Add validateOptions hook to Image Service API

.changeset/tidy-dryers-add.md

@@ -0,0 +1,6 @@
+---
+'astro': patch
+'@astrojs/markdown-remark': patch
+---
+
+Add a `validateOptions` hook to the Image Service API in order to set default options and validate the passed options

packages/astro/src/assets/internal.ts

@@ -27,6 +27,7 @@ export async function getConfiguredImageService(): Promise<ImageService> {
 }
 
 interface GetImageResult {
+	rawOptions: ImageTransform;
 	options: ImageTransform;
 	src: string;
 	attributes: Record<string, any>;
@@ -50,17 +51,21 @@ interface GetImageResult {
  */
 export async function getImage(options: ImageTransform): Promise<GetImageResult> {
 	const service = await getConfiguredImageService();
-	let imageURL = service.getURL(options);
+	const validatedOptions = service.validateOptions ? service.validateOptions(options) : options;
+
+	let imageURL = service.getURL(validatedOptions);
 
 	// In build and for local services, we need to collect the requested parameters so we can generate the final images
 	if (isLocalService(service) && globalThis.astroAsset.addStaticImage) {
-		imageURL = globalThis.astroAsset.addStaticImage(options);
+		imageURL = globalThis.astroAsset.addStaticImage(validatedOptions);
 	}
 
 	return {
-		options,
+		rawOptions: options,
+		options: validatedOptions,
 		src: imageURL,
-		attributes: service.getHTMLAttributes !== undefined ? service.getHTMLAttributes(options) : {},
+		attributes:
+			service.getHTMLAttributes !== undefined ? service.getHTMLAttributes(validatedOptions) : {},
 	};
 }
 

packages/astro/src/assets/services/service.ts

@@ -39,6 +39,15 @@ interface SharedServiceProps {
 	 * In most cases, you'll want to return directly what your user supplied you, minus the attributes that were used to generate the image.
 	 */
 	getHTMLAttributes?: (options: ImageTransform) => Record<string, any>;
+	/**
+	 * Validate and return the options passed by the user.
+	 *
+	 * This method is useful to present errors to users who have entered invalid options.
+	 * For instance, if they are missing a required property or have entered an invalid image format.
+	 *
+	 * This method should returns options, and can be used to set defaults (ex: a default output format to be used if the user didn't specify one.)
+	 */
+	validateOptions?: (options: ImageTransform) => ImageTransform;
 }
 
 export type ExternalImageService = SharedServiceProps;
@@ -69,7 +78,7 @@ export type BaseServiceTransform = {
 	src: string;
 	width?: number;
 	height?: number;
-	format?: string | null;
+	format: string;
 	quality?: string | null;
 };
 
@@ -94,6 +103,45 @@ export type BaseServiceTransform = {
  *
  */
 export const baseService: Omit<LocalImageService, 'transform'> = {
+	validateOptions(options) {
+		if (!isESMImportedImage(options.src)) {
+			// For remote images, width and height are explicitly required as we can't infer them from the file
+			let missingDimension: 'width' | 'height' | 'both' | undefined;
+			if (!options.width && !options.height) {
+				missingDimension = 'both';
+			} else if (!options.width && options.height) {
+				missingDimension = 'width';
+			} else if (options.width && !options.height) {
+				missingDimension = 'height';
+			}
+
+			if (missingDimension) {
+				throw new AstroError({
+					...AstroErrorData.MissingImageDimension,
+					message: AstroErrorData.MissingImageDimension.message(missingDimension, options.src),
+				});
+			}
+		} else {
+			if (!VALID_INPUT_FORMATS.includes(options.src.format as any)) {
+				throw new AstroError({
+					...AstroErrorData.UnsupportedImageFormat,
+					message: AstroErrorData.UnsupportedImageFormat.message(
+						options.src.format,
+						options.src.src,
+						VALID_INPUT_FORMATS
+					),
+				});
+			}
+		}
+
+		// If the user didn't specify a format, we'll default to `webp`. It offers the best ratio of compatibility / quality
+		// In the future, hopefully we can replace this with `avif`, alas, Edge. See https://caniuse.com/avif
+		if (!options.format) {
+			options.format = 'webp';
+		}
+
+		return options;
+	},
 	getHTMLAttributes(options) {
 		let targetWidth = options.width;
 		let targetHeight = options.height;
@@ -123,39 +171,11 @@ export const baseService: Omit<LocalImageService, 'transform'> = {
 		};
 	},
 	getURL(options: ImageTransform) {
+		// Both our currently available local services don't handle remote images, so we return the path as is.
 		if (!isESMImportedImage(options.src)) {
-			// For remote images, width and height are explicitly required as we can't infer them from the file
-			let missingDimension: 'width' | 'height' | 'both' | undefined;
-			if (!options.width && !options.height) {
-				missingDimension = 'both';
-			} else if (!options.width && options.height) {
-				missingDimension = 'width';
-			} else if (options.width && !options.height) {
-				missingDimension = 'height';
-			}
-
-			if (missingDimension) {
-				throw new AstroError({
-					...AstroErrorData.MissingImageDimension,
-					message: AstroErrorData.MissingImageDimension.message(missingDimension, options.src),
-				});
-			}
-
-			// Both our currently available local services don't handle remote images, so we return the path as is.
 			return options.src;
 		}
 
