MOIDVK

import { spawn } from 'child_process'; import { writeFile, unlink, readFile } from 'fs/promises'; import { tmpdir } from 'os'; import { join } from 'path'; import { randomBytes } from 'crypto'; import { validatePythonCode, sanitizePythonFilename, detectPythonVersion } from '../utils/python-validation.js'; import { withTimeout, FORMAT_TIMEOUT_MS } from '../utils/timeout.js'; /** * Tool definition for python_formatter */ export const pythonFormatterTool = { name: 'python_formatter', description: 'Formats Python code using Black - the uncompromising Python code formatter. Ensures consistent code style across your Python projects.', inputSchema: { type: 'object', properties: { code: { type: 'string', description: 'The Python code to format (max 100KB)', }, filename: { type: 'string', description: 'Optional filename for context (e.g., \'main.py\')', }, check: { type: 'boolean', description: 'If true, only checks if formatting is needed without returning formatted code', default: false, }, pythonVersion: { type: 'string', description: 'Python version (auto-detected if not specified)', enum: ['2', '3'], }, // Style options lineLength: { type: 'number', description: 'Maximum line length', default: 88, minimum: 50, maximum: 200, }, skipStringNormalization: { type: 'boolean', description: 'Skip string quote normalization', default: false, }, skipMagicTrailingComma: { type: 'boolean', description: 'Skip magic trailing comma behavior', default: false, }, previewMode: { type: 'boolean', description: 'Enable preview mode for experimental features', default: false, }, }, required: ['code'], }, }; /** * Runs Black on Python code * @param {string} code - The Python code to format * @param {Object} options - Formatting options * @returns {Promise<Object>} Black output */ async function runBlack(code, options) { // Create a temporary file const tempFile = join(tmpdir(), `python_fmt_${randomBytes(8).toString('hex')}.py`); try { // Write code to temporary file await writeFile(tempFile, code, 'utf8'); // Build black arguments const args = [tempFile]; if (options.check) { args.push('--check'); args.push('--diff'); } // Add line length args.push('--line-length', options.lineLength.toString()); // Add target version if (options.pythonVersion === '2') { args.push('--target-version', 'py27'); } else { args.push('--target-version', 'py310'); } // Add style options if (options.skipStringNormalization) { args.push('--skip-string-normalization'); } if (options.skipMagicTrailingComma) { args.push('--skip-magic-trailing-comma'); } if (options.previewMode) { args.push('--preview'); } // Always output diff for comparison if (!options.check) { args.push('--quiet'); } return new Promise((resolve, reject) => { const black = spawn('black', args); let stdout = ''; let stderr = ''; black.stdout.on('data', (data) => { stdout += data.toString(); }); black.stderr.on('data', (data) => { stderr += data.toString(); }); black.on('close', async (exitCode) => { try { // Read the potentially formatted file let formattedCode = code; if (!options.check && exitCode === 0) { formattedCode = await readFile(tempFile, 'utf8'); } resolve({ stdout, stderr, exitCode, formattedCode, changed: exitCode === 1 || formattedCode !== code, }); } catch (error) { resolve({ stdout, stderr, exitCode }); } }); black.on('error', (error) => { reject(error); }); }); } finally { // Clean up try { await unlink(tempFile); } catch (e) { // Ignore cleanup errors } } } /** * Handles the python_formatter tool call * @param {Object} args - Tool arguments * @returns {Object} MCP response */ export async function handlePythonFormatter(args) { const { code, filename, check = false, pythonVersion, lineLength = 88, skipStringNormalization = false, skipMagicTrailingComma = false, previewMode = false, } = args.params || args; // Validate input const validation = validatePythonCode(code); if (!validation.valid) { return validation.error; } const safeFilename = sanitizePythonFilename(filename); const detectedVersion = pythonVersion || detectPythonVersion(code); try { // Check if black is available try { await withTimeout( new Promise((resolve, reject) => { spawn('black', ['--version']).on('close', code => { code === 0 ? resolve() : reject(new Error('Black not found')); }); }), 5000, 'Black check' ); } catch (error) { return { content: [{ type: 'text', text: '❌ Error: Black is not installed.\n\nInstall with: pip install black', }], }; } // Format options const options = { check, pythonVersion: detectedVersion, lineLength, skipStringNormalization, skipMagicTrailingComma, previewMode, }; // Run Black const formatPromise = runBlack(code, options); const result = await withTimeout(formatPromise, FORMAT_TIMEOUT_MS, 'Formatting'); if (check) { // Check mode - report if formatting is needed const needsFormatting = result.exitCode === 1; let output = '🐍 Python Code Formatting Check (Black):\n\n'; if (needsFormatting) { output += '⚠️ Code needs formatting. Run without \'check\' flag to format.\n\n'; if (result.stdout) { output += 'Diff preview:\n'; output += '```diff\n'; output += result.stdout; output += '```\n'; } } else { output += '✅ Code is already properly formatted according to Black standards.'; } return { content: [{ type: 'text', text: output, }], }; } // Format mode if (result.exitCode !== 0 && result.exitCode !== 1) { // Black failed let errorMessage = 'Failed to format code.'; if (result.stderr.includes('error:')) { const errorMatch = result.stderr.match(/error:\s*(.+)/); if (errorMatch) { errorMessage = `Syntax error: ${errorMatch[1]}`; } } return { content: [{ type: 'text', text: `❌ Error: ${errorMessage}\n\nPlease ensure the code is valid Python syntax.`, }], }; } const formatted = result.formattedCode || code; const changed = result.changed; let output = '🎨 Python Code Formatting Results (Black):\n\n'; if (!changed) { output += '✅ Code is already properly formatted according to Black standards.\n'; } else { output += '✅ Code formatted successfully!\n\n'; output += 'Formatting settings:\n'; output += ` Python version: ${detectedVersion}\n`; output += ` Line length: ${lineLength}\n`; output += ` String normalization: ${!skipStringNormalization}\n`; output += ` Magic trailing comma: ${!skipMagicTrailingComma}\n`; if (previewMode) { output += ' Preview mode: enabled\n'; } output += '\nFormatted code:\n'; output += '```python\n'; output += formatted; output += '```\n'; } output += '\n💡 Black enforces:\n'; output += '- Consistent indentation (4 spaces)\n'; output += '- Proper spacing around operators\n'; output += '- Consistent quote usage\n'; output += '- PEP 8 compliance with pragmatic choices'; return { content: [{ type: 'text', text: output, }], }; } catch (error) { console.error('Error formatting Python code:', error); let errorMessage = 'An error occurred while formatting the code.'; if (error.message === 'Formatting timeout exceeded') { errorMessage = 'Formatting timed out. The code might be too complex.'; } return { content: [{ type: 'text', text: `❌ Error: ${errorMessage}\n\nPlease ensure Black is installed and the code is valid.`, }], }; } }