From c371218672c006489ea629be68cf608ebb0a4a41 Mon Sep 17 00:00:00 2001
From: Nicolas Constant <github@nicolas-constant.com>
Date: Wed, 2 Feb 2022 23:25:03 -0500
Subject: [PATCH 1/2] prevent saturation of the user retrieval API

---
 .../Statistics/TwitterStatisticsHandler.cs               | 9 ++++++++-
 src/BirdsiteLive.Twitter/TwitterUserService.cs           | 9 ++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/BirdsiteLive.Twitter/Statistics/TwitterStatisticsHandler.cs b/src/BirdsiteLive.Twitter/Statistics/TwitterStatisticsHandler.cs
index 668be76..8063985 100644
--- a/src/BirdsiteLive.Twitter/Statistics/TwitterStatisticsHandler.cs
+++ b/src/BirdsiteLive.Twitter/Statistics/TwitterStatisticsHandler.cs
@@ -13,6 +13,8 @@ namespace BirdsiteLive.Statistics.Domain
         void CalledTweetApi();
         void CalledTimelineApi();
         ApiStatistics GetStatistics();
+
+        int GetCurrentUserCalls();
     }
 
     //Rate limits: https://developer.twitter.com/en/docs/twitter-api/v1/rate-limits
@@ -60,7 +62,12 @@ namespace BirdsiteLive.Statistics.Domain
             foreach (var old in oldSnapshots) _snapshots.TryRemove(old, out var data);
         }
 
-        public void CalledUserApi()  //GET users/show - 900/15mins
+        public int GetCurrentUserCalls()
+        {
+            return _userCalls;
+        }
+
+        public void CalledUserApi()  //GET users/show - 300/15mins
         {
             Interlocked.Increment(ref _userCalls);
         }
diff --git a/src/BirdsiteLive.Twitter/TwitterUserService.cs b/src/BirdsiteLive.Twitter/TwitterUserService.cs
index 6a27dc1..df6e5ad 100644
--- a/src/BirdsiteLive.Twitter/TwitterUserService.cs
+++ b/src/BirdsiteLive.Twitter/TwitterUserService.cs
@@ -32,6 +32,12 @@ namespace BirdsiteLive.Twitter
 
         public TwitterUser GetUser(string username)
         {
+            //Check if API is saturated 
+            var currentCalls = _statisticsHandler.GetCurrentUserCalls();
+            var maxCalls = _statisticsHandler.GetStatistics().UserCallsMax;
+            if (currentCalls > maxCalls) return null;
+
+            //Proceed to account retrieval
             _twitterAuthenticationInitializer.EnsureAuthenticationIsInitialized();
             ExceptionHandler.SwallowWebExceptions = false;
 
@@ -49,9 +55,6 @@ namespace BirdsiteLive.Twitter
             catch (Exception e)
             {
                 _logger.LogError(e, "Error retrieving user {Username}", username);
-
-                // TODO keep track of error, see where to remove user if too much errors
-
                 return null;
             }
 

From bf7baba789f592770532ca2dbd3b58877ffb1cb3 Mon Sep 17 00:00:00 2001
From: Nicolas Constant <github@nicolas-constant.com>
Date: Thu, 3 Feb 2022 01:06:32 -0500
Subject: [PATCH 2/2] added proper return on TooManyRequest case

---
 src/BirdsiteLive/Controllers/UsersController.cs  | 15 +++++++++++----
 src/BirdsiteLive/Views/Users/ApiSaturated.cshtml | 13 +++++++++++++
 2 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 src/BirdsiteLive/Views/Users/ApiSaturated.cshtml

