

@@ -72,15 +72,6 @@
           "revision": "1d425b0851ffa2695d488cce1d68df2539f42500",
           "version": "2.31.2"
         }
-      },
-      {
-        "package": "swift-nio-ssl",
-        "repositoryURL": "https://github.com/apple/swift-nio-ssl.git",
-        "state": {
-          "branch": null,
-          "revision": "2e74773972bd6254c41ceeda827f229bccbf1c0f",
-          "version": "2.15.0"
-        }
       }
     ]
   },

Package.swift

@@ -60,7 +60,6 @@ let package = Package(
             name: "SwiftDocCUtilities",
             dependencies: [
                 "SwiftDocC",
-                .product(name: "NIOSSL", package: "swift-nio-ssl"),
                 .product(name: "NIOHTTP1", package: "swift-nio"),
                 .product(name: "ArgumentParser", package: "swift-argument-parser")
             ]),
@@ -120,7 +119,6 @@ if ProcessInfo.processInfo.environment["SWIFTCI_USE_LOCAL_DEPS"] == nil {
     // Building standalone, so fetch all dependencies remotely.
     package.dependencies += [
         .package(url: "https://github.com/apple/swift-nio.git", .upToNextMinor(from: "2.31.2")),
-        .package(url: "https://github.com/apple/swift-nio-ssl.git", .upToNextMinor(from: "2.15.0")),
         .package(name: "swift-markdown", url: "https://github.com/apple/swift-markdown.git", .branch("main")),
         .package(name: "CLMDB", url: "https://github.com/apple/swift-lmdb.git", .branch("main")),
         .package(url: "https://github.com/apple/swift-argument-parser", .upToNextMinor(from: "1.0.1")),
@@ -138,7 +136,6 @@ if ProcessInfo.processInfo.environment["SWIFTCI_USE_LOCAL_DEPS"] == nil {
     // Building in the Swift.org CI system, so rely on local versions of dependencies.
     package.dependencies += [
         .package(path: "../swift-nio"),
-        .package(path: "../swift-nio-ssl"),
         .package(path: "../swift-markdown"),
         .package(name: "CLMDB", path: "../swift-lmdb"),
         .package(path: "../swift-argument-parser"),

Sources/SwiftDocCUtilities/Action/Actions/PreviewAction.swift

@@ -52,19 +52,12 @@ public final class PreviewAction: Action, RecreatingContext {
 
     var logHandle = LogHandle.standardOutput
 
-    let tlsCertificateKey: URL?
-    let tlsCertificateChain: URL?
-    let serverUsername: String?
-    let serverPassword: String?
     let port: Int
 
     var convertAction: ConvertAction
 
     public var setupContext: ((inout DocumentationContext) -> Void)?
     private var previewPaths: [String] = []
-    private var runSecure: Bool {
-        return tlsCertificateKey != nil && tlsCertificateChain != nil
-    }
 
     // Use for testing to override binding to a system port
     var bindServerToSocketPath: String?
@@ -80,15 +73,7 @@ public final class PreviewAction: Action, RecreatingContext {
 
     /// Creates a new preview action from the given parameters.
     ///
-    /// The `tlsCertificateKey`, `tlsCertificateChain`, `serverUsername`,  and `serverPassword`
-    /// parameters are optional, but if you provide one, all four are expected. They are used by the preview server
-    /// to serve content on the local network over SSL.
-    ///
     /// - Parameters:
-    ///   - tlsCertificateKey: The path to the TLS certificate key used by the preview server for SSL configuration.
-    ///   - tlsCertificateChain: The path to the TLS certificate chain used by the preview server for SSL configuration.
-    ///   - serverUsername: The username used by the preview server for HTTP authentication.
-    ///   - serverPassword: The password used by the preview server for HTTP authentication.
     ///   - port: The port number used by the preview server.
     ///   - convertAction: The action used to convert the documentation bundle before preview.
     ///   On macOS, this action will be reused to convert documentation each time the source is modified.
@@ -98,8 +83,7 @@ public final class PreviewAction: Action, RecreatingContext {
     ///     is performed.
     /// - Throws: If an error is encountered while initializing the documentation context.
     public init(
-        tlsCertificateKey: URL?, tlsCertificateChain: URL?, serverUsername: String?,
-        serverPassword: String?, port: Int,
+        port: Int,
         createConvertAction: @escaping () throws -> ConvertAction,
         workspace: DocumentationWorkspace = DocumentationWorkspace(),
         context: DocumentationContext? = nil,
@@ -110,10 +94,6 @@ public final class PreviewAction: Action, RecreatingContext {
         }
 
