Add caching to month summary results

src/Solar.Api/Constants/CacheKeys.cs

@@ -0,0 +1,9 @@
+namespace Solar.Api.Constants;
+
+internal static class CacheKeys
+{
+    public static string GetMonthSummaryCacheKey(string source, int year, int month)
+    {
+        return $"month-summary-{source}-{year}-{month}";
+    }
+}

src/Solar.Api/Controllers/SolarLogController.cs

@@ -1,8 +1,8 @@
-using System.Net.Mime;
 using Microsoft.AspNetCore.Mvc;
 using Solar.Api.Models;
 using Solar.Api.Services;
 using Swashbuckle.AspNetCore.Annotations;
+using System.Net.Mime;
 
 namespace Solar.Api.Controllers;
 

src/Solar.Api/Program.cs

@@ -1,9 +1,9 @@
-using System.Text.Json;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.OpenApi.Models;
 using Solar.Api.Converters;
 using Solar.Api.Services;
 using Swashbuckle.AspNetCore.SwaggerGen;
+using System.Text.Json;
 
 namespace Solar.Api;
 
@@ -15,6 +15,7 @@ public partial class Program
 
         // Services
         builder.Services.AddScoped<SolarService>();
+        builder.Services.AddMemoryCache();
 
         // Database
         builder.Services.AddDbContext<DatabaseContext>(options =>

src/Solar.Api/Services/SolarService.cs

@@ -1,4 +1,6 @@
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Caching.Memory;
+using Solar.Api.Constants;
 using Solar.Api.Entities;
 using Solar.Api.Models;
 
@@ -7,13 +9,16 @@ namespace Solar.Api.Services;
 public class SolarService
 {
     private readonly DatabaseContext databaseContext;
+    private readonly IMemoryCache memoryCache;
     private readonly ILogger<SolarService> logger;
 
     public SolarService(
         DatabaseContext databaseContext,
+        IMemoryCache memoryCache,
         ILogger<SolarService> logger)
     {
         this.databaseContext = databaseContext;
+        this.memoryCache = memoryCache;
 
         this.logger = logger;
     }
@@ -48,6 +53,20 @@ public class SolarService
                 .ToArray());
     }
 
+    private static void NormalizeEnvoyLogs(EnvoyLog[] entities)
+    {
+        if (entities.Length < 1)
+        {
+            return;
+        }
+
+        var baseValue = entities[0].TotalWatts;
+        foreach (var entity in entities)
+        {
+            entity.TotalWatts -= baseValue;
+        }
+    }
+
     public async Task<DaysResponse> GetDaySummaries(DateOnly start, DateOnly stop)
     {
         var zeverRecords = await databaseContext
@@ -73,30 +92,6 @@ public class SolarService
         return new DaysResponse(logs.ToArray());
     }
 
-    public async Task<MonthSummariesResponse> GetMonthSummaries(int fromYear, int fromMonth, int toYear, int toMonth)
-    {
-        var results = new List<MonthLog>();
-        var current = (Year: fromYear, Month: fromMonth);
-        do
-        {
-            var zeverResult = (int)await databaseContext.ZeverSummaries
-                .Where(zs => zs.Date.Year == current.Year && zs.Date.Month == current.Month)
-                .SumAsync(zs => zs.TotalWatts);
-            var envoyYear = await GetEnvoyMonthTotalWatts(current.Year, current.Month);
-            results.Add(new MonthLog(current.Year, current.Month, zeverResult, envoyYear));
-
-            if (current.Month == 12)
-            {
-                current = (current.Year + 1, 1);
-            }
-            else
-            {
-                current = (current.Year, current.Month + 1);
-            }
-        } while (current.Year < toYear || current.Month < toMonth);
-        return new MonthSummariesResponse(results.ToArray());
-    }
-
     private async Task<int> GetEnvoyDayTotalWatts(DateOnly date)
     {
         var min = await databaseContext.EnvoyLogs
@@ -116,6 +111,35 @@ public class SolarService
         return (int)(max.TotalWatts - min.TotalWatts);
     }
 
+    public async Task<MonthSummariesResponse> GetMonthSummaries(int fromYear, int fromMonth, int toYear, int toMonth)
+    {
+        var results = new List<MonthLog>();
+        var current = (Year: fromYear, Month: fromMonth);
+        do
+        {
+            var zeverResult = await GetOrAddToCache("zever", current.Year, current.Month, GetZeverMonthTotalWatts);
+            var envoyYear = await GetOrAddToCache("envoy", current.Year, current.Month, GetEnvoyMonthTotalWatts);
+            results.Add(new MonthLog(current.Year, current.Month, zeverResult, envoyYear));
+
+            if (current.Month == 12)
+            {
+                current = (current.Year + 1, 1);
+            }
+            else
+            {
+                current = (current.Year, current.Month + 1);
+            }
+        } while (current.Year < toYear || current.Month < toMonth);
+        return new MonthSummariesResponse(results.ToArray());
+    }
+
+    private async Task<int> GetZeverMonthTotalWatts(int year, int month)
+    {
+        return (int)await databaseContext.ZeverSummaries
+            .Where(zs => zs.Date.Year == year && zs.Date.Month == month)
+            .SumAsync(zs => zs.TotalWatts);
+    }
+
     private async Task<int> GetEnvoyMonthTotalWatts(int year, int month)
     {
         var min = await databaseContext.EnvoyLogs
@@ -135,17 +159,21 @@ public class SolarService
         return (int)(max.TotalWatts - min.TotalWatts);
     }
 
-    private static void NormalizeEnvoyLogs(EnvoyLog[] entities)
+    private async Task<int> GetOrAddToCache(
+        string source,
+        int year,
+        int month,
+        Func<int, int, Task<int>> fetchMethod)
     {
-        if (entities.Length < 1)
+        return await memoryCache.GetOrCreateAsync(
+            CacheKeys.GetMonthSummaryCacheKey(source, year, month),
+            async (cacheEntry) =>
             {
-            return;
-        }
-
-        var baseValue = entities[0].TotalWatts;
-        foreach (var entity in entities)
+                if (DateTime.Today.Month == month && DateTime.Today.Year == year)
                 {
-            entity.TotalWatts -= baseValue;
-        }
+                    cacheEntry.SlidingExpiration = TimeSpan.FromHours(12);
+                }
+                return await fetchMethod(year, month);
+            });
     }
 }