Add MCP server for AI-driven control of InjectionNext #129
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Add MCP server for AI-driven control of InjectionNext
- ControlServer: local TCP server (localhost:8919) that exposes app actions as JSON commands (watch project, enable devices, get status, etc.) - LogBuffer: ring buffer capturing injection logs, compilation errors, and file watcher activity for AI consumption - MCP server (Node.js): 13 tools exposing InjectionNext to AI agents via the Model Context Protocol (get_status, watch_project, get_logs, etc.) - Hook log() and InjectionServer.log/error into LogBuffer for real-time debug console access Made-with: Cursor
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,356 @@ | ||
| // | ||
| // ControlServer.swift | ||
| // InjectionNext | ||
| // | ||
| // Local TCP control server for MCP integration. | ||
| // Listens on localhost:8919 for JSON commands and | ||
| // maps them to existing AppDelegate actions. | ||
| // | ||
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| import Cocoa | ||
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| // MARK: - Log Buffer | ||
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| class LogBuffer { | ||
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| static let shared = LogBuffer() | ||
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| struct Entry { | ||
| let timestamp: TimeInterval | ||
| let message: String | ||
| let level: String | ||
| } | ||
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| private let lock = NSLock() | ||
| private var entries = [Entry]() | ||
| private let maxEntries = 2000 | ||
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| func append(_ message: String, level: String = "info") { | ||
| lock.lock() | ||
| defer { lock.unlock() } | ||
| entries.append(Entry( | ||
| timestamp: Date().timeIntervalSince1970, | ||
| message: message, | ||
| level: level | ||
| )) | ||
| if entries.count > maxEntries { | ||
| entries.removeFirst(entries.count - maxEntries) | ||
| } | ||
| } | ||
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| func get(since: TimeInterval = 0, limit: Int = 200) -> [[String: Any]] { | ||
| lock.lock() | ||
| defer { lock.unlock() } | ||
| let filtered = entries.filter { $0.timestamp > since } | ||
| let sliced = filtered.suffix(limit) | ||
| return sliced.map { | ||
| ["timestamp": $0.timestamp, "message": $0.message, "level": $0.level] | ||
| } | ||
| } | ||
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| func clear() { | ||
| lock.lock() | ||
| defer { lock.unlock() } | ||
| entries.removeAll() | ||
| } | ||
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| var count: Int { | ||
| lock.lock() | ||
| defer { lock.unlock() } | ||
| return entries.count | ||
| } | ||
| } | ||
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| // MARK: - Control Server | ||
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| class ControlServer { | ||
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| static let port: UInt16 = 8919 | ||
| static var shared: ControlServer? | ||
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| private var serverSocket: Int32 = -1 | ||
| private let queue = DispatchQueue(label: "ControlServer", attributes: .concurrent) | ||
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| static func start() { | ||
| guard shared == nil else { return } | ||
| shared = ControlServer() | ||
| shared?.listen() | ||
| } | ||
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| private func listen() { | ||
| queue.async { [weak self] in | ||
| guard let self = self else { return } | ||
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| self.serverSocket = socket(AF_INET, SOCK_STREAM, 0) | ||
| guard self.serverSocket >= 0 else { | ||
| NSLog("\(APP_PREFIX)ControlServer: socket() failed") | ||
| return | ||
| } | ||
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| var reuse: Int32 = 1 | ||
| setsockopt(self.serverSocket, SOL_SOCKET, SO_REUSEADDR, &reuse, socklen_t(MemoryLayout<Int32>.size)) | ||
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|
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There was a problem hiding this comment. This control port accepts arbitrary JSON commands from any local process without authentication/authorization. Even bound to 127.0.0.1, this allows other local apps to toggle injection, change Xcode paths, launch Xcode, etc. Consider an opt-in enable flag plus a shared secret (token) requirement per request, or using a Unix domain socket with filesystem permissions to restrict who can connect. |
||
| var addr = sockaddr_in() | ||
| addr.sin_len = UInt8(MemoryLayout<sockaddr_in>.size) | ||
| addr.sin_family = sa_family_t(AF_INET) | ||
| addr.sin_port = Self.port.bigEndian | ||
| addr.sin_addr.s_addr = inet_addr("127.0.0.1") | ||
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| let bindResult = withUnsafePointer(to: &addr) { | ||
| $0.withMemoryRebound(to: sockaddr.self, capacity: 1) { | ||
| bind(self.serverSocket, $0, socklen_t(MemoryLayout<sockaddr_in>.size)) | ||
| } | ||
| } | ||
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| guard bindResult == 0 else { | ||
| NSLog("\(APP_PREFIX)ControlServer: bind() failed on port \(Self.port): \(String(cString: strerror(errno)))") | ||
| close(self.serverSocket) | ||
| return | ||
| } | ||
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| guard Darwin.listen(self.serverSocket, 5) == 0 else { | ||
| NSLog("\(APP_PREFIX)ControlServer: listen() failed") | ||
| close(self.serverSocket) | ||
| return | ||
| } | ||
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| NSLog("\(APP_PREFIX)ControlServer: listening on localhost:\(Self.port)") | ||
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| while true { | ||
| var clientAddr = sockaddr_in() | ||
| var clientLen = socklen_t(MemoryLayout<sockaddr_in>.size) | ||
| let clientSocket = withUnsafeMutablePointer(to: &clientAddr) { | ||
| $0.withMemoryRebound(to: sockaddr.self, capacity: 1) { | ||
| accept(self.serverSocket, $0, &clientLen) | ||
| } | ||
| } | ||
| guard clientSocket >= 0 else { continue } | ||
| self.queue.async { | ||
| self.handleClient(clientSocket) | ||
| } | ||
| } | ||
| } | ||
| } | ||
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| private func handleClient(_ sock: Int32) { | ||
| defer { close(sock) } | ||
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| var data = Data() | ||
| var buf = [UInt8](repeating: 0, count: 4096) | ||
| while true { | ||
| let n = recv(sock, &buf, buf.count, 0) | ||
| guard n > 0 else { break } | ||
| data.append(contentsOf: buf[0..<n]) | ||
| if data.contains(UInt8(ascii: "\n")) { break } | ||
| } | ||
|
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There was a problem hiding this comment.
