handle hashtags in statuses

 - by parsing them in enrichStatus
 - implementing a tag page to show their timeline

resolves #345

backend/src/mastodon/microformats.ts

@@ -13,14 +13,24 @@ function tag(name: string, content: string, attrs: Record<string, string> = {}):
 
 const linkRegex = /(^|\s|\b)(https?:\/\/[-\w@:%._+~#=]{2,256}\.[a-z]{2,6}\b(?:[-\w@:%_+.~#?&/=]*))(\b|\s|$)/g
 const mentionedEmailRegex = /(^|\s|\b|\W)@(\w+(?:[.-]?\w+)+@\w+(?:[.-]?\w+)+(?:\.\w{2,63})+)(\b|\s|$)/g
+const tagRegex = /(^|\s|\b|\W)#(\w{2,63})(\b|\s|$)/g
 
-/// Transform a text status into a HTML status; enriching it with links / mentions.
+// Transform a text status into a HTML status; enriching it with links / mentions.
 export function enrichStatus(status: string, mentions: Array<Actor>): string {
-	const enrichedStatus = status
+	const anchorsPlaceholdersMap = new Map<string, string>()
+
+	const getLinkAnchorPlaceholder = (link: string) => {
+		const anchor = getLinkAnchor(link)
+		const placeholder = `%%%___-LINK-PLACEHOLDER-${crypto.randomUUID()}-__%%%`
+		anchorsPlaceholdersMap.set(placeholder, anchor)
+		return placeholder
+	}
+
+	let enrichedStatus = status
 		.replace(
 			linkRegex,
 			(_, matchPrefix: string, link: string, matchSuffix: string) =>
-				`${matchPrefix}${getLinkAnchor(link)}${matchSuffix}`
+				`${matchPrefix}${getLinkAnchorPlaceholder(link)}${matchSuffix}`
 		)
 		.replace(mentionedEmailRegex, (_, matchPrefix: string, email: string, matchSuffix: string) => {
 			// ensure that the match is part of the mentions array
@@ -33,6 +43,15 @@ export function enrichStatus(status: string, mentions: Array<Actor>): string {
 			// otherwise the match isn't valid and we don't add HTML
 			return `${matchPrefix}${email}${matchSuffix}`
 		})
+		.replace(
+			tagRegex,
+			(_, matchPrefix: string, tag: string, matchSuffix: string) =>
+				`${matchPrefix}${/^\d+$/.test(tag) ? `#${tag}` : getTagAnchor(tag)}${matchSuffix}`
+		)
+
+	for (const [placeholder, anchor] of anchorsPlaceholdersMap.entries()) {
+		enrichedStatus = enrichedStatus.replace(placeholder, anchor)
+	}
 
 	return tag('p', enrichedStatus)
 }
@@ -60,3 +79,12 @@ function getLinkAnchor(link: string) {
 		return link
 	}
 }
+
+function getTagAnchor(hashTag: string) {
+	try {
+		return tag('a', `#${hashTag}`, { href: `/tags/${hashTag.replace(/^#/, '')}`, class: 'status-link hashtag' })
+	} catch (err: unknown) {
+		console.warn('failed to parse link', err)
+		return tag
+	}
+}

backend/test/mastodon.spec.ts

@@ -198,6 +198,51 @@ describe('Mastodon APIs', () => {
 				assert.equal(enrichStatus(`@!@£${link}!!!`, []), `<p>@!@£<a href="${link}">${urlDisplayText}</a>!!!</p>`)
 			})
 		})
+
+		test('convert tags to HTML', async () => {
+			const tagsToTest = [
+				{
+					tag: '#test',
+					expectedTagAnchor: '<a href="/tags/test" class="status-link hashtag">#test</a>',
+				},
+				{
+					tag: '#123_joke_123',
+					expectedTagAnchor: '<a href="/tags/123_joke_123" class="status-link hashtag">#123_joke_123</a>',
+				},
+				{
+					tag: '#_123',
+					expectedTagAnchor: '<a href="/tags/_123" class="status-link hashtag">#_123</a>',
+				},
+				{
+					tag: '#example:',
+					expectedTagAnchor: '<a href="/tags/example" class="status-link hashtag">#example</a>:',
+				},
+				{
+					tag: '#tagA#tagB',
+					expectedTagAnchor:
+						'<a href="/tags/tagA" class="status-link hashtag">#tagA</a><a href="/tags/tagB" class="status-link hashtag">#tagB</a>',
+				},
+			]
+
+			for (let i = 0, len = tagsToTest.length; i < len; i++) {
+				const { tag, expectedTagAnchor } = tagsToTest[i]
+
+				assert.equal(enrichStatus(`hey ${tag} hi`, []), `<p>hey ${expectedTagAnchor} hi</p>`)
+				assert.equal(enrichStatus(`${tag} hi`, []), `<p>${expectedTagAnchor} hi</p>`)
+				assert.equal(enrichStatus(`${tag}\n\thein`, []), `<p>${expectedTagAnchor}\n\thein</p>`)
+				assert.equal(enrichStatus(`hey ${tag}`, []), `<p>hey ${expectedTagAnchor}</p>`)
+				assert.equal(enrichStatus(`${tag}`, []), `<p>${expectedTagAnchor}</p>`)
+				assert.equal(enrichStatus(`@!@£${tag}!!!`, []), `<p>@!@£${expectedTagAnchor}!!!</p>`)
+			}
+		})
+
+		test('ignore invalid tags', () => {
+			assert.equal(enrichStatus('tags cannot be empty like: #', []), `<p>tags cannot be empty like: #</p>`)
+			assert.equal(
+				enrichStatus('tags cannot contain only numbers like: #123', []),
+				`<p>tags cannot contain only numbers like: #123</p>`
+			)
+		})
 	})
 