-		if (!VALID_INPUT_FORMATS.includes(options.src.format as any)) {
-			throw new AstroError({
-				...AstroErrorData.UnsupportedImageFormat,
-				message: AstroErrorData.UnsupportedImageFormat.message(
-					options.src.format,
-					options.src.src,
-					VALID_INPUT_FORMATS
-				),
-			});
-		}
-
 		const searchParams = new URLSearchParams();
 		searchParams.append('href', options.src.src);
 
@@ -177,7 +197,7 @@ export const baseService: Omit<LocalImageService, 'transform'> = {
 			src: params.get('href')!,
 			width: params.has('w') ? parseInt(params.get('w')!) : undefined,
 			height: params.has('h') ? parseInt(params.get('h')!) : undefined,
-			format: params.get('f') as OutputFormat | null,
+			format: params.get('f') as OutputFormat,
 			quality: params.get('q'),
 		};
 

packages/astro/src/assets/services/sharp.ts

@@ -23,19 +23,14 @@ async function loadSharp() {
 }
 
 const sharpService: LocalImageService = {
+	validateOptions: baseService.validateOptions,
 	getURL: baseService.getURL,
 	parseURL: baseService.parseURL,
 	getHTMLAttributes: baseService.getHTMLAttributes,
 	async transform(inputBuffer, transformOptions) {
 		if (!sharp) sharp = await loadSharp();
 
-		const transform: BaseServiceTransform = transformOptions;
-
-		// If the user didn't specify a format, we'll default to `webp`. It offers the best ratio of compatibility / quality
-		// In the future, hopefully we can replace this with `avif`, alas, Edge. See https://caniuse.com/avif
-		if (!transform.format) {
-			transform.format = 'webp';
-		}
+		const transform: BaseServiceTransform = transformOptions as BaseServiceTransform;
 
 		let result = sharp(inputBuffer, { failOnError: false, pages: -1 });
 

packages/astro/src/assets/services/squoosh.ts

@@ -21,16 +21,14 @@ const qualityTable: Record<Exclude<OutputFormat, 'png'>, Record<ImageQualityPres
 };
 
 const service: LocalImageService = {
+	validateOptions: baseService.validateOptions,
 	getURL: baseService.getURL,
 	parseURL: baseService.parseURL,
 	getHTMLAttributes: baseService.getHTMLAttributes,
 	async transform(inputBuffer, transformOptions) {
 		const transform: BaseServiceTransform = transformOptions as BaseServiceTransform;
 
-		let format = transform.format;
-		if (!format) {
-			format = 'webp';
-		}
+		let format = transform.format!;
 
 		const operations: Operation[] = [];
 

