feat: Implement dedicated data fetchers and utilities for categories, products, and images, and add server compression.

src/utils/file-sync-utils.js

@@ -0,0 +1,134 @@
+import fs from 'fs/promises';
+import path from 'path';
+
+/**
+ * File synchronization utility functions
+ */
+
+/**
+ * Get existing IDs from files in a directory
+ * @param {string} dir - Directory path
+ * @param {Object} options - Configuration options
+ * @param {string} options.prefix - File prefix to filter (e.g., 'category_')
+ * @param {string} options.suffix - File suffix to filter (e.g., '.json')
+ * @param {RegExp} options.pattern - Custom regex pattern to extract ID
+ * @returns {Promise<number[]>} - Array of numeric IDs
+ */
+export async function getExistingIds(dir, options = {}) {
+    const { prefix = '', suffix = '', pattern = null } = options;
+
+    let existingFiles = [];
+    try {
+        existingFiles = await fs.readdir(dir);
+    } catch (err) {
+        // Directory might be empty or new
+        return [];
+    }
+
+    if (pattern) {
+        return existingFiles
+            .map(f => {
+                const match = f.match(pattern);
+                return match ? parseInt(match[1]) : null;
+            })
+            .filter(id => id !== null && !isNaN(id));
+    }
+
+    return existingFiles
+        .filter(f => {
+            if (prefix && !f.startsWith(prefix)) return false;
+            if (suffix && !f.endsWith(suffix)) return false;
+            return true;
+        })
+        .map(f => {
+            let id = f;
+            if (prefix) id = id.replace(prefix, '');
+            if (suffix) id = id.replace(suffix, '');
+            return parseInt(id);
+        })
+        .filter(id => !isNaN(id));
+}
+
+/**
+ * Delete obsolete files based on valid IDs
+ * @param {string} dir - Directory path
+ * @param {number[]} existingIds - IDs of existing files
+ * @param {Set<number>} validIds - Set of valid IDs to keep
+ * @param {Function} filenameFn - Function to generate filename from ID
+ * @returns {Promise<number>} - Number of files deleted
+ */
+export async function deleteObsoleteFiles(dir, existingIds, validIds, filenameFn) {
+    const toDelete = existingIds.filter(id => !validIds.has(id));
+
+    for (const id of toDelete) {
+        const filePath = path.join(dir, filenameFn(id));
+        await fs.unlink(filePath);
+    }
+
+    if (toDelete.length > 0) {
+        console.log(`🗑️  Deleted ${toDelete.length} obsolete files.`);
+    }
+
+    return toDelete.length;
+}
+
+/**
+ * Write JSON to file only if content has changed
+ * @param {string} filePath - Full path to file
+ * @param {*} data - Data to write (will be JSON.stringify'd)
+ * @param {number} indent - JSON indentation (default: 2)
+ * @returns {Promise<boolean>} - True if file was written, false if unchanged
+ */
+export async function writeJsonIfChanged(filePath, data, indent = 2) {
+    const newContent = JSON.stringify(data, null, indent);
+
+    let oldContent = '';
+    try {
+        oldContent = await fs.readFile(filePath, 'utf-8');
+    } catch (e) {
+        // File doesn't exist yet
+    }
+
+    if (oldContent !== newContent) {
+        await fs.writeFile(filePath, newContent);
+        return true;
+    }
+
+    return false;
+}
+
+/**
+ * Ensure directory exists, create if it doesn't
+ * @param {string} dir - Directory path
+ * @returns {Promise<void>}
+ */
+export async function ensureDir(dir) {
+    await fs.mkdir(dir, { recursive: true });
+}
+
+/**
+ * Read JSON file safely
+ * @param {string} filePath - Full path to file
+ * @returns {Promise<*|null>} - Parsed JSON or null if file doesn't exist
+ */
+export async function readJsonFile(filePath) {
+    try {
+        const content = await fs.readFile(filePath, 'utf-8');
+        return JSON.parse(content);
+    } catch (err) {
+        return null;
+    }
+}
+
+/**
+ * Read text file safely
+ * @param {string} filePath - Full path to file
+ * @returns {Promise<string|null>} - File content or null if file doesn't exist
+ */
+export async function readTextFile(filePath) {
+    try {
+        return await fs.readFile(filePath, 'utf-8');
+    } catch (err) {
+        return null;
+    }
+}