 	describe('Follow', () => {

frontend/src/components/StickyHeader/StickyHeader.tsx

@@ -1,30 +1,37 @@
 import { $, component$, Slot } from '@builder.io/qwik'
 import { useNavigate } from '@builder.io/qwik-city'
 
-export default component$<{ withBackButton?: boolean }>(({ withBackButton }) => {
-	const nav = useNavigate()
+export default component$<{ withBackButton?: boolean; backButtonPlacement?: 'start' | 'end' }>(
+	({ withBackButton, backButtonPlacement = 'start' }) => {
+		const nav = useNavigate()
 
-	const goBack = $(() => {
-		if (window.history.length > 1) {
-			window.history.back()
-		} else {
-			nav('/explore')
-		}
-	})
+		const goBack = $(() => {
+			if (window.history.length > 1) {
+				window.history.back()
+			} else {
+				nav('/explore')
+			}
+		})
 
-	return (
-		<header class="bg-wildebeest-900 sticky top-[3.9rem] xl:top-0 xl:pt-2.5 z-10">
-			<div class="flex bg-wildebeest-700 xl:rounded-t overflow-hidden">
-				{!!withBackButton && (
-					<div class="flex justify-between items-center bg-wildebeest-700">
-						<button class="text-semi no-underline text-wildebeest-vibrant-400 bg-transparent p-4" onClick$={goBack}>
-							<i class="fa fa-chevron-left mr-2 w-3 inline-block" />
-							<span class="hover:underline">Back</span>
-						</button>
-					</div>
-				)}
-				<Slot />
+		const backButton = !withBackButton ? (
+			// eslint-disable-next-line qwik/single-jsx-root
+			<></>
+		) : (
+			<div class="flex justify-between items-center bg-wildebeest-700">
+				<button class="text-semi no-underline text-wildebeest-vibrant-400 bg-transparent p-4" onClick$={goBack}>
+					<i class="fa fa-chevron-left mr-2 w-3 inline-block" />
+					<span class="hover:underline">Back</span>
+				</button>
 			</div>
-		</header>
-	)
-})
+		)
+		return (
+			<header class="bg-wildebeest-900 sticky top-[3.9rem] xl:top-0 xl:pt-2.5 z-10">
+				<div class="flex bg-wildebeest-700 xl:rounded-t overflow-hidden">
+					{backButtonPlacement === 'start' && backButton}
+					<Slot />
+					{backButtonPlacement === 'end' && <div class="ml-auto">{backButton}</div>}
+				</div>
+			</header>
+		)
+	}
+)

frontend/src/dummyData/statuses.ts

@@ -31,7 +31,15 @@ const mastodonRawStatuses: MastodonStatus[] = [
 		content: '<span>A very simple update: all good!</span>',
 		account: ben,
 	}),
-	generateDummyStatus({ content: '<p>Hi! My name is Rafael! 👋</p>', account: rafael, spoiler_text: 'who am I?' }),
+	generateDummyStatus({
+		content: '<p>Hi! My name is Rafael! 👋</p>',
+		account: rafael,
+		spoiler_text: 'who am I?',
+	}),
+	generateDummyStatus({
+		content: '<p>Hi! I made a funny! 🤭 <a href="/tags/joke" class="status-link hashtag">#joke</a></p>',
+		account: george,
+	}),
 	generateDummyStatus({
 		content: "<div><p>I'm Rafael and I am a web designer!</p><p>💪💪</p></div>",
 		account: rafael,

