BetterMCPFileServer

import fs from "fs/promises"; // Helper function to normalize line endings export function normalizeLineEndings(text: string): string { return text.replace(/\r\n/g, '\n'); } // Helper function to create unified diff export function createUnifiedDiff(oldText: string, newText: string, filePath: string): string { const oldLines = oldText.split('\n'); const newLines = newText.split('\n'); let output = `--- ${filePath}\n+++ ${filePath}\n`; let lineNumber = 1; let inDiffBlock = false; let diffBlockStart = 0; let diffLines: string[] = []; for (let i = 0; i < Math.max(oldLines.length, newLines.length); i++) { const oldLine = i < oldLines.length ? oldLines[i] : null; const newLine = i < newLines.length ? newLines[i] : null; if (oldLine !== newLine) { if (!inDiffBlock) { inDiffBlock = true; diffBlockStart = lineNumber; // Add context lines before diff (up to 3) const contextStart = Math.max(0, i - 3); for (let j = contextStart; j < i; j++) { if (j < oldLines.length) { diffLines.push(` ${oldLines[j]}`); } } } if (oldLine !== null && newLine !== null) { // Changed line diffLines.push(`-${oldLine}`); diffLines.push(`+${newLine}`); } else if (oldLine !== null) { // Removed line diffLines.push(`-${oldLine}`); } else if (newLine !== null) { // Added line diffLines.push(`+${newLine}`); } } else if (inDiffBlock) { // Add context lines after diff (up to 3) diffLines.push(` ${oldLine}`); if (diffLines.length >= 6 || i === Math.max(oldLines.length, newLines.length) - 1) { // Output the diff block const contextLines = Math.min(3, diffLines.filter(line => line.startsWith(' ')).length); const changedLines = diffLines.length - contextLines; output += `@@ -${diffBlockStart},${changedLines} +${diffBlockStart},${changedLines} @@\n`; output += diffLines.join('\n') + '\n'; inDiffBlock = false; diffLines = []; } } lineNumber++; } // Output any remaining diff block if (inDiffBlock && diffLines.length > 0) { const contextLines = Math.min(3, diffLines.filter(line => line.startsWith(' ')).length); const changedLines = diffLines.length - contextLines; output += `@@ -${diffBlockStart},${changedLines} +${diffBlockStart},${changedLines} @@\n`; output += diffLines.join('\n') + '\n'; } return output; } // Function to apply edits to a file export async function applyFileEdits( filePath: string, edits: Array<{oldText: string, newText: string}>, dryRun = false ): Promise<string> { // Read file content and normalize line endings const content = normalizeLineEndings(await fs.readFile(filePath, 'utf-8')); // Apply edits sequentially let modifiedContent = content; for (const edit of edits) { const normalizedOld = normalizeLineEndings(edit.oldText); const normalizedNew = normalizeLineEndings(edit.newText); // If exact match exists, use it if (modifiedContent.includes(normalizedOld)) { modifiedContent = modifiedContent.replace(normalizedOld, normalizedNew); continue; } // Otherwise, try line-by-line matching with flexibility for whitespace const oldLines = normalizedOld.split('\n'); const contentLines = modifiedContent.split('\n'); let matchFound = false; for (let i = 0; i <= contentLines.length - oldLines.length; i++) { const potentialMatch = contentLines.slice(i, i + oldLines.length); // Compare lines with normalized whitespace const isMatch = oldLines.every((oldLine, j) => { const contentLine = potentialMatch[j]; return oldLine.trim() === contentLine.trim(); }); if (isMatch) { // Preserve original indentation of first line const originalIndent = contentLines[i].match(/^\s*/)?.[0] || ''; const newLines = normalizedNew.split('\n').map((line, j) => { if (j === 0) return originalIndent + line.trimStart(); // For subsequent lines, try to preserve relative indentation const oldIndent = oldLines[j]?.match(/^\s*/)?.[0] || ''; const newIndent = line.match(/^\s*/)?.[0] || ''; if (oldIndent && newIndent) { const relativeIndent = newIndent.length - oldIndent.length; return originalIndent + ' '.repeat(Math.max(0, relativeIndent)) + line.trimStart(); } return line; }); contentLines.splice(i, oldLines.length, ...newLines); modifiedContent = contentLines.join('\n'); matchFound = true; break; } } if (!matchFound) { throw new Error(`Could not find exact match for edit:\n${edit.oldText}`); } } // Create unified diff const diff = createUnifiedDiff(content, modifiedContent, filePath); // Format diff with appropriate number of backticks let numBackticks = 3; while (diff.includes('`'.repeat(numBackticks))) { numBackticks++; } const formattedDiff = `${'`'.repeat(numBackticks)}diff\n${diff}${'`'.repeat(numBackticks)}\n\n`; if (!dryRun) { await fs.writeFile(filePath, modifiedContent, 'utf-8'); } return formattedDiff; }