Add link embeds to posts

src/state/models/link-metas-view.ts

@@ -0,0 +1,44 @@
+import {makeAutoObservable} from 'mobx'
+import {LRUMap} from 'lru_map'
+import {RootStoreModel} from './root-store'
+import {LinkMeta, getLinkMeta} from '../../lib/link-meta'
+
+type CacheValue = Promise<LinkMeta> | LinkMeta
+export class LinkMetasViewModel {
+  cache: LRUMap<string, CacheValue> = new LRUMap(100)
+
+  constructor(public rootStore: RootStoreModel) {
+    makeAutoObservable(
+      this,
+      {
+        rootStore: false,
+        cache: false,
+      },
+      {autoBind: true},
+    )
+  }
+
+  // public api
+  // =
+
+  async getLinkMeta(url: string) {
+    const cached = this.cache.get(url)
+    if (cached) {
+      try {
+        return await cached
+      } catch (e) {
+        // ignore, we'll try again
+      }
+    }
+    try {
+      const promise = getLinkMeta(url)
+      this.cache.set(url, promise)
+      const res = await promise
+      this.cache.set(url, res)
+      return res
+    } catch (e) {
+      this.cache.delete(url)
+      throw e
+    }
+  }
+}

src/state/models/root-store.ts

@@ -11,6 +11,7 @@ import {SessionModel} from './session'
 import {NavigationModel} from './navigation'
 import {ShellUiModel} from './shell-ui'
 import {ProfilesViewModel} from './profiles-view'
+import {LinkMetasViewModel} from './link-metas-view'
 import {MeModel} from './me'
 import {OnboardModel} from './onboard'
 
@@ -21,6 +22,7 @@ export class RootStoreModel {
   me = new MeModel(this)
   onboard = new OnboardModel()
   profiles = new ProfilesViewModel(this)
+  linkMetas = new LinkMetasViewModel(this)
 
   constructor(public api: SessionServiceClient) {
     makeAutoObservable(this, {