frontend/src/routes/(frontend)/tags/[tag]/index.tsx

@@ -0,0 +1,69 @@
+import { $, component$ } from '@builder.io/qwik'
+import { DocumentHead, loader$ } from '@builder.io/qwik-city'
+import { getDatabase } from 'wildebeest/backend/src/database'
+import { getDomain } from 'wildebeest/backend/src/utils/getDomain'
+import { handleRequest } from 'wildebeest/functions/api/v1/timelines/tag/[tag]'
+import { StatusesPanel } from '~/components/StatusesPanel/StatusesPanel'
+import StickyHeader from '~/components/StickyHeader/StickyHeader'
+import { MastodonStatus } from '~/types'
+import { getDocumentHead } from '~/utils/getDocumentHead'
+
+export const loader = loader$<Promise<{ tag: string; statuses: MastodonStatus[] }>, { DATABASE: D1Database }>(
+	async ({ request, platform, params }) => {
+		const tag = params.tag
+		const response = await handleRequest(await getDatabase(platform), request, getDomain(request.url), tag)
+		const results = await response.text()
+		const statuses: MastodonStatus[] = JSON.parse(results)
+		return { tag, statuses }
+	}
+)
+
+export default component$(() => {
+	const loaderData = loader()
+
+	return (
+		<>
+			<div class="flex flex-col flex-1">
+				<StickyHeader withBackButton backButtonPlacement="end">
+					<h2 class="text-reg text-md m-0 p-4 flex bg-wildebeest-700">
+						<i class="fa fa-hashtag fa-fw mr-3 w-5 leading-tight inline-block" />
+						<span>{loaderData.value.tag}</span>
+					</h2>
+				</StickyHeader>
+				<StatusesPanel
+					initialStatuses={loaderData.value.statuses}
+					fetchMoreStatuses={$(async (numOfCurrentStatuses: number) => {
+						let statuses: MastodonStatus[] = []
+						try {
+							const response = await fetch(
+								`/api/v1/timelines/tags/${loaderData.value.tag}/?offset=${numOfCurrentStatuses}`
+							)
+							if (response.ok) {
+								const results = await response.text()
+								statuses = JSON.parse(results)
+							}
+						} catch {
+							/* empty */
+						}
+						return statuses
+					})}
+				/>
+			</div>
+		</>
+	)
+})
+
+export const requestUrlLoader = loader$(async ({ request }) => request.url)
+
+export const head: DocumentHead = ({ resolveValue }) => {
+	const { tag } = resolveValue(loader)
+	const url = resolveValue(requestUrlLoader)
+
+	return getDocumentHead({
+		title: `#${tag} - Wildebeest`,
+		description: `#${tag} tag page - Wildebeest`,
+		og: {
+			url,
+		},
+	})
+}

functions/api/v1/timelines/tag/[tag].ts

@@ -3,23 +3,32 @@ import { cors } from 'wildebeest/backend/src/utils/cors'
 import type { ContextData } from 'wildebeest/backend/src/types/context'
 import * as timelines from 'wildebeest/backend/src/mastodon/timeline'
 import { type Database, getDatabase } from 'wildebeest/backend/src/database'
+import { getDomain } from 'wildebeest/backend/src/utils/getDomain'
 
 const headers = {
 	...cors(),
 	'content-type': 'application/json; charset=utf-8',
 }
 
 export const onRequest: PagesFunction<Env, any, ContextData> = async ({ request, env, params }) => {
-	const domain = new URL(request.url).hostname
-	return handleRequest(await getDatabase(env), request, domain, params.tag as string)
+	const url = new URL(request.url)
+	const { searchParams } = url
+	const offset = Number.parseInt(searchParams.get('offset') ?? '0')
+	return handleRequest(await getDatabase(env), request, getDomain(url), params.tag as string, offset)
 }
 
-export async function handleRequest(db: Database, request: Request, domain: string, tag: string): Promise<Response> {
+export async function handleRequest(
+	db: Database,
+	request: Request,
+	domain: string,
+	tag: string,
+	offset = 0
+): Promise<Response> {
 	const url = new URL(request.url)
 	if (url.searchParams.has('max_id')) {
 		return new Response(JSON.stringify([]), { headers })
 	}
 
-	const timeline = await timelines.getPublicTimeline(domain, db, timelines.LocalPreference.NotSet, 0, tag)
+	const timeline = await timelines.getPublicTimeline(domain, db, timelines.LocalPreference.NotSet, offset, tag)
 	return new Response(JSON.stringify(timeline), { headers })
 }

ui-e2e-tests/seo.spec.ts

@@ -71,6 +71,17 @@ test.describe('Presence of appropriate SEO metadata across the application', ()
 		})
 	})
 
+	test('in tag page', async ({ page }) => {
+		await page.goto('http://127.0.0.1:8788/tags/my-tag')
+		await checkPageSeoData(page, {
+			title: '#my-tag - Wildebeest',
+			description: '#my-tag tag page - Wildebeest',
+			ogType: 'website',
+			ogUrl: 'http://127.0.0.1:8788/tags/my-tag',
+			ogImage: 'https://imagedelivery.net/NkfPDviynOyTAOI79ar_GQ/b24caf12-5230-48c4-0bf7-2f40063bd400/thumbnail',
+		})
+	})
+
 	// To unskip when we enable the about page
 	test.skip('in about page', async ({ page }) => {
 		await page.goto('http://127.0.0.1:8788/about')