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在 Xcode 中实现 LSP Client 涉及多个步骤,包括设置 Xcode 项目、实现 LSP 通信、处理 LSP 请求和响应等。下面是一个简单的指南,帮助你在 Xcode 中实现 LSP Client。

1. 设置 Xcode 项目

首先,创建一个新的 macOS 应用程序项目。在 Xcode 中,选择 File > New > Project,然后选择 macOS 平台并选择 App 模板。

2. 添加依赖库

你将需要一些第三方库来帮助处理 JSON 和网络通信。你可以使用 Swift Package Manager (SPM) 添加这些依赖库。

  • SwiftJSON:处理 JSON 数据
  • Starscream:WebSocket 库,用于与 LSP 服务器进行通信

在你的 Package.swift 文件中添加以下内容:

// swift-tools-version:5.3
import PackageDescription

let package = Package(
    name: "LSPClient",
    dependencies: [
        .package(url: "https://github.com/SwiftyJSON/SwiftyJSON.git", from: "5.0.0"),
        .package(url: "https://github.com/daltoniam/Starscream.git", from: "4.0.0"),
    ],
    targets: [
        .target(
            name: "LSPClient",
            dependencies: ["SwiftyJSON", "Starscream"]),
        .testTarget(
            name: "LSPClientTests",
            dependencies: ["LSPClient"]),
    ]
)

3. 实现 LSP 通信

在项目中创建一个新的 Swift 文件,用于实现与 LSP 服务器的通信。

连接到 LSP 服务器

使用 Starscream 连接到 LSP 服务器:

import Foundation
import Starscream
import SwiftyJSON

class LSPClient: WebSocketDelegate {
    var socket: WebSocket!

    init() {
        var request = URLRequest(url: URL(string: "ws://localhost:8080")!)
        request.timeoutInterval = 5
        socket = WebSocket(request: request)
        socket.delegate = self
    }

    func connect() {
        socket.connect()
    }

    func websocketDidConnect(socket: WebSocketClient) {
        print("Connected to LSP server")
        sendInitializeRequest()
    }

    func websocketDidDisconnect(socket: WebSocketClient, error: Error?) {
        print("Disconnected from LSP server: \(String(describing: error))")
    }

    func websocketDidReceiveMessage(socket: WebSocketClient, text: String) {
        print("Received message: \(text)")
        handleResponse(text: text)
    }

    func websocketDidReceiveData(socket: WebSocketClient, data: Data) {
        print("Received data: \(data.count) bytes")
    }

    func sendInitializeRequest() {
        let params: [String: Any] = [
            "processId": ProcessInfo.processInfo.processIdentifier,
            "rootUri": "file:///\(NSHomeDirectory())",
            "capabilities": [:]
        ]
        let message: [String: Any] = [
            "jsonrpc": "2.0",
            "id": 1,
            "method": "initialize",
            "params": params
        ]
        sendMessage(message: message)
    }

    func sendMessage(message: [String: Any]) {
        if let jsonData = try? JSONSerialization.data(withJSONObject: message, options: []) {
            let jsonString = String(data: jsonData, encoding: .utf8)!
            socket.write(string: jsonString)
        }
    }

    func handleResponse(text: String) {
        if let data = text.data(using: .utf8) {
            let json = try? JSON(data: data)
            print("Response JSON: \(String(describing: json))")
        }
    }
}

4. 处理 LSP 请求和响应

LSPClient 类中添加处理 LSP 请求和响应的方法。例如,处理 textDocument/didOpentextDocument/completion 请求。

处理 textDocument/didOpen 请求

func sendDidOpenTextDocument(uri: String, languageId: String, version: Int, text: String) {
    let params: [String: Any] = [
        "textDocument": [
            "uri": uri,
            "languageId": languageId,
            "version": version,
            "text": text
        ]
    ]
    let message: [String: Any] = [
        "jsonrpc": "2.0",
        "method": "textDocument/didOpen",
        "params": params
    ]
    sendMessage(message: message)
}

处理 textDocument/completion 请求

func sendCompletionRequest(uri: String, position: [String: Int]) {
    let params: [String: Any] = [
        "textDocument": [
            "uri": uri
        ],
        "position": position
    ]
    let message: [String: Any] = [
        "jsonrpc": "2.0",
        "id": 2,
        "method": "textDocument/completion",
        "params": params
    ]
    sendMessage(message: message)
}

5. 测试 LSP Client

在你的应用中实例化 LSPClient 并测试其功能:

import Cocoa

@main
class AppDelegate: NSObject, NSApplicationDelegate {
    var lspClient: LSPClient!

    func applicationDidFinishLaunching(_ aNotification: Notification) {
        lspClient = LSPClient()
        lspClient.connect()

        // 示例:发送文本文档打开请求
        lspClient.sendDidOpenTextDocument(uri: "file:///path/to/file.swift", languageId: "swift", version: 1, text: "let a = 1")

        // 示例:发送代码补全请求
        lspClient.sendCompletionRequest(uri: "file:///path/to/file.swift", position: ["line": 0, "character": 4])
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        // 清理资源
    }
}

以上步骤只是一个基本示例。根据你的具体需求,你可能需要处理更多的 LSP 方法和响应,并实现更复杂的逻辑。通过这些步骤,你可以在 Xcode 中实现一个简单的 LSP Client,并与 LSP 服务器进行通信。

MacOS 上的开源实现:https://github.com/ChimeHQ/LanguageClient
https://github.com/ChimeHQ/LanguageServerProtocol
https://medium.com/@malintha1996/understanding-the-language-server-protocol-5c0ba3ac83d2