         // Initialize the action context.
-        self.tlsCertificateKey = tlsCertificateKey
-        self.tlsCertificateChain = tlsCertificateChain
-        self.serverUsername = serverUsername
-        self.serverPassword = serverPassword
         self.port = port
         self.createConvertAction = createConvertAction
         self.convertAction = try createConvertAction()
@@ -123,6 +103,24 @@ public final class PreviewAction: Action, RecreatingContext {
         self.context = try context ?? DocumentationContext(dataProvider: workspace, diagnosticEngine: engine)
         self.printHTMLTemplatePath = printTemplatePath
     }
+    
+    @available(*, deprecated, message: "TLS support has been removed.")
+    public convenience init(
+        tlsCertificateKey: URL?, tlsCertificateChain: URL?, serverUsername: String?,
+        serverPassword: String?, port: Int,
+        createConvertAction: @escaping () throws -> ConvertAction,
+        workspace: DocumentationWorkspace = DocumentationWorkspace(),
+        context: DocumentationContext? = nil,
+        printTemplatePath: Bool = true) throws
+    {
+        try self.init(
+            port: port,
+            createConvertAction: createConvertAction,
+            workspace: workspace,
+            context: context,
+            printTemplatePath: printTemplatePath
+        )
+    }
 
     /// Converts a documentation bundle and starts a preview server to render the result of that conversion.
     ///
@@ -164,20 +162,12 @@ public final class PreviewAction: Action, RecreatingContext {
         // Preview the output and monitor the source bundle for changes.
         do {
             print(String(repeating: "=", count: 40), to: &logHandle)
-            if runSecure, let serverUsername = serverUsername, let serverPassword = serverPassword {
-                print("Starting TLS-Enabled Web Server", to: &logHandle)
-                printPreviewAddresses(base: URL(string: "https://\(ProcessInfo.processInfo.hostName):\(port)")!)
-                print("\tUsername: \(serverUsername)", to: &logHandle)
-                print("\tPassword: \(serverPassword)", to: &logHandle)
-                
-            } else {
-                print("Starting Local Preview Server", to: &logHandle)
-                printPreviewAddresses(base: URL(string: "http://localhost:\(port)")!)
-            }
+            print("Starting Local Preview Server", to: &logHandle)
+            printPreviewAddresses(base: URL(string: "http://localhost:\(port)")!)
             print(String(repeating: "=", count: 40), to: &logHandle)
 
             let to: PreviewServer.Bind = bindServerToSocketPath.map { .socket(path: $0) } ?? .localhost(port: port)
-            servers[serverIdentifier] = try PreviewServer(contentURL: convertAction.targetDirectory, bindTo: to, username: serverUsername, password: serverPassword, tlsCertificateChainURL: tlsCertificateChain, tlsCertificateKeyURL: tlsCertificateKey, logHandle: &logHandle)
+            servers[serverIdentifier] = try PreviewServer(contentURL: convertAction.targetDirectory, bindTo: to, logHandle: &logHandle)
 
             // When the user stops docc - stop the preview server first before exiting.
             trapSignals()

Sources/SwiftDocCUtilities/ArgumentParsing/ActionExtensions/PreviewAction+CommandInitialization.swift

@@ -23,10 +23,6 @@ extension PreviewAction {
     {
         // Initialize the `PreviewAction` from the options provided by the `Preview` command
         try self.init(
-            tlsCertificateKey: previewOptions.externalConnectionOptions.tlsCertificateKeyURL,
-            tlsCertificateChain: previewOptions.externalConnectionOptions.tlsCertificateChainURL,
-            serverUsername: previewOptions.externalConnectionOptions.username,
-            serverPassword: previewOptions.externalConnectionOptions.password,
             port: previewOptions.port,
             createConvertAction: {
                 try ConvertAction(

Sources/SwiftDocCUtilities/ArgumentParsing/ArgumentValidation/CredentialArgumentValidator.swift

@@ -35,18 +35,6 @@ public struct PreviewOptions: ParsableArguments {
             valueName: "port-number"))
     public var port: Int = 8000
 
-    /// The options used when configuring the preview server for external connections.
-    ///
-    /// This group of options is only considered valid if either none of
-    /// the ``PreviewExternalConnectionOptions/username``, ``PreviewExternalConnectionOptions/password``,
-    /// ``PreviewExternalConnectionOptions/tlsCertificateChainURL``, ``PreviewExternalConnectionOptions/tlsCertificateKeyURL``
-    /// values were provided **or** if they all were.
-    ///
-    /// If the ``PreviewExternalConnectionOptions/externalConnectionsAreEnabled`` Boolean value
-    /// is true, then **all** four values were provided and validated.
-    @OptionGroup()
-    public var externalConnectionOptions: PreviewExternalConnectionOptions
-    
     public mutating func validate() throws {
         // Check that a valid port has been provided
         guard port > 1023 else {