From 1930ea97c29d58921692abd1b3fd603bcefa67c8 Mon Sep 17 00:00:00 2001
From: Miss Pasture <miss@pasture.moe>
Date: Mon, 24 May 2021 13:24:27 -0400
Subject: [PATCH] Cache tweets

---
 .../CachedTwitterTweetService.cs              | 63 +++++++++++++++++++
 ...Service.cs => CachedTwitterUserService.cs} |  0
 src/BirdsiteLive/BirdsiteLive.csproj          |  1 +
 .../Controllers/UsersController.cs            |  1 +
 src/BirdsiteLive/Startup.cs                   |  6 +-
 5 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 src/BirdsiteLive.Twitter/CachedTwitterTweetService.cs
 rename src/BirdsiteLive.Twitter/{CachedTwitterService.cs => CachedTwitterUserService.cs} (100%)

diff --git a/src/BirdsiteLive.Twitter/CachedTwitterTweetService.cs b/src/BirdsiteLive.Twitter/CachedTwitterTweetService.cs
new file mode 100644
index 0000000..200df02
--- /dev/null
+++ b/src/BirdsiteLive.Twitter/CachedTwitterTweetService.cs
@@ -0,0 +1,63 @@
+using System;
+using BirdsiteLive.Twitter.Models;
+using Microsoft.Extensions.Caching.Memory;
+
+namespace BirdsiteLive.Twitter
+{
+    public interface ICachedTwitterTweetsService : ITwitterTweetsService
+    {
+        void PurgeTweet(long statusId);
+    }
+
+    public class CachedTwitterTweetsService : ICachedTwitterTweetsService
+    {
+        private readonly ITwitterTweetsService _twitterService;
+
+        private MemoryCache _tweetCache = new MemoryCache(new MemoryCacheOptions()
+        {
+            SizeLimit = 5000
+        });
+        private MemoryCacheEntryOptions _cacheEntryOptions = new MemoryCacheEntryOptions()
+            .SetSize(1)//Size amount
+                       //Priority on removing when reaching size limit (memory pressure)
+            .SetPriority(CacheItemPriority.High)
+            // Keep in cache for this time, reset time if accessed.
+            // We set this lower than a user's in case they delete this Tweet for some reason; we don't need that cached.
+            .SetSlidingExpiration(TimeSpan.FromHours(2))
+            // Remove from cache after this time, regardless of sliding expiration
+            .SetAbsoluteExpiration(TimeSpan.FromDays(7));
+
+        #region Ctor
+        public CachedTwitterTweetsService(ITwitterTweetsService twitterService)
+        {
+            _twitterService = twitterService;
+        }
+
+        public ExtractedTweet[] GetTimeline(string username, int nberTweets, long fromTweetId = -1)
+        {
+            // This sounds like it'd be silly to cache; pass this directly to TwitterService.
+            // Theoretically this shouldn't be called more than once every 15 min anyway?
+            return _twitterService.GetTimeline(username, nberTweets, fromTweetId);
+        }
+
+        public ExtractedTweet GetTweet(long statusId)
+        {
+            if(!_tweetCache.TryGetValue(statusId, out ExtractedTweet tweet))
+            {
+                tweet = _twitterService.GetTweet(statusId);
+
+                // Unlike with the user cache, save the null value anyway to prevent (quicker) API exhaustion.
+                // It's incredibly unlikely that a tweet with this ID is going to magickally appear within 2 hours.
+                _tweetCache.Set(statusId, tweet, _cacheEntryOptions); 
+            }
+
+            return tweet;
+        }
+        #endregion
+
+        public void PurgeTweet(long statusId)
+        {
+            _tweetCache.Remove(statusId);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/BirdsiteLive.Twitter/CachedTwitterService.cs b/src/BirdsiteLive.Twitter/CachedTwitterUserService.cs
similarity index 100%
rename from src/BirdsiteLive.Twitter/CachedTwitterService.cs
rename to src/BirdsiteLive.Twitter/CachedTwitterUserService.cs
diff --git a/src/BirdsiteLive/BirdsiteLive.csproj b/src/BirdsiteLive/BirdsiteLive.csproj
index dd17829..08b6809 100644
--- a/src/BirdsiteLive/BirdsiteLive.csproj
+++ b/src/BirdsiteLive/BirdsiteLive.csproj
@@ -11,6 +11,7 @@
     <PackageReference Include="Lamar.Microsoft.DependencyInjection" Version="5.0.0" />
     <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.16.0" />
     <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.10.8" />
+    <PackageReference Include="Microsoft.VisualStudio.Web.BrowserLink" Version="2.2.0" />
     <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.3" />
   </ItemGroup>
 
diff --git a/src/BirdsiteLive/Controllers/UsersController.cs b/src/BirdsiteLive/Controllers/UsersController.cs
index a06b1e9..15e552e 100644
--- a/src/BirdsiteLive/Controllers/UsersController.cs
+++ b/src/BirdsiteLive/Controllers/UsersController.cs
@@ -143,6 +143,7 @@ namespace BirdsiteLive.Controllers
                         {
                             var succeeded = await _userService.FollowRequestedAsync(signature, r.Method, r.Path,
                                 r.QueryString.ToString(), RequestHeaders(r.Headers), activity as ActivityFollow, body);
+
                             if (succeeded) return Accepted();
                             else return Unauthorized();
                         }
diff --git a/src/BirdsiteLive/Startup.cs b/src/BirdsiteLive/Startup.cs
index 16c7ee4..034d414 100644
--- a/src/BirdsiteLive/Startup.cs
+++ b/src/BirdsiteLive/Startup.cs
@@ -91,6 +91,9 @@ namespace BirdsiteLive
             services.For<ITwitterUserService>().DecorateAllWith<CachedTwitterUserService>();
             services.For<ITwitterUserService>().Use<TwitterUserService>().Singleton();
 
+            services.For<ITwitterTweetsService>().DecorateAllWith<CachedTwitterTweetsService>();
+            services.For<ITwitterTweetsService>().Use<TwitterTweetsService>().Singleton();
+
             services.For<ITwitterAuthenticationInitializer>().Use<TwitterAuthenticationInitializer>().Singleton();
 
             services.Scan(_ =>
@@ -117,7 +120,8 @@ namespace BirdsiteLive
         {
             if (env.IsDevelopment())
             {
-                app.UseDeveloperExceptionPage();
+                app.UseDeveloperExceptionPage();
+                app.UseBrowserLink();
             }
             else
             {