2.实现语言服务端

笔记软件在2023/4/6 14:01:06推送该笔记

Language Server

这个语言服务器的源码在/server中。比较重要的pacakge.json部分是

"dependencies": {
    "vscode-languageserver": "^6.1.1",
    "vscode-languageserver-textdocument": "^1.0.1"
}

下面是一个服务器的实现，提供了简单的纯文本管理——VS Code会向服务器发送一个文件的全部内容

import {
  createConnection,
  TextDocuments,
  Diagnostic,
  DiagnosticSeverity,
  ProposedFeatures,
  InitializeParams,
  DidChangeConfigurationNotification,
  CompletionItem,
  CompletionItemKind,
  TextDocumentPositionParams,
  TextDocumentSyncKind,
  InitializeResult
} from 'vscode-languageserver';

import { TextDocument } from 'vscode-languageserver-textdocument';

// 创建一个服务器连接。使用Node的IPC作为传输方式。
// 也包含所有的预览、建议等LSP特性
let connection = createConnection(ProposedFeatures.all);

// 创建一个简单的文本管理器。
// 文本管理器只支持全文本同步。
let documents: TextDocuments<TextDocument> = new TextDocuments(TextDocument);

let hasConfigurationCapability: boolean = false;
let hasWorkspaceFolderCapability: boolean = false;
let hasDiagnosticRelatedInformationCapability: boolean = false;

connection.onInitialize((params: InitializeParams) => {
    let capabilities = params.capabilities;

    // 客户端是否支持`workspace/configuration`请求?
    // 如果不是的话，降级到使用全局设置
    hasConfigurationCapability = !!(
      capabilities.workspace && !!capabilities.workspace.configuration
    );
    hasWorkspaceFolderCapability = !!(
        capabilities.workspace && !!capabilities.workspace.workspaceFolders
    );
    hasDiagnosticRelatedInformationCapability = !!(
        capabilities.textDocument &&
        capabilities.textDocument.publishDiagnostics &&
        capabilities.textDocument.publishDiagnostics.relatedInformation
    );

    const result: InitializeResult = {
        capabilities: {
            textDocumentSync: TextDocumentSyncKind.Incremental,
            // Tell the client that this server supports code completion.
            completionProvider: {
                resolveProvider: true
            }
        }
    };

    if (hasWorkspaceFolderCapability) {
        result.capabilities.workspace = {
            workspaceFolders: {
                supported: true
            }
        };
    }

    return result;
});

connection.onInitialized(() => {
    if (hasConfigurationCapability) {
        // 为所有配置Register for all configuration changes.
        connection.client.register(
            DidChangeConfigurationNotification.type,
            undefined
        );
    }
    if (hasWorkspaceFolderCapability) {
        connection.workspace.onDidChangeWorkspaceFolders(_event => {
            connection.console.log('Workspace folder change event received.');
        });
    }
});

// 配置示例
interface ExampleSettings {
    maxNumberOfProblems: number;
}

// 当客户端不支持`workspace/configuration`请求时，使用global settings
// 请注意，在这个例子中服务器使用的客户端并不是问题所在，而是这种情况还可能发生在其他客户端身上。
const defaultSettings: ExampleSettings = { maxNumberOfProblems: 1000 };
let globalSettings: ExampleSettings = defaultSettings;

// 对所有打开的文档配置进行缓存
let documentSettings: Map<string, Thenable<ExampleSettings>> = new Map();

connection.onDidChangeConfiguration(change => {
    if (hasConfigurationCapability) {
        // 重置所有已缓存的文档配置
        documentSettings.clear();
    } else {
        globalSettings = <ExampleSettings>(
            (change.settings.languageServerExample || defaultSettings)
        );
    }

    // 重新验证所有打开的文本文档
    documents.all().forEach(validateTextDocument);
});

function getDocumentSettings(resource: string): Thenable<ExampleSettings> {
    if (!hasConfigurationCapability) {
        return Promise.resolve(globalSettings);
    }
    let result = documentSettings.get(resource);
    if (!result) {
        result = connection.workspace.getConfiguration({
            scopeUri: resource,
            section: 'languageServerExample'
        });
        documentSettings.set(resource, result);
    }
    return result;
}

// 只对打开的文档保留设置
documents.onDidClose(e => {
    documentSettings.delete(e.document.uri);
});

// 文档的文本内容发生了改变。
// 这个事件在文档第一次打开或者内容变动时才会触发。
documents.onDidChangeContent(change => {
    validateTextDocument(change.document);
});

async function validateTextDocument(textDocument: TextDocument): Promise<void> {
    // 在这个简单的示例中，每次校验运行时我们都获取一次配置
    let settings = await getDocumentSettings(textDocument.uri);

    // 校验器如果检测到连续超过2个以上的大写字母则会报错
    let text = textDocument.getText();
    let pattern = /\b[A-Z]{2,}\b/g;
    let m: RegExpExecArray | null;

    let problems = 0;
    let diagnostics: Diagnostic[] = [];
    while ((m = pattern.exec(text)) && problems < settings.maxNumberOfProblems) {
        problems++;
        let diagnosic: Diagnostic = {
            severity: DiagnosticSeverity.Warning,
            range: {
                start: textDocument.positionAt(m.index),
                end: textDocument.positionAt(m.index + m[0].length)
            },
            message: `${m[0]} is all uppercase.`,
            source: 'ex'
        };
        if (hasDiagnosticRelatedInformationCapability) {
            diagnosic.relatedInformation = [
                {
                    location: {
                        uri: textDocument.uri,
                        range: Object.assign({}, diagnosic.range)
                    },
                    message: 'Spelling matters'
                },
                {
                    location: {
                        uri: textDocument.uri,
                        range: Object.assign({}, diagnosic.range)
                    },
                    message: 'Particularly for names'
                }
            ];
        }
        diagnostics.push(diagnosic);
    }
    // 将错误处理结果发送给VS Code
    connection.sendDiagnostics({ uri: textDocument.uri, diagnostics });
}

connection.onDidChangeWatchedFiles(_change => {
    // 监测VS Code中的文件变动
    connection.console.log('We received an file change event');
});

// 这个处理函数提供了初始补全项列表
connection.onCompletion(
    (_textDocumentPosition: TextDocumentPositionParams): CompletionItem[] => {
    // 传入的变量包含了文本请求代码补全的位置。
    // 在这个示例中我们忽略了这个信息，总是提供相同的补全选项。
    return [
        {
            label: 'TypeScript',
            kind: CompletionItemKind.Text,
            data: 1
        },
        {
            label: 'JavaScript',
            kind: CompletionItemKind.Text,
            data: 2
        }
        ];
    }
);

// 这个函数为补全列表的选中项提供了更多信息
connection.onCompletionResolve(
    (item: CompletionItem): CompletionItem => {
        if (item.data === 1) {
            item.detail = 'TypeScript details';
            item.documentation = 'TypeScript documentation';
        } else if (item.data === 2) {
            item.detail = 'JavaScript details';
            item.documentation = 'JavaScript documentation';
        }
        return item;
    }
);

// 让文档管理器监听文档的打开，变动和关闭事件。
documents.listen(connection);

// 连接后启动监听
connection.listen();