Implement AuthenticationMiddleware (#117)

Package.swift

@@ -204,5 +204,10 @@ let package = Package(
       dependencies: ["SyntaxKit", "DocumentationHarness"],
       swiftSettings: swiftSettings
     ),
+    .testTarget(
+      name: "AiSTKitTests",
+      dependencies: ["AiSTKit"],
+      swiftSettings: swiftSettings
+    ),
   ]
 )

Sources/AiSTKit/AuthenticationMiddleware.swift

@@ -0,0 +1,96 @@
+//
+//  AuthenticationMiddleware.swift
+//  SyntaxKit
+//
+//  Created by Leo Dion.
+//  Copyright © 2026 BrightDigit.
+//
+//  Permission is hereby granted, free of charge, to any person
+//  obtaining a copy of this software and associated documentation
+//  files (the “Software”), to deal in the Software without
+//  restriction, including without limitation the rights to use,
+//  copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the
+//  Software is furnished to do so, subject to the following
+//  conditions:
+//
+//  The above copyright notice and this permission notice shall be
+//  included in all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+//  OTHER DEALINGS IN THE SOFTWARE.
+//
+
+public import HTTPTypes
+public import OpenAPIRuntime
+
+#if os(Linux)
+  @preconcurrency public import struct Foundation.URL
+#else
+  public import struct Foundation.URL
+#endif
+
+/// OpenAPI client middleware that adds Anthropic API authentication headers.
+///
+/// Injects the `x-api-key` and `anthropic-version` headers into every
+/// outgoing request before forwarding it to the next handler in the chain.
+public struct AuthenticationMiddleware: ClientMiddleware {
+  /// The Anthropic API version sent with every request.
+  private static let anthropicVersion = "2023-06-01"
+
+  /// The `x-api-key` header name, constructed once. `"x-api-key"` is a valid
+  /// RFC 9110 token, so this is always non-`nil`.
+  private static let apiKeyFieldName = HTTPField.Name("x-api-key")
+
+  /// The `anthropic-version` header name, constructed once. `"anthropic-version"`
+  /// is a valid RFC 9110 token, so this is always non-`nil`.
+  private static let anthropicVersionFieldName = HTTPField.Name("anthropic-version")
+
+  /// The Anthropic API key used to authenticate requests.
+  private let apiKey: String
+
+  /// Creates a middleware that authenticates requests with the given API key.
+  /// - Parameter apiKey: The Anthropic API key to send in the `x-api-key` header.
+  public init(apiKey: String) {
+    self.apiKey = apiKey
+  }
+
+  /// Adds the Anthropic authentication headers, then forwards the request.
+  ///
+  /// Any `x-api-key` or `anthropic-version` header already present on the
+  /// request is silently overwritten with this middleware's values.
+  /// - Parameters:
+  ///   - request: The outgoing HTTP request.
+  ///   - body: The outgoing HTTP request body, if any.
+  ///   - baseURL: The base URL of the server.
+  ///   - operationID: The OpenAPI operation identifier for the request.
+  ///   - next: The next handler in the middleware chain.
+  /// - Returns: The HTTP response and body from the next handler.
+  /// - Throws: Any error thrown by the `next` handler.
+  public func intercept(
+    _ request: HTTPRequest,
+    body: HTTPBody?,
+    baseURL: URL,
+    operationID: String,
+    next: @Sendable (HTTPRequest, HTTPBody?, URL) async throws -> (HTTPResponse, HTTPBody?)
+  ) async throws -> (HTTPResponse, HTTPBody?) {
+    var request = request
+    if let apiKeyFieldName = Self.apiKeyFieldName {
+      request.headerFields[apiKeyFieldName] = apiKey
+    } else {
+      assertionFailure("\"x-api-key\" is a valid header name and must never be nil.")
+    }
+    if let anthropicVersionFieldName = Self.anthropicVersionFieldName {
+      request.headerFields[anthropicVersionFieldName] = Self.anthropicVersion
+    } else {
+      assertionFailure("\"anthropic-version\" is a valid header name and must never be nil.")
+    }
+    return try await next(request, body, baseURL)
+  }
+}

Sources/SyntaxKit/Core/Architecture.swift

@@ -0,0 +1,42 @@
+//
+//  Architecture.swift
+//  SyntaxKit
+//
+//  Created by Leo Dion.
+//  Copyright © 2026 BrightDigit.
+//
+//  Permission is hereby granted, free of charge, to any person
+//  obtaining a copy of this software and associated documentation
+//  files (the “Software”), to deal in the Software without
+//  restriction, including without limitation the rights to use,
+//  copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the
+//  Software is furnished to do so, subject to the following
+//  conditions:
+//
+//  The above copyright notice and this permission notice shall be
+//  included in all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+//  OTHER DEALINGS IN THE SOFTWARE.
+//
+
+/// CPU-architecture identifiers used in `arch(...)` checks.
+public enum Architecture: String, Sendable {
+  /// `arch(arm64)`
+  case arm64
+  /// `arch(x86_64)`
+  case x86 = "x86_64"
+  /// `arch(i386)`
+  case i386
+  /// `arch(arm)`
+  case arm
+  /// `arch(wasm32)`
+  case wasm32
+}

