Flutter MCP Service

import axios from 'axios'; import * as cheerio from 'cheerio'; import { flutterAPIPatterns } from '../validators/apiPatterns.js'; const FLUTTER_DOCS_BASE = 'https://api.flutter.dev/flutter'; const FLUTTER_WIDGETS_CATALOG = 'https://docs.flutter.dev/ui/widgets'; export async function validateFlutterDocs(args) { const { code, widgetType } = args; const validationResults = { deprecatedAPIs: [], incorrectUsage: [], recommendations: [], documentationLinks: [], }; try { const usedWidgets = extractWidgets(code); const usedMethods = extractMethods(code); for (const widget of usedWidgets) { const widgetValidation = await validateWidget(widget, code); if (widgetValidation.issues.length > 0) { validationResults.incorrectUsage.push(...widgetValidation.issues); } if (widgetValidation.deprecated) { validationResults.deprecatedAPIs.push({ widget, replacement: widgetValidation.replacement, reason: widgetValidation.reason, }); } if (widgetValidation.docLink) { validationResults.documentationLinks.push({ widget, link: widgetValidation.docLink, }); } } const propertyValidation = validateProperties(code, usedWidgets); validationResults.incorrectUsage.push(...propertyValidation); const bestPractices = checkBestPractices(code, usedWidgets); validationResults.recommendations.push(...bestPractices); if (widgetType) { const specificValidation = await validateSpecificWidget(widgetType, code); validationResults.recommendations.push(...specificValidation); } return { content: [ { type: 'text', text: JSON.stringify({ validationResults, summary: generateValidationSummary(validationResults), score: calculateComplianceScore(validationResults), }, null, 2), }, ], }; } catch (error) { return { content: [ { type: 'text', text: `Error validating against Flutter documentation: ${error.message}`, }, ], }; } } function extractWidgets(code) { const widgetPattern = /\b([A-Z][a-zA-Z]*)\s*\(/g; const matches = [...code.matchAll(widgetPattern)]; const widgets = matches.map(match => match[1]); const flutterWidgets = [ 'Container', 'Row', 'Column', 'Stack', 'Scaffold', 'AppBar', 'Text', 'Image', 'Icon', 'IconButton', 'ElevatedButton', 'TextButton', 'ListView', 'GridView', 'SingleChildScrollView', 'CustomScrollView', 'AnimatedBuilder', 'AnimatedContainer', 'Hero', 'Transform', 'GestureDetector', 'InkWell', 'Draggable', 'DragTarget', ]; return widgets.filter(w => flutterWidgets.includes(w)); } function extractMethods(code) { const methodPattern = /\.(\w+)\s*\(/g; const matches = [...code.matchAll(methodPattern)]; return matches.map(match => match[1]); } async function validateWidget(widget, code) { const validation = { issues: [], deprecated: false, replacement: null, reason: null, docLink: `${FLUTTER_DOCS_BASE}/widgets/${widget}-class.html`, }; const deprecatedWidgets = { 'FlatButton': { replacement: 'TextButton', reason: 'Deprecated in Flutter 2.0' }, 'RaisedButton': { replacement: 'ElevatedButton', reason: 'Deprecated in Flutter 2.0' }, 'OutlineButton': { replacement: 'OutlinedButton', reason: 'Deprecated in Flutter 2.0' }, }; if (deprecatedWidgets[widget]) { validation.deprecated = true; validation.replacement = deprecatedWidgets[widget].replacement; validation.reason = deprecatedWidgets[widget].reason; } const widgetRules = getWidgetRules(widget); if (widgetRules) { for (const rule of widgetRules) { if (!rule.validate(code)) { validation.issues.push({ widget, issue: rule.message, severity: rule.severity, }); } } } return validation; } function getWidgetRules(widget) { const rules = { 'Container': [ { validate: (code) => { const containerMatch = code.match(/Container\s*\([^)]*\)/); if (containerMatch) { const hasChild = containerMatch[0].includes('child:'); const hasDecoration = containerMatch[0].includes('decoration:'); const hasColor = containerMatch[0].includes('color:'); return !