feat: add sharp-backed image rendering

apps/api/src/infrastructure/images/sharp-image-renderer.js

@@ -0,0 +1,21 @@
+import sharp from 'sharp';
+
+export function createSharpImageRenderer() {
+  return async function renderDerivative({ data, maxWidth }) {
+    if (!Buffer.isBuffer(data)) {
+      throw new TypeError('Image data must be provided as a Buffer.');
+    }
+
+    if (!Number.isInteger(maxWidth) || maxWidth <= 0) {
+      throw new TypeError('maxWidth must be a positive integer.');
+    }
+
+    const image = sharp(data);
+    const metadata = await image.metadata();
+
+    const targetWidth = metadata.width && metadata.width > maxWidth ? maxWidth : metadata.width ?? maxWidth;
+    const resized = targetWidth === metadata.width ? image : image.resize({ width: targetWidth, withoutEnlargement: true });
+
+    return resized.webp().toBuffer();
+  };
+}

apps/api/tests/application/image-derivative-processor.test.js

@@ -2,6 +2,7 @@ import assert from 'node:assert/strict';
 import test from 'node:test';
 
 import { createImageDerivativeProcessor } from '../../src/infrastructure/images/image-derivative-processor.js';
+import { createSharpImageRenderer } from '../../src/infrastructure/images/sharp-image-renderer.js';
 
 test('renders and stores thumbnail, medium, and large derivatives in order', async () => {
   const renderedWidths = [];
@@ -36,4 +37,17 @@ test('requires a renderer implementation', () => {
     () => createImageDerivativeProcessor({ imageStorage: {} }),
     /renderer is required/,
   );
+});
+
+test('creates a sharp-backed WebP renderer that resizes to the requested maximum width', async () => {
+  const renderer = createSharpImageRenderer();
+  const data = Buffer.from(
+    '<svg xmlns="http://www.w3.org/2000/svg" width="1024" height="1024" viewBox="0 0 1024 1024"><rect width="1024" height="1024" fill="#ff0000"/></svg>',
+  );
+  const output = await renderer({ data, maxWidth: 320 });
+
+  assert.ok(output instanceof Buffer);
+  assert.ok(output.length > 0);
+  assert.equal(output.subarray(0, 4).toString('ascii'), 'RIFF');
+  assert.equal(output.subarray(8, 12).toString('ascii'), 'WEBP');
 });