Sources/SyntaxKit/Core/Comparison.swift

@@ -0,0 +1,43 @@
+//
+//  Comparison.swift
+//  SyntaxKit
+//
+//  Created by Leo Dion.
+//  Copyright © 2026 BrightDigit.
+//
+//  Permission is hereby granted, free of charge, to any person
+//  obtaining a copy of this software and associated documentation
+//  files (the “Software”), to deal in the Software without
+//  restriction, including without limitation the rights to use,
+//  copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the
+//  Software is furnished to do so, subject to the following
+//  conditions:
+//
+//  The above copyright notice and this permission notice shall be
+//  included in all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+//  OTHER DEALINGS IN THE SOFTWARE.
+//
+
+/// The comparison operator used between a keyword and a version in a
+/// `swift(...)` / `compiler(...)` version check.
+public enum Comparison: String, Sendable {
+  /// `>=`
+  case greaterThanOrEqual = ">="
+  /// `>`
+  case greaterThan = ">"
+  /// `<=`
+  case lessThanOrEqual = "<="
+  /// `<`
+  case lessThan = "<"
+  /// `==`
+  case equal = "=="
+}

Sources/SyntaxKit/Core/OperatingSystem.swift

@@ -0,0 +1,54 @@
+//
+//  OperatingSystem.swift
+//  SyntaxKit
+//
+//  Created by Leo Dion.
+//  Copyright © 2026 BrightDigit.
+//
+//  Permission is hereby granted, free of charge, to any person
+//  obtaining a copy of this software and associated documentation
+//  files (the “Software”), to deal in the Software without
+//  restriction, including without limitation the rights to use,
+//  copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the
+//  Software is furnished to do so, subject to the following
+//  conditions:
+//
+//  The above copyright notice and this permission notice shall be
+//  included in all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+//  OTHER DEALINGS IN THE SOFTWARE.
+//
+
+/// Operating-system identifiers used in `os(...)` checks.
+public enum OperatingSystem: String, Sendable {
+  /// `os(iOS)`
+  case iOS
+  /// `os(macOS)`
+  case macOS
+  /// `os(tvOS)`
+  case tvOS
+  /// `os(watchOS)`
+  case watchOS
+  /// `os(visionOS)`
+  case visionOS
+  /// `os(anyAppleOS)` — matches any Apple operating system (Swift 6.4+).
+  case anyAppleOS
+  /// `os(Linux)`
+  case linux = "Linux"
+  /// `os(Windows)`
+  case windows = "Windows"
+  /// `os(FreeBSD)`
+  case freeBSD = "FreeBSD"
+  /// `os(Android)`
+  case android = "Android"
+  /// `os(WASI)`
+  case wasi = "WASI"
+}

Sources/SyntaxKit/Core/TargetEnvironment.swift

@@ -0,0 +1,36 @@
+//
+//  TargetEnvironment.swift
+//  SyntaxKit
+//
+//  Created by Leo Dion.
+//  Copyright © 2026 BrightDigit.
+//
+//  Permission is hereby granted, free of charge, to any person
+//  obtaining a copy of this software and associated documentation
+//  files (the “Software”), to deal in the Software without
+//  restriction, including without limitation the rights to use,
+//  copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the
+//  Software is furnished to do so, subject to the following
+//  conditions:
+//
+//  The above copyright notice and this permission notice shall be
+//  included in all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+//  OTHER DEALINGS IN THE SOFTWARE.
+//
+
+/// Target-environment identifiers used in `targetEnvironment(...)` checks.
+public enum TargetEnvironment: String, Sendable {
+  /// `targetEnvironment(simulator)`
+  case simulator
+  /// `targetEnvironment(macCatalyst)`
+  case macCatalyst
+}

Sources/SyntaxKit/Core/Version.swift

@@ -0,0 +1,64 @@
+//
+//  Version.swift
+//  SyntaxKit
+//
+//  Created by Leo Dion.
+//  Copyright © 2026 BrightDigit.
+//
+//  Permission is hereby granted, free of charge, to any person
+//  obtaining a copy of this software and associated documentation
+//  files (the “Software”), to deal in the Software without
+//  restriction, including without limitation the rights to use,
+//  copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the
+//  Software is furnished to do so, subject to the following
+//  conditions:
+//
+//  The above copyright notice and this permission notice shall be
+//  included in all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
+//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+//  OTHER DEALINGS IN THE SOFTWARE.
+//
+
+/// A `major.minor.patch` version, with optional minor and patch components.
+public struct Version: Sendable, CustomStringConvertible {
+  /// The major version component.
+  public let major: Int
+  /// The optional minor version component.
+  public let minor: Int?
+  /// The optional patch version component.
+  public let patch: Int?
+
+  /// The dotted string form, e.g. `5`, `5.9`, or `5.9.1`.
+  public var description: String {
+    var result = String(major)
+    if let minor = minor {
+      result += ".\(minor)"
+      if let patch = patch {
+        result += ".\(patch)"
+      }
+    }
+    return result
+  }
+
+  /// The dotted string form, e.g. `5`, `5.9`, or `5.9.1`.
+  internal var versionString: String { description }
+
+  /// Create a version from its components.
+  /// - Parameters:
+  ///   - major: The major version component.
+  ///   - minor: The optional minor version component.
+  ///   - patch: The optional patch version component.
+  public init(_ major: Int, _ minor: Int? = nil, _ patch: Int? = nil) {
+    self.major = major
+    self.minor = minor
+    self.patch = patch
+  }
+}