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| guard !data.isEmpty, | ||
| let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any], | ||
| let action = json["action"] as? String else { | ||
| sendResponse(sock, success: false, error: "Invalid JSON or missing 'action'") | ||
| return | ||
| } | ||
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| let result = executeAction(action, params: json) | ||
| sendResponse(sock, success: result.success, data: result.data, error: result.error) | ||
| } | ||
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| private func sendResponse(_ sock: Int32, success: Bool, data: [String: Any]? = nil, error: String? = nil) { | ||
| var response: [String: Any] = ["success": success] | ||
| if let error = error { response["error"] = error } | ||
| if let data = data { response["data"] = data } | ||
| guard let jsonData = try? JSONSerialization.data(withJSONObject: response), | ||
| let jsonStr = String(data: jsonData, encoding: .utf8) else { return } | ||
| let line = jsonStr + "\n" | ||
| _ = line.withCString { ptr in | ||
| send(sock, ptr, strlen(ptr), 0) | ||
| } | ||
| } | ||
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| struct ActionResult { | ||
| let success: Bool | ||
| let data: [String: Any]? | ||
| let error: String? | ||
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| static func ok(_ data: [String: Any]? = nil) -> ActionResult { | ||
| ActionResult(success: true, data: data, error: nil) | ||
| } | ||
| static func fail(_ error: String) -> ActionResult { | ||
| ActionResult(success: false, data: nil, error: error) | ||
| } | ||
| } | ||
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| private func executeAction(_ action: String, params: [String: Any]) -> ActionResult { | ||
| switch action { | ||
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| case "status": | ||
| return getStatus() | ||
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| case "watch_project": | ||
| guard let path = params["path"] as? String else { | ||
| return .fail("Missing 'path' parameter") | ||
| } | ||
| return watchProject(path: path) | ||
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| case "stop_watching": | ||
| return stopWatching() | ||
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| case "launch_xcode": | ||
| return launchXcode() | ||
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| case "intercept_compiler": | ||
| return interceptCompiler() | ||
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| case "enable_devices": | ||
| let enable = params["enable"] as? Bool ?? true | ||
| return enableDevices(enable: enable) | ||
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| case "unhide_symbols": | ||
| return unhideSymbols() | ||
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| case "get_last_error": | ||
| return getLastError() | ||
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| case "prepare_swiftui_source": | ||
| return prepareSwiftUISource() | ||
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| case "prepare_swiftui_project": | ||
| return prepareSwiftUIProject() | ||
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| case "set_xcode_path": | ||
| guard let path = params["path"] as? String else { | ||
| return .fail("Missing 'path' parameter") | ||
| } | ||
| return setXcodePath(path: path) | ||
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| case "get_logs": | ||
| let since = params["since"] as? TimeInterval ?? 0 | ||
| let limit = params["limit"] as? Int ?? 200 | ||
| return getLogs(since: since, limit: limit) | ||
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|
Comment on lines
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There was a problem hiding this comment.
