feat: blurhash

src/lib/event.ts

@@ -1,7 +1,7 @@
 import { COMMENT_EVENT_KIND, PICTURE_EVENT_KIND } from '@/constants'
 import client from '@/services/client.service'
 import { Event, kinds, nip19 } from 'nostr-tools'
-import { extractImetaUrlFromTag, isReplyETag, isRootETag, tagNameEquals } from './tag'
+import { extractImageInfoFromTag, isReplyETag, isRootETag, tagNameEquals } from './tag'
 
 export function isNsfwEvent(event: Event) {
   return event.tags.some(
@@ -200,7 +200,7 @@ export function extractHashtags(content: string) {
 export function extractFirstPictureFromPictureEvent(event: Event) {
   if (!isPictureEvent(event)) return null
   for (const tag of event.tags) {
-    const url = extractImetaUrlFromTag(tag)
+    const url = extractImageInfoFromTag(tag)
     if (url) return url
   }
   return null

src/lib/tag.ts

@@ -1,3 +1,6 @@
+import { TImageInfo } from '@/types'
+import { isBlurhashValid } from 'blurhash'
+
 export function tagNameEquals(tagName: string) {
   return (tag: string[]) => tag[0] === tagName
 }
@@ -14,9 +17,28 @@ export function isMentionETag([tagName, , , marker]: string[]) {
   return tagName === 'e' && marker === 'mention'
 }
 
-export function extractImetaUrlFromTag(tag: string[]) {
+export function extractImageInfoFromTag(tag: string[]): TImageInfo | null {
   if (tag[0] !== 'imeta') return null
   const urlItem = tag.find((item) => item.startsWith('url '))
   const url = urlItem?.slice(4)
-  return url || null
+  if (!url) return null
+
+  const image: TImageInfo = { url }
+  const blurHashItem = tag.find((item) => item.startsWith('blurhash '))
+  const blurHash = blurHashItem?.slice(9)
+  if (blurHash) {
+    const validRes = isBlurhashValid(blurHash)
+    if (validRes.result) {
+      image.blurHash = blurHash
+    }
+  }
+  const dimItem = tag.find((item) => item.startsWith('dim '))
+  const dim = dimItem?.slice(4)
+  if (dim) {
+    const [width, height] = dim.split('x').map(Number)
+    if (width && height) {
+      image.dim = { width, height }
+    }
+  }
+  return image
 }