build 1

backend/src/services/image.ts

@@ -0,0 +1,91 @@
+import sharp from 'sharp';
+import fs from 'fs';
+import { absolutePath, ensureDir } from './storage.js';
+
+export interface ImageMeta {
+  width: number;
+  height: number;
+  mimeType: string;
+  size: number;
+}
+
+export async function extractMeta(filePath: string): Promise<ImageMeta> {
+  const abs = absolutePath(filePath);
+  const meta = await sharp(abs).metadata();
+  const stat = fs.statSync(abs);
+
+  const mimeMap: Record<string, string> = {
+    jpeg: 'image/jpeg',
+    png: 'image/png',
+    gif: 'image/gif',
+    webp: 'image/webp',
+  };
+
+  return {
+    width: meta.width ?? 0,
+    height: meta.height ?? 0,
+    mimeType: mimeMap[meta.format ?? ''] ?? 'image/jpeg',
+    size: stat.size,
+  };
+}
+
+export async function saveBuffer(buffer: Buffer, destRelPath: string): Promise<void> {
+  ensureDir(destRelPath);
+  const abs = absolutePath(destRelPath);
+  fs.writeFileSync(abs, buffer);
+}
+
+export interface ResizeOptions {
+  width?: number;
+  height?: number;
+  quality?: number;
+}
+
+export async function resizeImage(
+  srcRelPath: string,
+  destRelPath: string,
+  options: ResizeOptions
+): Promise<ImageMeta> {
+  const srcAbs = absolutePath(srcRelPath);
+  ensureDir(destRelPath);
+  const destAbs = absolutePath(destRelPath);
+
+  const src = await sharp(srcAbs).metadata();
+  const isGif = src.format === 'gif';
+
+  let pipeline = sharp(srcAbs, { animated: isGif });
+
+  if (options.width || options.height) {
+    pipeline = pipeline.resize({
+      width: options.width,
+      height: options.height,
+      fit: 'inside',
+      withoutEnlargement: true,
+    });
+  }
+
+  if (!isGif && options.quality) {
+    if (src.format === 'jpeg') pipeline = pipeline.jpeg({ quality: options.quality });
+    else if (src.format === 'png') pipeline = pipeline.png({ quality: options.quality });
+    else if (src.format === 'webp') pipeline = pipeline.webp({ quality: options.quality });
+  }
+
+  await pipeline.toFile(destAbs);
+
+  const resultMeta = await sharp(destAbs).metadata();
+  const stat = fs.statSync(destAbs);
+
+  const mimeMap: Record<string, string> = {
+    jpeg: 'image/jpeg',
+    png: 'image/png',
+    gif: 'image/gif',
+    webp: 'image/webp',
+  };
+
+  return {
+    width: resultMeta.width ?? 0,
+    height: resultMeta.height ?? 0,
+    mimeType: mimeMap[resultMeta.format ?? ''] ?? 'image/jpeg',
+    size: stat.size,
+  };
+}