improvement(caching): implement client-side caching for listing and p…

…rofile data (#52)

src/models/Cache.test.ts

@@ -0,0 +1,42 @@
+import { Cache } from './Cache'
+
+test('Properly initialize initial object state', () => {
+  const cache = new Cache()
+  expect(JSON.stringify(cache)).toEqual(JSON.stringify({ cache: {} }))
+})
+
+test('Add cache entry', () => {
+  const cache = new Cache()
+  const realDateNow = Date.now.bind(global.Date)
+  const dateNowStub = jest.fn(() => 3600000)
+  global.Date.now = dateNowStub
+  cache.store('test-key', 'test-value')
+
+  expect(cache.retrieve('test-key')).toEqual('test-value')
+  expect(JSON.stringify(cache)).toEqual(
+    JSON.stringify({
+      cache: {
+        'test-key': {
+          data: 'test-value',
+          expiresOn: 3600000 + 3600000,
+        },
+      },
+    })
+  )
+})
+
+test('Cache expiration', () => {
+  const cache = new Cache()
+  const realDateNow = Date.now.bind(global.Date)
+  const dateNowStub = jest.fn(() => 3600000)
+  global.Date.now = dateNowStub
+  cache.store('test-key', 'test-value')
+
+  const dateExpireStub = jest.fn(() => 3600000 + 3600000)
+  global.Date.now = dateExpireStub
+
+  expect(cache.hasExpired('test-key')).toBe(true)
+  expect(cache.retrieve('test-key')).toBe(false)
+
+  global.Date.now = realDateNow
+})

src/models/Cache.ts

@@ -0,0 +1,50 @@
+interface CacheInterface {
+  [key: string]: CacheData
+}
+
+interface CacheData {
+  data: any
+  expiresOn: number
+}
+
+class Cache {
+  private cache: CacheInterface = {}
+
+  constructor(props?) {
+    if (props) {
+      Object.assign(this, props)
+    }
+  }
+
+  public store(key: string, data: any) {
+    const expiresOn = Date.now() + 3600000
+    this.cache[key] = { data, expiresOn }
+  }
+
+  public retrieve(key: string) {
+    if (this.cache[key]) {
+      if (this.hasExpired(key)) {
+        delete this.cache[key]
+        return false
+      }
+      /**
+       * Cloning object to avoid unintentional mutations
+       */
+      return JSON.parse(JSON.stringify(this.cache[key].data))
+    } else {
+      return false
+    }
+  }
+
+  public delete(key: string) {
+    delete this.cache[key]
+  }
+
+  public hasExpired(key: string) {
+    const cacheData = this.cache[key]
+    return cacheData.expiresOn <= Date.now()
+  }
+}
+
+const cacheInstance = new Cache()
+export { cacheInstance, Cache }

src/models/Listing.ts

@@ -15,6 +15,7 @@ import {
 } from '../interfaces/Listing'
 import Location from '../interfaces/Location'
 import Rating, { RatingSummary } from '../interfaces/Rating'
+import { cacheInstance } from './Cache'
 import currency from './Currency'
 import Profile from './Profile'
 
@@ -28,31 +29,37 @@ export interface ListingResponse {
 
 class Listing implements ListingInterface {
   public static async retrieve(id: string): Promise<ListingResponse> {
-    const kimitzuListingRequest = await Axios.get(
-      `${config.kimitzuHost}/kimitzu/listing?hash=${id}`
-    )
-    const kimitzuListing = kimitzuListingRequest.data
+    let rawListingData
 
-    /**
-     * Load profile from cache.
-     */
-    const vendor = await Profile.retrieve(kimitzuListing.vendorID.peerID, false)
+    if (cacheInstance.retrieve(id)) {
+      rawListingData = cacheInstance.retrieve(id)
+    } else {
+      const kimitzuListingRequest = await Axios.get(
+        `${config.kimitzuHost}/kimitzu/listing?hash=${id}`
+      )
+      rawListingData = kimitzuListingRequest.data
+      cacheInstance.store(id, rawListingData)
+      rawListingData = cacheInstance.retrieve(id)
+    }
+
+    const vendor = await Profile.retrieve(rawListingData.vendorID.peerID, false)
 
-    const imageData = kimitzuListing.item.images.map((image: Image) => {
+    const imageData = rawListingData.item.images.map((image: Image) => {
       return { src: `${config.openBazaarHost}/ob/images/${image.medium}` }
     })
 
     const currentUser = await Profile.retrieve('', false)
 
-    const listing = new Listing(kimitzuListing)
+    const listing = new Listing(rawListingData)
     listing.currentUser = currentUser
     listing.isOwner = currentUser.peerID === listing.vendorID.peerID
 
     /**
      * Return vendor profile, listing information, and image sources separately
      * to avoid complicated mutations in the listing object.
      */
-    return { vendor, listing, imageData }
+    const processedListingData = { vendor, listing, imageData }
+    return processedListingData
   }
 
   public currentUser: Profile = new Profile()

src/models/Profile.ts

@@ -21,6 +21,7 @@ import Rating, { RatingSummary } from '../interfaces/Rating'
 import isElectron from 'is-electron'
 import defaults from '../constants/Defaults'
 import decodeHtml from '../utils/Unescape'
+import { cacheInstance } from './Cache'
 
 const profileDefaults = defaults.profile
 const LOCATION_TYPES = ['primary', 'shipping', 'billing', 'return']
@@ -163,6 +164,12 @@ class Profile implements ProfileSchema {
   public static async retrieve(id?: string, force?: boolean): Promise<Profile> {
     let profile: Profile
 
+    const cacheId = id ? id : '~self'
+    const profileCache = cacheInstance.retrieve(cacheId)
+    if (profileCache) {
+      return profileCache
+    }
+
     try {
       if (id) {
         const peerRequest = await Axios.get(
@@ -204,6 +211,7 @@ class Profile implements ProfileSchema {
       profile.moderatorInfo.fee.fixedFee.amount = profile.moderatorInfo.fee.fixedFee.amount / 100
     }
 
+    cacheInstance.store(cacheId, profile)
     return profile
   }
 
@@ -329,6 +337,7 @@ class Profile implements ProfileSchema {
   }
 
   public async save() {
+    cacheInstance.delete('~self')
     this.location = this.getAddress('primary')
     await Axios.post(`${config.openBazaarHost}/ob/profile`, this)
     await Profile.publish()
@@ -356,6 +365,7 @@ class Profile implements ProfileSchema {
   }
 
   public async update() {
+    cacheInstance.delete('~self')
     this.location = this.getAddress('primary')
     this.preSave()
     await Axios.put(`${config.openBazaarHost}/ob/profile`, this)