Implement simple LRU cache for publisher info lookups

scripts/brave_rewards/publisher/common/lruCache.ts

@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+export class LruCache<T> {
+
+  private values: Map<string, T> = new Map<string, T>()
+  private maxEntries: number
+
+  constructor (maxEntries: number) {
+    this.maxEntries = maxEntries
+  }
+
+  public get (key: string): T | null {
+    if (!key) {
+      return null
+    }
+
+    const entry = this.values.get(key)
+    if (!entry) {
+      return null
+    }
+
+    this.values.delete(key)
+    this.values.set(key, entry)
+
+    return entry
+  }
+
+  public put (key: string, value: T) {
+    if (this.values.size >= this.maxEntries) {
+      const key = this.values.keys().next().value
+      this.values.delete(key)
+    }
+
+    this.values.set(key, value)
+  }
+}

scripts/brave_rewards/publisher/twitter/publisherInfo.ts

@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+import { LruCache } from '../common/lruCache'
 import { getPort } from '../common/messaging'
 
 import * as commonUtils from '../common/utils'
@@ -10,6 +11,41 @@ import * as api from './api'
 import * as types from './types'
 import * as utils from './utils'
 
+const userCache = new LruCache<any>(128)
+
+const savePublisherVisit = (screenName: string, userDetails: any) => {
+  if (!screenName || !userDetails) {
+    return
+  }
+
+  const userId = userDetails.id_str
+  const publisherKey =
+    commonUtils.buildPublisherKey(types.mediaType, userId)
+  const publisherName = screenName
+  const mediaKey = commonUtils.buildMediaKey(types.mediaType, screenName)
+  const favIconUrl =
+    userDetails.profile_image_url_https.replace('_normal', '')
+
+  const profileUrl = utils.buildProfileUrl(screenName, userId)
+
+  const port = getPort()
+  if (!port) {
+    return
+  }
+
+  port.postMessage({
+    type: 'SavePublisherVisit',
+    mediaType: types.mediaType,
+    data: {
+      url: profileUrl,
+      publisherKey,
+      publisherName,
+      mediaKey,
+      favIconUrl
+    }
+  })
+}
+
 const sendForExcludedPage = () => {
   const url = `https://${types.mediaDomain}`
   const publisherKey = types.mediaDomain
@@ -41,34 +77,16 @@ const sendForStandardPage = (url: URL) => {
     return
   }
 
+  const userDetails = userCache.get(screenName)
+  if (userDetails) {
+    savePublisherVisit(screenName, userDetails)
+    return
+  }
+
   api.getUserDetails(screenName)
     .then((userDetails: any) => {
-      const userId = userDetails.id_str
-      const publisherKey =
-        commonUtils.buildPublisherKey(types.mediaType, userId)
-      const publisherName = screenName
-      const mediaKey = commonUtils.buildMediaKey(types.mediaType, screenName)
-      const favIconUrl =
-        userDetails.profile_image_url_https.replace('_normal', '')
-
-      const profileUrl = utils.buildProfileUrl(screenName, userId)
-
-      const port = getPort()
-      if (!port) {
-        return
-      }
-
-      port.postMessage({
-        type: 'SavePublisherVisit',
-        mediaType: types.mediaType,
-        data: {
-          url: profileUrl,
-          publisherKey,
-          publisherName,
-          mediaKey,
-          favIconUrl
-        }
-      })
+      userCache.put(screenName, userDetails)
+      savePublisherVisit(screenName, userDetails)
     })
     .catch(error => {
       console.error(`Failed to fetch user details for ${screenName}: ${error.message}`)