Allow remark plugins to affect getImage call for .md files

.changeset/calm-socks-shake.md

@@ -0,0 +1,6 @@
+---
+"@astrojs/markdown-remark": minor
+"astro": minor
+---
+
+Allows remark plugins to pass options specifying how images in `.md` files will be optimized

packages/astro/src/vite-plugin-markdown/images.ts

@@ -2,33 +2,60 @@ export type MarkdownImagePath = { raw: string; resolved: string; safeName: strin
 
 export function getMarkdownCodeForImages(imagePaths: MarkdownImagePath[], html: string) {
 	return `
-		import { getImage } from "astro:assets";
-		${imagePaths
-			.map((entry) => `import Astro__${entry.safeName} from ${JSON.stringify(entry.raw)};`)
-			.join('\n')}
+			import { getImage } from "astro:assets";
+			${imagePaths
+				.map((entry) => `import Astro__${entry.safeName} from ${JSON.stringify(entry.raw)};`)
+				.join('\n')}
 
-		const images = async function() {
-			return {
-				${imagePaths
-					.map((entry) => `"${entry.raw}": await getImage({src: Astro__${entry.safeName}})`)
-					.join(',\n')}
-				}
-			}
+			const images = async function(html) {
+					const imageSources = {};
+					${imagePaths
+						.map((entry) => {
+							const rawUrl = JSON.stringify(entry.raw);
+							return `{
+											const regex = new RegExp('__ASTRO_IMAGE_="([^"]*' + ${rawUrl} + '[^"]*)"', 'g');
+											let match;
+											let occurrenceCounter = 0;
+											while ((match = regex.exec(html)) !== null) {
+													const matchKey = ${rawUrl} + '_' + occurrenceCounter;
+													const imageProps = JSON.parse(match[1].replace(/"/g, '"'));
+													const { src, ...props } = imageProps;
+
+													imageSources[matchKey] = await getImage({src: Astro__${entry.safeName}, ...props});
+													occurrenceCounter++;
+											}
+									}`;
+						})
+						.join('\n')}
+					return imageSources;
+			};
 
 			async function updateImageReferences(html) {
-				return images().then((images) => {
-					return html.replaceAll(/__ASTRO_IMAGE_="([^"]+)"/gm, (full, imagePath) =>
-					spreadAttributes({
-						src: images[imagePath].src,
-						...images[imagePath].attributes,
-					})
-					);
+				return images(html).then((imageSources) => {
+						return html.replaceAll(/__ASTRO_IMAGE_="([^"]+)"/gm, (full, imagePath) => {
+								const decodedImagePath = JSON.parse(imagePath.replace(/"/g, '"'));
+
+								// Use the 'index' property for each image occurrence
+								const srcKey = decodedImagePath.src + '_' + decodedImagePath.index;
+
+								if (imageSources[srcKey].srcSet && imageSources[srcKey].srcSet.values.length > 0) {
+										imageSources[srcKey].attributes.srcset = imageSources[srcKey].srcSet.attribute;
+								}
+
+								const { index, ...attributesWithoutIndex } = imageSources[srcKey].attributes;
+
+								return spreadAttributes({
+										src: imageSources[srcKey].src,
+										...attributesWithoutIndex,
+								});
+						});
 				});
-			}
+		}
+
 
-			// NOTE: This causes a top-level await to appear in the user's code, which can break very easily due to a Rollup
-			// bug and certain adapters not supporting it correctly. See: https://github.com/rollup/rollup/issues/4708
-			// Tread carefully!
+		// NOTE: This causes a top-level await to appear in the user's code, which can break very easily due to a Rollup
+	  // bug and certain adapters not supporting it correctly. See: https://github.com/rollup/rollup/issues/4708
+	  // Tread carefully!
 			const html = await updateImageReferences(${JSON.stringify(html)});
-		`;
+	`;
 }

packages/astro/test/core-image-remark-imgattr.test.js

@@ -0,0 +1,60 @@
+import { expect } from 'chai';
+import * as cheerio from 'cheerio';
+import { Writable } from 'node:stream';
+
+import { Logger } from '../dist/core/logger/core.js';
+import { loadFixture } from './test-utils.js';
+
+describe('astro:image', () => {
+	/** @type {import('./test-utils').Fixture} */
+	let fixture;
+
+	describe('dev', () => {
+		/** @type {import('./test-utils').DevServer} */
+		let devServer;
+		/** @type {Array<{ type: any, level: 'error', message: string; }>} */
+		let logs = [];
+
+		before(async () => {
+			fixture = await loadFixture({
+				root: './fixtures/core-image-remark-imgattr/',
+			});
+
+			devServer = await fixture.startDevServer({
+				logger: new Logger({
+					level: 'error',
+					dest: new Writable({
+						objectMode: true,
+						write(event, _, callback) {
+							logs.push(event);
+							callback();
+						},
+					}),
+				}),
+			});
+		});
+
+		after(async () => {
+			await devServer.stop();
+		});
+
+		describe('Test image attributes can be added by remark plugins', () => {
+			let $;
+			before(async () => {
+				let res = await fixture.fetch('/');
+				let html = await res.text();
+				$ = cheerio.load(html);
+			});
+
+			it('Image has eager loading meaning getImage passed props it doesnt use through it', async () => {
+				let $img = $('img');
+				expect($img.attr('loading')).to.equal('eager');
+			});
+
+			it('Image src contains w=50 meaning getImage correctly used props added through the remark plugin', async () => {
+				let $img = $('img');
+				expect(new URL($img.attr('src'), 'http://example.com').searchParams.get('w')).to.equal('50');
+			});
+		});
+	});
+});