(hasDecoration && hasColor); } return true; }, message: 'Cannot provide both color and decoration properties', severity: 'error', }, ], 'Column': [ { validate: (code) => { const columnMatch = code.match(/Column\s*\([^{]*{[^}]*}\s*\)/); if (columnMatch && columnMatch[0].includes('Expanded')) { return true; } if (columnMatch && columnMatch[0].includes('Flexible')) { return true; } return !code.includes('RenderFlex overflowed'); }, message: 'Consider using Expanded or Flexible for children that might overflow', severity: 'warning', }, ], 'ListView': [ { validate: (code) => { const listViewMatch = code.match(/ListView\s*\([^)]*\)/); if (listViewMatch) { return listViewMatch[0].includes('shrinkWrap: true') || !code.includes('Column') || code.includes('Expanded'); } return true; }, message: 'ListView inside Column requires shrinkWrap: true or wrap with Expanded', severity: 'error', }, ], }; return rules[widget] || null; } function validateProperties(code, widgets) { const issues = []; if (code.includes('setState') && !code.includes('mounted')) { issues.push({ property: 'setState', issue: 'Always check mounted before calling setState', severity: 'warning', suggestion: 'if (mounted) { setState(() { ... }); }', }); } if (code.includes('MediaQuery.of(context)') && !code.includes('MediaQuery.maybeOf')) { issues.push({ property: 'MediaQuery', issue: 'Consider using MediaQuery.maybeOf for safer null handling', severity: 'info', }); } return issues; } function checkBestPractices(code, widgets) { const recommendations = []; if (widgets.includes('Container') && !hasConstraints(code)) { recommendations.push({ type: 'best_practice', message: 'Container without constraints can expand infinitely', suggestion: 'Provide width/height or use constraints', }); } if (code.includes('Key(') && !code.includes('ValueKey') && !code.includes('UniqueKey')) { recommendations.push({ type: 'best_practice', message: 'Use specific Key types (ValueKey, UniqueKey, ObjectKey) instead of generic Key', }); } if (widgets.includes('Image') && !code.includes('errorBuilder')) { recommendations.push({ type: 'robustness', message: 'Add errorBuilder to Image widgets for better error handling', }); } return recommendations; } async function validateSpecificWidget(widgetType, code) { const recommendations = []; const widgetGuidelines = { 'Form': [ 'Use GlobalKey<FormState> for form validation', 'Implement proper validation for each TextFormField', 'Handle form submission with proper error states', ], 'AnimatedBuilder': [ 'Ensure animation controller is properly disposed', 'Use const constructors for child widgets that don\'t animate', 'Consider AnimatedWidget for simpler cases', ], 'StreamBuilder': [ 'Always handle all ConnectionState cases', 'Provide initialData when possible', 'Handle error states explicitly', ], }; if (widgetGuidelines[widgetType]) { widgetGuidelines[widgetType].forEach(guideline => { recommendations.push({ type: 'guideline', widget: widgetType, message: guideline, }); }); } return recommendations; } function hasConstraints(code) { const constraintProperties = ['width:', 'height:', 'constraints:']; return constraintProperties.some(prop => code.includes(prop)); } function generateValidationSummary(results) { return { totalIssues: results.incorrectUsage.length + results.deprecatedAPIs.length, criticalIssues: results.incorrectUsage.filter(i => i.severity === 'error').length, deprecatedAPIs: results.deprecatedAPIs.length, recommendations: results.recommendations.length, documentationAvailable: results.documentationLinks.length, }; } function calculateComplianceScore(results) { let score = 100; results.incorrectUsage.forEach(issue => { if (issue.severity === 'error') score -= 10; else if (issue.severity === 'warning') score -= 5; else score -= 2; }); score -= results.deprecatedAPIs.length * 15; return Math.max(0, score); }