|
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| case "clear_logs": | ||
| return clearLogs() | ||
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| default: | ||
| return .fail("Unknown action: \(action)") | ||
| } | ||
| } | ||
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| // MARK: - Actions | ||
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| private func getStatus() -> ActionResult { | ||
| var result = [String: Any]() | ||
| DispatchQueue.main.sync { | ||
| let delegate = AppDelegate.ui! | ||
| result["xcode_running"] = MonitorXcode.runningXcode != nil | ||
| result["xcode_path"] = Defaults.xcodePath | ||
| result["compiler_intercepted"] = delegate.updatePatchUnpatch() == .patched | ||
| result["devices_enabled"] = delegate.enableDevicesItem.state == .on | ||
| result["watching_directories"] = Array(AppDelegate.watchers.keys) | ||
| result["has_connected_client"] = InjectionServer.currentClient != nil | ||
| result["auto_restart_xcode"] = Defaults.xcodeRestart | ||
| result["last_error"] = NextCompiler.lastError | ||
| } | ||
| return .ok(result) | ||
| } | ||
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| private func watchProject(path: String) -> ActionResult { | ||
| guard FileManager.default.fileExists(atPath: path) else { | ||
| return .fail("Path does not exist: \(path)") | ||
| } | ||
| DispatchQueue.main.sync { | ||
| Reloader.xcodeDev = Defaults.xcodePath + "/Contents/Developer" | ||
| AppDelegate.ui.watch(path: path) | ||
| } | ||
| return .ok(["watching": path]) | ||
| } | ||
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| private func stopWatching() -> ActionResult { | ||
| DispatchQueue.main.sync { | ||
| AppDelegate.watchers.removeAll() | ||
| AppDelegate.lastWatched = nil | ||
| AppDelegate.ui.watchDirectoryItem.state = .off | ||
| } | ||
| return .ok() | ||
| } | ||
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| private func launchXcode() -> ActionResult { | ||
| DispatchQueue.main.sync { | ||
| if MonitorXcode.runningXcode == nil { | ||
| _ = MonitorXcode() | ||
| } | ||
| } | ||
| return .ok(["xcode_path": Defaults.xcodePath]) | ||
| } | ||
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| private func interceptCompiler() -> ActionResult { | ||
| var state = "" | ||
| DispatchQueue.main.sync { | ||
| let delegate = AppDelegate.ui! | ||
| let currentState = delegate.updatePatchUnpatch() | ||
| state = currentState == .patched ? "patched" : "unpatched" | ||
| } | ||
| return .ok(["compiler_state": state, | ||
| "note": "Use Xcode UI to toggle interception (requires user confirmation alert)"]) | ||
| } | ||
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| private func enableDevices(enable: Bool) -> ActionResult { | ||
| DispatchQueue.main.sync { | ||
| let delegate = AppDelegate.ui! | ||
| let currentlyEnabled = delegate.enableDevicesItem.state == .on | ||
| if enable != currentlyEnabled { | ||
| delegate.deviceEnable(delegate.enableDevicesItem) | ||
| } | ||
| } | ||
| return .ok(["devices_enabled": enable]) | ||
| } | ||
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| private func unhideSymbols() -> ActionResult { | ||
| Unhider.startUnhide() | ||
| return .ok() | ||
| } | ||
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| private func getLastError() -> ActionResult { | ||
| let error = NextCompiler.lastError ?? "No error." | ||
| return .ok(["error": error]) | ||
| } | ||
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| private func prepareSwiftUISource() -> ActionResult { | ||
| guard let lastSource = NextCompiler.lastSource else { | ||
| return .fail("No source file currently being edited") | ||
| } | ||
| DispatchQueue.main.sync { | ||
| AppDelegate.ui.prepareSwiftUI(source: lastSource) | ||
| } | ||
| return .ok(["source": lastSource]) | ||
| } | ||
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| private func prepareSwiftUIProject() -> ActionResult { | ||
| DispatchQueue.main.sync { | ||
| AppDelegate.ui.prepareProject(AppDelegate.ui.patchCompilerItem) | ||
| } | ||
| return .ok() | ||
| } | ||
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| private func setXcodePath(path: String) -> ActionResult { | ||
| guard FileManager.default.fileExists(atPath: path) else { | ||
| return .fail("Xcode not found at: \(path)") | ||
| } | ||
| DispatchQueue.main.sync { | ||
| Defaults.xcodeDefault = path | ||
| AppDelegate.ui.selectXcodeItem.toolTip = path | ||
| AppDelegate.ui.updatePatchUnpatch() | ||
| } | ||
| return .ok(["xcode_path": path]) | ||
| } | ||
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| private func getLogs(since: TimeInterval, limit: Int) -> ActionResult { | ||
| let logs = LogBuffer.shared.get(since: since, limit: min(limit, 500)) | ||
| return .ok(["logs": logs, "count": LogBuffer.shared.count]) | ||
| } | ||
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| private func clearLogs() -> ActionResult { | ||
| LogBuffer.shared.clear() | ||
| return .ok() | ||
| } | ||
| } | ||
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LogBufferprunes withremoveFirst(...)once over capacity. OnArraythis is O(n) due to element shifting, which can become noticeable with frequent logging. If the intent is a ring buffer, consider implementing a fixed-size circular buffer (head index + count) to keep appends O(1).