Expo Docs MCP Server

import { execFile } from 'node:child_process'; import { promisify } from 'node:util'; import { mkdtemp, rm, readdir, readFile } from 'node:fs/promises'; import { tmpdir } from 'node:os'; import { join, relative } from 'node:path'; import { existsSync } from 'node:fs'; const execFileAsync = promisify(execFile); export interface GitFile { path: string; content: string; relativePath: string; } export class GitDownloader { private verbose: boolean; constructor(verbose = false) { this.verbose = verbose; } /** * Get the appropriate branch/ref for a given version */ private getVersionRef(version: string): string { if (version === 'latest') { return 'main'; } // For versioned releases, try sdk-XX format first if (version.startsWith('v')) { const versionNumber = version.slice(1); return `sdk-${versionNumber}`; } return version; } /** * Download Expo docs using git sparse-checkout */ async downloadDocs(version: string): Promise<Map<string, GitFile>> { const ref = this.getVersionRef(version); const repoUrl = 'https://github.com/expo/expo.git'; // Create temporary directory const tempDir = await mkdtemp(join(tmpdir(), 'expo-git-')); if (this.verbose) { console.log(`📁 Using temporary git directory: ${tempDir}`); } try { // Initialize git repository await execFileAsync('git', ['init'], { cwd: tempDir }); // Add remote await execFileAsync('git', ['remote', 'add', 'origin', repoUrl], { cwd: tempDir }); // Enable sparse-checkout await execFileAsync('git', ['config', 'core.sparseCheckout', 'true'], { cwd: tempDir }); // Set sparse-checkout pattern const sparseCheckoutFile = join(tempDir, '.git', 'info', 'sparse-checkout'); await import('node:fs/promises').then(fs => fs.writeFile(sparseCheckoutFile, 'docs/pages/\n', 'utf-8') ); if (this.verbose) { console.log(`🔍 Fetching ${ref} branch with sparse-checkout for docs/pages/...`); } // Fetch and checkout the specific branch with depth=1 for efficiency try { await execFileAsync('git', ['fetch', '--depth=1', 'origin', ref], { cwd: tempDir }); await execFileAsync('git', ['checkout', ref], { cwd: tempDir }); } catch (error) { // If specific branch doesn't exist, try main if (version !== 'latest') { console.warn(`⚠️ Branch '${ref}' not found, trying main branch for version ${version}`); await execFileAsync('git', ['fetch', '--depth=1', 'origin', 'main'], { cwd: tempDir }); await execFileAsync('git', ['checkout', 'main'], { cwd: tempDir }); } else { throw error; } } // Read all MDX files from docs/pages const docsPath = join(tempDir, 'docs', 'pages'); if (!existsSync(docsPath)) { throw new Error(`docs/pages directory not found in repository for version ${version}`); } const mdxFiles = await this.findMdxFiles(docsPath); console.log(`✅ Found ${mdxFiles.length} MDX files in repository`); // Read file contents const results = new Map<string, GitFile>(); for (const filePath of mdxFiles) { try { const content = await readFile(filePath, 'utf-8'); const relativePath = relative(docsPath, filePath); results.set(relativePath, { path: filePath, content, relativePath, }); if (this.verbose) { console.log(`📄 Loaded: ${relativePath}`); } } catch (error) { console.warn(`⚠️ Failed to read ${filePath}:`, error); } } console.log(`📦 Successfully loaded ${results.size} MDX files`); return results; } finally { // Cleanup temporary directory try { await rm(tempDir, { recursive: true, force: true }); if (this.verbose) { console.log(`🧹 Cleaned up git directory: ${tempDir}`); } } catch (cleanupError) { console.warn('Warning: Failed to cleanup git directory:', cleanupError); } } } /** * Recursively find all .mdx files in a directory */ private async findMdxFiles(dir: string): Promise<string[]> { const mdxFiles: string[] = []; const processDirectory = async (currentDir: string): Promise<void> => { try { const entries = await readdir(currentDir, { withFileTypes: true }); for (const entry of entries) { const fullPath = join(currentDir, entry.name); if (entry.isDirectory()) { await processDirectory(fullPath); } else if (entry.isFile() && entry.name.endsWith('.mdx')) { mdxFiles.push(fullPath); } } } catch (error) { console.warn(`⚠️ Failed to read directory ${currentDir}:`, error); } }; await processDirectory(dir); return mdxFiles; } }