fix: render prompt museum media

src/lib/image-prompt-museum.ts

@@ -15,6 +15,21 @@ type PromptMuseumEnvelope<T> = {
   data?: T;
 };
 
+type PromptMuseumMedia = {
+  dataBase64: string;
+  mimeType: string;
+};
+
+const PROMPT_MUSEUM_MEDIA_URL_PATTERN = /^\/api\/image-prompt-museum\/[A-Za-z0-9][A-Za-z0-9._:-]{0,127}\/media\/(?:thumbnail|[0-9]+)$/;
+const PROMPT_MUSEUM_MEDIA_MIME_TYPES = new Set([
+  'image/avif',
+  'image/gif',
+  'image/jpeg',
+  'image/png',
+  'image/webp',
+]);
+const MAX_MEDIA_BASE64_LENGTH = Math.ceil((10 * 1024 * 1024) / 3) * 4;
+
 export class PromptMuseumApiError extends Error {
   readonly status: number;
   readonly code: string;
@@ -92,3 +107,23 @@ export async function fetchPromptMuseumPage(query: PromptMuseumListQuery = {}):
 export async function fetchPromptMuseumEntry(entryId: string): Promise<PromptMuseumEntry> {
   return await requestData(`${IMAGE_PROMPT_MUSEUM_API_PATH}/${encodeURIComponent(entryId)}`);
 }
+
+export async function fetchPromptMuseumMedia(mediaUrl: string): Promise<string> {
+  if (!PROMPT_MUSEUM_MEDIA_URL_PATTERN.test(mediaUrl)) {
+    throw new PromptMuseumApiError(400, 'PROMPT_MUSEUM_INVALID_MEDIA_URL', '提示词图片地址无效');
+  }
+  const localPath = mediaUrl.replace('/api/image-prompt-museum/', `${IMAGE_PROMPT_MUSEUM_API_PATH}/`);
+  const payload = await hostApiFetch<PromptMuseumMedia>(localPath);
+  const mimeType = typeof payload?.mimeType === 'string' ? payload.mimeType.trim().toLowerCase() : '';
+  const dataBase64 = typeof payload?.dataBase64 === 'string' ? payload.dataBase64 : '';
+  if (
+    !PROMPT_MUSEUM_MEDIA_MIME_TYPES.has(mimeType)
+    || !dataBase64
+    || dataBase64.length > MAX_MEDIA_BASE64_LENGTH
+    || !/^[A-Za-z0-9+/]*={0,2}$/.test(dataBase64)
+    || dataBase64.length % 4 === 1
+  ) {
+    throw new PromptMuseumApiError(502, 'PROMPT_MUSEUM_INVALID_MEDIA_RESPONSE', '提示词图片返回了无效数据');
+  }
+  return `data:${mimeType};base64,${dataBase64}`;
+}