diff --git a/src/BirdsiteLive/Controllers/UsersController.cs b/src/BirdsiteLive/Controllers/UsersController.cs
index 73be8b0..aa4f272 100644
--- a/src/BirdsiteLive/Controllers/UsersController.cs
+++ b/src/BirdsiteLive/Controllers/UsersController.cs
@@ -13,6 +13,7 @@ using BirdsiteLive.Common.Regexes;
 using BirdsiteLive.Common.Settings;
 using BirdsiteLive.Domain;
 using BirdsiteLive.Models;
+using BirdsiteLive.Statistics.Domain;
 using BirdsiteLive.Tools;
 using BirdsiteLive.Twitter;
 using BirdsiteLive.Twitter.Models;
@@ -32,9 +33,10 @@ namespace BirdsiteLive.Controllers
         private readonly IStatusService _statusService;
         private readonly InstanceSettings _instanceSettings;
         private readonly ILogger<UsersController> _logger;
+        private readonly ITwitterStatisticsHandler _twitterStatisticsHandler;
 
         #region Ctor
-        public UsersController(ITwitterUserService twitterUserService, IUserService userService, IStatusService statusService, InstanceSettings instanceSettings, ITwitterTweetsService twitterTweetService, ILogger<UsersController> logger)
+        public UsersController(ITwitterUserService twitterUserService, IUserService userService, IStatusService statusService, InstanceSettings instanceSettings, ITwitterTweetsService twitterTweetService, ILogger<UsersController> logger, ITwitterStatisticsHandler twitterStatisticsHandler)
         {
             _twitterUserService = twitterUserService;
             _userService = userService;
@@ -42,6 +44,7 @@ namespace BirdsiteLive.Controllers
             _instanceSettings = instanceSettings;
             _twitterTweetService = twitterTweetService;
             _logger = logger;
+            _twitterStatisticsHandler = twitterStatisticsHandler;
         }
         #endregion
 
@@ -72,12 +75,17 @@ namespace BirdsiteLive.Controllers
             if (!string.IsNullOrWhiteSpace(id) && UserRegexes.TwitterAccount.IsMatch(id) && id.Length <= 15)
                 user = _twitterUserService.GetUser(id);
 
+            var isSaturated = user == null
+                               && _twitterStatisticsHandler.GetCurrentUserCalls() >=
+                               _twitterStatisticsHandler.GetStatistics().UserCallsMax;
+
             var acceptHeaders = Request.Headers["Accept"];
             if (acceptHeaders.Any())
             {
                 var r = acceptHeaders.First();
                 if (r.Contains("application/activity+json"))
                 {
+                    if (user == null && isSaturated) return new ObjectResult("Too Many Requests") { StatusCode = 429 };
                     if (user == null) return NotFound();
                     var apUser = _userService.GetUser(user);
                     var jsonApUser = JsonConvert.SerializeObject(apUser);
@@ -85,8 +93,9 @@ namespace BirdsiteLive.Controllers
                 }
             }
 
+            if (user == null && isSaturated) return View("ApiSaturated");
             if (user == null) return View("UserNotFound");
-
+            
             var displayableUser = new DisplayTwitterUser
             {
                 Name = user.Name,
@@ -190,7 +199,5 @@ namespace BirdsiteLive.Controllers
             var jsonApUser = JsonConvert.SerializeObject(followers);
             return Content(jsonApUser, "application/activity+json; charset=utf-8");
         }
-
-      
     }
 }
\ No newline at end of file
diff --git a/src/BirdsiteLive/Views/Users/ApiSaturated.cshtml b/src/BirdsiteLive/Views/Users/ApiSaturated.cshtml
new file mode 100644
index 0000000..1f807aa
--- /dev/null
+++ b/src/BirdsiteLive/Views/Users/ApiSaturated.cshtml
@@ -0,0 +1,13 @@
+@using BirdsiteLive.Controllers;
+@{
+    ViewData["Title"] = "Api Saturated";
+}
+
+<div class="text-center">
+    <h1 class="display-4">429 Too Many Requests</h1>
+    <p>
+        <br />
+        The API is saturated.<br/>
+        Please consider using another instance.
+    </p>
+</div>
\ No newline at end of file