packages/astro/test/fixtures/core-image-remark-imgattr/astro.config.mjs

@@ -0,0 +1,9 @@
+import { defineConfig } from 'astro/config';
+import plugin from "./remarkPlugin"
+
+// https://astro.build/config
+export default defineConfig({
+	markdown: {
+		remarkPlugins:[plugin]
+	}
+});

packages/astro/test/fixtures/core-image-remark-imgattr/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@test/core-image-remark-imgattr",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*"
+  },
+  "scripts": {
+    "dev": "astro dev"
+  }
+}

packages/astro/test/fixtures/core-image-remark-imgattr/remarkPlugin.js

@@ -0,0 +1,20 @@
+export default function plugin() {
+	return transformer;
+
+	function transformer(tree) {
+		function traverse(node) {
+			if (node.type === "image") {
+				node.data = node.data || {};
+				node.data.hProperties = node.data.hProperties || {};
+				node.data.hProperties.loading = "eager";
+				node.data.hProperties.width = "50";
+			}
+
+			if (node.children) {
+				node.children.forEach(traverse);
+			}
+		}
+
+		traverse(tree);
+	}
+}

packages/astro/test/fixtures/core-image-remark-imgattr/src/pages/index.md

@@ -0,0 +1 @@
+![alt](../assets/penguin2.jpg)

packages/astro/test/fixtures/core-image-remark-imgattr/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "extends": "astro/tsconfigs/base",
+  "compilerOptions": {
+    "baseUrl": ".",
+  }
+}

packages/markdown/remark/src/rehype-images.ts

@@ -3,17 +3,28 @@ import type { MarkdownVFile } from './types.js';
 
 export function rehypeImages() {
 	return () =>
-		function (tree: any, file: MarkdownVFile) {
-			visit(tree, (node) => {
-				if (node.type !== 'element') return;
-				if (node.tagName !== 'img') return;
+			function (tree: any, file: MarkdownVFile) {
+					const imageOccurrenceMap = new Map();
 
-				if (node.properties?.src) {
-					if (file.data.imagePaths?.has(node.properties.src)) {
-						node.properties['__ASTRO_IMAGE_'] = node.properties.src;
-						delete node.properties.src;
-					}
-				}
-			});
-		};
+					visit(tree, (node) => {
+							if (node.type !== 'element') return;
+							if (node.tagName !== 'img') return;
+
+							if (node.properties?.src) {
+									if (file.data.imagePaths?.has(node.properties.src)) {
+											const { ...props } = node.properties;
+
+											// Initialize or increment occurrence count for this image
+											const index = imageOccurrenceMap.get(node.properties.src) || 0;
+											imageOccurrenceMap.set(node.properties.src, index + 1);
+
+											node.properties['__ASTRO_IMAGE_'] = JSON.stringify({ ...props, index });
+
+											Object.keys(props).forEach((prop) => {
+													delete node.properties[prop];
+											});
+									}
+							}
+					});
+			};
 }

packages/markdown/remark/test/remark-collect-images.test.js

@@ -2,32 +2,32 @@ import { createMarkdownProcessor } from '../dist/index.js';
 import chai from 'chai';
 
 describe('collect images', async () => {
-	const processor = await createMarkdownProcessor();
+    const processor = await createMarkdownProcessor();
 
-	it('should collect inline image paths', async () => {
-		const {
-			code,
-			metadata: { imagePaths },
-		} = await processor.render(`Hello ![inline image url](./img.png)`, {
-			fileURL: 'file.md',
-		});
+    it('should collect inline image paths', async () => {
+        const {
+            code,
+            metadata: { imagePaths },
+        } = await processor.render(`Hello ![inline image url](./img.png)`, {
+            fileURL: 'file.md',
+        });
 
-		chai
-			.expect(code)
-			.to.equal('<p>Hello <img alt="inline image url" __ASTRO_IMAGE_="./img.png"></p>');
+        chai
+            .expect(code)
+            .to.equal('<p>Hello <img __ASTRO_IMAGE_="{&#x22;src&#x22;:&#x22;./img.png&#x22;,&#x22;alt&#x22;:&#x22;inline image url&#x22;,&#x22;index&#x22;:0}"></p>');
 
-		chai.expect(Array.from(imagePaths)).to.deep.equal(['./img.png']);
-	});
+        chai.expect(Array.from(imagePaths)).to.deep.equal(['./img.png']);
+    });
 
-	it('should add image paths from definition', async () => {
-		const {
-			code,
-			metadata: { imagePaths },
-		} = await processor.render(`Hello ![image ref][img-ref]\n\n[img-ref]: ./img.webp`, {
-			fileURL: 'file.md',
-		});
+    it('should add image paths from definition', async () => {
+        const {
+            code,
+            metadata: { imagePaths },
+        } = await processor.render(`Hello ![image ref][img-ref]\n\n[img-ref]: ./img.webp`, {
+            fileURL: 'file.md',
+        });
 
-		chai.expect(code).to.equal('<p>Hello <img alt="image ref" __ASTRO_IMAGE_="./img.webp"></p>');
-		chai.expect(Array.from(imagePaths)).to.deep.equal(['./img.webp']);
-	});
+        chai.expect(code).to.equal('<p>Hello <img __ASTRO_IMAGE_="{&#x22;src&#x22;:&#x22;./img.webp&#x22;,&#x22;alt&#x22;:&#x22;image ref&#x22;,&#x22;index&#x22;:0}"></p>');
+        chai.expect(Array.from(imagePaths)).to.deep.equal(['./img.webp']);
+    });
 });