fix(@desktop/wallet): cache currency format

Fixes #9132

src/app_service/common/cache.nim

@@ -0,0 +1,22 @@
+
+import tables, times
+
+export tables, times
+
+type Value*[T] = ref object
+  value*: T
+  timestamp*: DateTime
+
+type TimedCache*[T] = Table[string, Value[T]]
+
+proc newTimedCache*[T](): TimedCache[T] = initTable[string, Value[T]]()
+
+proc getTimestamp[T](self: TimedCache[T], cacheKey: string): DateTime = self[cacheKey].timestamp
+
+proc isCached*[T](self: TimedCache[T], cacheKey: string, duration=initDuration(minutes = 5)): bool =
+  self.hasKey(cacheKey) and ((self.getTimestamp(cacheKey) + duration) >= now())
+
+proc set*[T](self: var TimedCache[T], cacheKey: string, value: T) =
+  self[cacheKey] = Value[T](value: value, timestamp: now())
+
+proc get*[T](self: TimedCache[T], cacheKey: string): T = self[cacheKey].value

src/app_service/service/currency/service.nim

@@ -1,7 +1,8 @@
-import NimQml, strformat, strutils
+import NimQml, strformat, strutils, tables
 import ../settings/service as settings_service
 import ../token/service as token_service
 import ./dto, ./utils
+import ../../common/cache
 
 export dto
 
@@ -11,6 +12,9 @@ QtObject:
   type Service* = ref object of QObject
     tokenService: token_service.Service
     settingsService: settings_service.Service
+    isCurrencyFiatCache: Table[string, bool]                    # Fiat info does not change, we can fetch/calculate once and
+    fiatCurrencyFormatCache: Table[string, CurrencyFormatDto]   # keep the results forever.
+    tokenCurrencyFormatCache: TimedCache[CurrencyFormatDto]     # Token format changes with price, so we use a timed cache.
 
   proc delete*(self: Service) =
     self.QObject.delete
@@ -23,33 +27,50 @@ QtObject:
     result.QObject.setup
     result.tokenService = tokenService
     result.settingsService = settingsService
+    result.tokenCurrencyFormatCache = newTimedCache[CurrencyFormatDto]()
 
   proc init*(self: Service) =
     discard
 
+  proc isCurrencyFiat(self: Service, symbol: string): bool =
+    if not self.isCurrencyFiatCache.hasKey(symbol):
+      self.isCurrencyFiatCache[symbol] = isCurrencyFiat(symbol)
+    return self.isCurrencyFiatCache[symbol]
+
   proc getFiatCurrencyFormat(self: Service, symbol: string): CurrencyFormatDto =
-    return CurrencyFormatDto(
-      symbol: toUpperAscii(symbol),
-      displayDecimals: getFiatDisplayDecimals(symbol),
-      stripTrailingZeroes: false
-    )
+    if not self.fiatCurrencyFormatCache.hasKey(symbol):
+      self.fiatCurrencyFormatCache[symbol] = CurrencyFormatDto(
+        symbol: toUpperAscii(symbol),
+        displayDecimals: getFiatDisplayDecimals(symbol),
+        stripTrailingZeroes: false
+      )
+    return self.fiatCurrencyFormatCache[symbol]
 
   proc getTokenCurrencyFormat(self: Service, symbol: string): CurrencyFormatDto =
+    if self.tokenCurrencyFormatCache.isCached(symbol):
+      return self.tokenCurrencyFormatCache.get(symbol)
+
+    var updateCache = true
     let pegSymbol = self.tokenService.getTokenPegSymbol(symbol)
     if pegSymbol != "":
       var currencyFormat = self.getFiatCurrencyFormat(pegSymbol)
       currencyFormat.symbol = symbol
-      return currencyFormat
+      result = currencyFormat
+      updateCache = true
     else:
-      let price = self.tokenService.getTokenPrice(symbol, DECIMALS_CALCULATION_CURRENCY, false)
-      return CurrencyFormatDto(
+      let price = self.tokenService.getCachedTokenPrice(symbol, DECIMALS_CALCULATION_CURRENCY)
+      result = CurrencyFormatDto(
         symbol: symbol,
         displayDecimals: getTokenDisplayDecimals(price),
         stripTrailingZeroes: true
       )
+      updateCache = self.tokenService.isCachedTokenPriceRecent(symbol, DECIMALS_CALCULATION_CURRENCY)
+
+    if updateCache:
+      self.tokenCurrencyFormatCache.set(symbol, result)
 
