feat: link previews on MD

src/Utils/link-preview.ts

@@ -0,0 +1,42 @@
+import { WAUrlInfo } from '../Types'
+import { extractImageThumb, getHttpStream } from './messages-media'
+
+const THUMBNAIL_WIDTH_PX = 128
+
+/** Fetches an image and generates a thumbnail for it */
+const getCompressedJpegThumbnail = async(url: string) => {
+	const stream = await getHttpStream(url)
+	const result = await extractImageThumb(stream, THUMBNAIL_WIDTH_PX)
+	return result
+}
+
+/**
+ * Given a piece of text, checks for any URL present, generates link preview for the same and returns it
+ * Return undefined if the fetch failed or no URL was found
+ * @param text the text containing URL
+ * @returns the URL info required to generate link preview
+ */
+export const getUrlInfo = async(text: string): Promise<WAUrlInfo | undefined> => {
+	try {
+		const { getLinkPreview } = await import('link-preview-js')
+
+		const info = await getLinkPreview(text)
+		if(info && 'title' in info) {
+			const [image] = info.images
+
+			const jpegThumbnail = image ? await getCompressedJpegThumbnail(image) : undefined
+
+			return {
+				'canonical-url': info.url,
+				'matched-text': info.url,
+				title: info.title,
+				description: info.description,
+				jpegThumbnail
+			}
+		}
+	} catch(error) {
+		if(!error.message.includes('receive a valid')) {
+			throw error
+		}
+	}
+}

src/Utils/messages-media.ts

@@ -91,7 +91,7 @@ const extractVideoThumb = async(
     	})
 }) as Promise<void>
 
-export const extractImageThumb = async(bufferOrFilePath: Readable | Buffer | string) => {
+export const extractImageThumb = async(bufferOrFilePath: Readable | Buffer | string, width = 32) => {
 	if(bufferOrFilePath instanceof Readable) {
 		bufferOrFilePath = await toBuffer(bufferOrFilePath)
 	}
@@ -99,7 +99,7 @@ export const extractImageThumb = async(bufferOrFilePath: Readable | Buffer | str
 	const lib = await getImageProcessingLibrary()
 	if('sharp' in lib) {
 		const result = await lib.sharp!.default(bufferOrFilePath)
-			.resize(32)
+			.resize(width)
 			.jpeg({ quality: 50 })
 			.toBuffer()
 		return result
@@ -109,7 +109,7 @@ export const extractImageThumb = async(bufferOrFilePath: Readable | Buffer | str
 		const jimp = await read(bufferOrFilePath as any)
 		const result = await jimp
 			.quality(50)
-			.resize(32, AUTO, RESIZE_BILINEAR)
+			.resize(width, AUTO, RESIZE_BILINEAR)
 			.getBufferAsync(MIME_JPEG)
 		return result
 	}