MCP Code Analysis & Quality Server

// Copyright 2025 Chris Bunting // Brief: Language detection service for Static Analysis MCP Server // Scope: Automatically detects programming languages based on file extensions and content import { Language } from '@mcp-code-analysis/shared-types'; import { readFileSync, existsSync } from 'fs'; import { extname } from 'path'; export class LanguageDetector { private extensionMap: Map<string, Language> = new Map([ ['.js', Language.JAVASCRIPT], ['.jsx', Language.JAVASCRIPT], ['.mjs', Language.JAVASCRIPT], ['.ts', Language.TYPESCRIPT], ['.tsx', Language.TYPESCRIPT], ['.py', Language.PYTHON], ['.pyx', Language.PYTHON], ['.java', Language.JAVA], ['.c', Language.C], ['.h', Language.C], ['.cpp', Language.CPP], ['.cxx', Language.CPP], ['.cc', Language.CPP], ['.hpp', Language.CPP], ['.go', Language.GO], ['.rs', Language.RUST], ]); private shebangMap: Map<string, Language> = new Map([ ['#!/usr/bin/env node', Language.JAVASCRIPT], ['#!/usr/bin/env python', Language.PYTHON], ['#!/usr/bin/env python3', Language.PYTHON], ['#!/usr/bin/env java', Language.JAVA], ['#!/usr/bin/env go', Language.GO], ['#!/usr/bin/env rust', Language.RUST], ]); detectLanguage(filePath: string, content?: string): Language { const extension = extname(filePath).toLowerCase(); // First, try to detect by file extension if (this.extensionMap.has(extension)) { return this.extensionMap.get(extension)!; } // If content is provided, try to detect by shebang if (content) { const firstLine = content.split('\n')[0].trim(); if (firstLine.startsWith('#!')) { for (const [shebang, language] of this.shebangMap) { if (firstLine.includes(shebang.substring(2))) { return language; } } } // Additional content-based detection return this.detectByContent(content); } // If file exists, read its content for detection if (existsSync(filePath)) { try { const fileContent = readFileSync(filePath, 'utf-8'); return this.detectByContent(fileContent); } catch (error) { // If we can't read the file, fall back to extension-based detection return this.getDefaultLanguage(extension); } } return this.getDefaultLanguage(extension); } private detectByContent(content: string): Language { const lines = content.split('\n'); // Check for shebang const firstLine = lines[0].trim(); if (firstLine.startsWith('#!')) { for (const [shebang, language] of this.shebangMap) { if (firstLine.includes(shebang.substring(2))) { return language; } } } // Check for language-specific patterns const contentLower = content.toLowerCase(); // Python detection if (contentLower.includes('import ') || contentLower.includes('from ')) { const pythonImports = [ 'import os', 'import sys', 'import numpy', 'import pandas', 'from os import', 'from sys import', 'from numpy import' ]; if (pythonImports.some(imp => contentLower.includes(imp))) { return Language.PYTHON; } } // Java detection if (contentLower.includes('public class') || contentLower.includes('private class') || contentLower.includes('import java.')) { return Language.JAVA; } // TypeScript detection if (contentLower.includes(': ') && contentLower.includes('interface ') || contentLower.includes('type ') || contentLower.includes('enum ')) { return Language.TYPESCRIPT; } // JavaScript detection if (contentLower.includes('function ') || contentLower.includes('const ') || contentLower.includes('let ') || contentLower.includes('var ')) { return Language.JAVASCRIPT; } // Go detection if (contentLower.includes('package main') || contentLower.includes('func ') || contentLower.includes('import (')) { return Language.GO; } // Rust detection if (contentLower.includes('fn ') || contentLower.includes('let mut') || contentLower.includes('use std::')) { return Language.RUST; } // C/C++ detection if (contentLower.includes('#include <') || contentLower.includes('#include "') || contentLower.includes('int main') || contentLower.includes('void main')) { // Differentiate between C and C++ if (contentLower.includes('#include <iostream>') || contentLower.includes('using namespace') || contentLower.includes('std::') || contentLower.includes('class ')) { return Language.CPP; } return Language.C; } // Default fallback return Language.JAVASCRIPT; } private getDefaultLanguage(extension: string): Language { // Common fallbacks based on extension switch (extension) { case '.txt': case '.md': return Language.JAVASCRIPT; // Default for text files default: return Language.JAVASCRIPT; } } getSupportedLanguages(): Language[] { return Array.from(new Set(this.extensionMap.values())); } getSupportedExtensions(): string[] { return Array.from(this.extensionMap.keys()); } isLanguageSupported(language: Language): boolean { return this.getSupportedLanguages().includes(language); } addExtensionMapping(extension: string, language: Language): void { this.extensionMap.set(extension.toLowerCase(), language); } addShebangMapping(shebang: string, language: Language): void { this.shebangMap.set(shebang, language); } }