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

@@ -13,6 +13,7 @@ import type { Plugin } from 'vite';
 import { normalizePath } from 'vite';
 import type { AstroSettings } from '../@types/astro';
 import { imageMetadata } from '../assets/index.js';
+import type { ImageService } from '../assets/services/service';
 import { AstroError, AstroErrorData, MarkdownError } from '../core/errors/index.js';
 import type { LogOptions } from '../core/logger/core.js';
 import { warn } from '../core/logger/core.js';
@@ -61,6 +62,8 @@ const astroJsxRuntimeModulePath = normalizePath(
 export default function markdown({ settings, logging }: AstroPluginOptions): Plugin {
 	const markdownAssetMap = new Map<string, string>();
 
+	let imageService: ImageService | undefined = undefined;
+
 	async function resolveImage(this: PluginContext, fileId: string, path: string) {
 		const resolved = await this.resolve(path, fileId);
 		if (!resolved) return path;
@@ -92,7 +95,6 @@ export default function markdown({ settings, logging }: AstroPluginOptions): Plu
 				const rawFile = await fs.promises.readFile(fileId, 'utf-8');
 				const raw = safeMatter(rawFile, id);
 
-				let imageService = undefined;
 				if (settings.config.experimental.assets) {
 					imageService = (await import(settings.config.image.service)).default;
 				}
@@ -219,10 +221,18 @@ export default function markdown({ settings, logging }: AstroPluginOptions): Plu
 						}
 						const fileName = this.getFileName(hash);
 						image.src = npath.join(settings.config.base, fileName);
-						const optimized = globalThis.astroAsset.addStaticImage!({ src: image });
+
+						// TODO: This part recreates code we already have for content collection and normal ESM imports.
+						// It might be possible to refactor so it also uses `emitESMImage`? - erika, 2023-03-15
+						const options = { src: image };
+						const validatedOptions = imageService?.validateOptions
+							? imageService.validateOptions(options)
+							: options;
+
+						const optimized = globalThis.astroAsset.addStaticImage!(validatedOptions);
 						optimizedPaths.set(hash, optimized);
 					}
-					output.code = output.code.replace(/ASTRO_ASSET_MD_([0-9a-z]{8})/, (_str, hash) => {
+					output.code = output.code.replaceAll(/ASTRO_ASSET_MD_([0-9a-z]{8})/gm, (_str, hash) => {
 						const optimizedName = optimizedPaths.get(hash);
 						return optimizedName || this.getFileName(hash);
 					});

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

@@ -308,6 +308,13 @@ describe('astro:image', () => {
 			expect(data).to.be.an.instanceOf(Buffer);
 		});
 
+		it('writes out images to dist folder with proper extension if no format was passed', async () => {
+			const html = await fixture.readFile('/index.html');
+			const $ = cheerio.load(html);
+			const src = $('#local img').attr('src');
+			expect(src.endsWith('.webp')).to.be.true;
+		});
+
 		it('getImage() usage also written', async () => {
 			const html = await fixture.readFile('/get-image/index.html');
 			const $ = cheerio.load(html);

packages/astro/test/fixtures/core-image/service.mjs

@@ -1,6 +1,9 @@
 import squoosh from 'astro/assets/services/squoosh';
 
 const service = {
+	validateOptions(options) {
+		return squoosh.validateOptions(options);
+	},
   getURL(options) {
 		return squoosh.getURL(options);
   },

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

@@ -39,11 +39,15 @@ export function rehypeImages(imageService: any, assetsDir: URL | undefined) {
 							alt: node.properties.alt,
 						};
 
-						const imageURL = imageService.getURL(options);
+						const validatedOptions = imageService.validateOptions
+							? imageService.validateOptions(options)
+							: options;
+
+						const imageURL = imageService.getURL(validatedOptions);
 						node.properties = Object.assign(node.properties, {
 							src: imageURL,
 							...(imageService.getHTMLAttributes !== undefined
-								? imageService.getHTMLAttributes(options)
+								? imageService.getHTMLAttributes(validatedOptions)
 								: {}),
 						});
 					}