   proc getCurrencyFormat*(self: Service, symbol: string): CurrencyFormatDto =
-    if isCurrencyFiat(symbol):
+    if self.isCurrencyFiat(symbol):
       return self.getFiatCurrencyFormat(symbol)
     else:
       return self.getTokenCurrencyFormat(symbol)

src/app_service/service/token/service.nim

@@ -11,7 +11,7 @@ import ../../../app/global/global_singleton
 
 import ../../../app/core/eventemitter
 import ../../../app/core/tasks/[qt, threadpool]
-import ../../../backend/cache
+import ../../common/cache
 import ./dto
 
 export dto
@@ -39,7 +39,7 @@ QtObject:
     threadpool: ThreadPool
     networkService: network_service.Service
     tokens: Table[int, seq[TokenDto]]
-    priceCache: TimedCache
+    priceCache: TimedCache[float64]
 
   proc updateCachedTokenPrice(self: Service, crypto: string, fiat: string, price: float64)
 
@@ -57,7 +57,7 @@ QtObject:
     result.threadpool = threadpool
     result.networkService = networkService
     result.tokens = initTable[int, seq[TokenDto]]()
-    result.priceCache = newTimedCache()
+    result.priceCache = newTimedCache[float64]()
 
   proc init*(self: Service) =
     try:
@@ -130,19 +130,29 @@ QtObject:
   proc getTokenPriceCacheKey(crypto: string, fiat: string) : string =
     return renameSymbol(crypto) & renameSymbol(fiat)
 
-  proc getTokenPrice*(self: Service, crypto: string, fiat: string, fetchIfNotAvailable: bool = true): float64 =
+  proc isCachedTokenPriceRecent*(self: Service, crypto: string, fiat: string): bool =
+    let cacheKey = getTokenPriceCacheKey(crypto, fiat)
+    return self.priceCache.isCached(cacheKey)
+
+  proc getCachedTokenPrice*(self: Service, crypto: string, fiat: string): float64 =
     let cacheKey = getTokenPriceCacheKey(crypto, fiat)
-    if self.priceCache.isCached(cacheKey) or (self.priceCache.hasKey(cacheKey) and not fetchIfNotAvailable):
-      return parseFloat(self.priceCache.get(cacheKey))
-    elif not fetchIfNotAvailable:
+    if self.priceCache.hasKey(cacheKey):
+      return self.priceCache.get(cacheKey)
+    else:
       return 0.0
+
+  proc getTokenPrice*(self: Service, crypto: string, fiat: string, fetchIfNotAvailable: bool = true): float64 =
+    let cacheKey = getTokenPriceCacheKey(crypto, fiat)
+    if self.priceCache.isCached(cacheKey):
+      return self.priceCache.get(cacheKey)
     var prices = initTable[string, Table[string, float]]()
 
     try:
       let cryptoKey = renameSymbol(crypto)
       let fiatKey = renameSymbol(fiat)
       let response = backend.fetchPrices(@[cryptoKey], @[fiatKey])
       for (symbol, pricePerCurrency) in response.result.pairs:
+        prices[symbol] = initTable[string, float]()
         for (currency, price) in pricePerCurrency.pairs:
           prices[symbol][currency] = price.getFloat
 
@@ -155,7 +165,7 @@ QtObject:
 
   proc updateCachedTokenPrice(self: Service, crypto: string, fiat: string, price: float64) =
     let cacheKey = getTokenPriceCacheKey(crypto, fiat)
-    self.priceCache.set(cacheKey, $price)
+    self.priceCache.set(cacheKey, price)
 
   proc getTokenPegSymbol*(self: Service, symbol: string): string = 
     for _, tokens in self.tokens: