cleanup memory refs. switch to anglesharp lib

src/Icons/Icons.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="HtmlAgilityPack" Version="1.8.2" />
+    <PackageReference Include="AngleSharp" Version="0.9.9.2" />
     <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.6" />
   </ItemGroup>
 

src/Icons/Models/IconResult.cs

@@ -1,5 +1,4 @@
 using System;
-using HtmlAgilityPack;
 
 namespace Bit.Icons.Models
 {

src/Icons/Services/IconFetchingService.cs

@@ -6,35 +6,45 @@ using System.Net;
 using System.Net.Http;
 using System.Threading.Tasks;
 using Bit.Icons.Models;
-using HtmlAgilityPack;
+using AngleSharp.Parser.Html;
 
 namespace Bit.Icons.Services
 {
     public class IconFetchingService : IIconFetchingService
     {
-        private static HashSet<string> _iconRels = new HashSet<string> { "icon", "apple-touch-icon", "shortcut icon" };
+        private readonly HashSet<string> _iconRels =
-        private static HashSet<string> _iconExtensions = new HashSet<string> { ".ico", ".png", ".jpg", ".jpeg" };
+            new HashSet<string> { "icon", "apple-touch-icon", "shortcut icon" };
-        private static readonly HttpClient _httpClient = new HttpClient(new HttpClientHandler
+        private readonly HashSet<string> _iconExtensions =
+            new HashSet<string> { ".ico", ".png", ".jpg", ".jpeg" };
+
+        private readonly string _pngMediaType = "image/png";
+        private readonly byte[] _pngHeader = new byte[] { 137, 80, 78, 71 };
+
+        private readonly string _icoMediaType = "image/x-icon";
+        private readonly string _icoAltMediaType = "image/vnd.microsoft.icon";
+        private readonly byte[] _icoHeader = new byte[] { 00, 00, 01, 00 };
+
+        private readonly string _jpegMediaType = "image/jpeg";
+        private readonly byte[] _jpegHeader = new byte[] { 255, 216, 255 };
+
+        private readonly HashSet<string> _allowedMediaTypes;
+        private readonly HttpClient _httpClient;
+
+        public IconFetchingService()
+        {
+            _allowedMediaTypes = new HashSet<string>
             {
-            AllowAutoRedirect = false,
-            AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate,
-        });
-        private static string _pngMediaType = "image/png";
-        private static byte[] _pngHeader = new byte[] { 137, 80, 78, 71 };
-        private static string _icoMediaType = "image/x-icon";
-        private static string _icoAltMediaType = "image/vnd.microsoft.icon";
-        private static byte[] _icoHeader = new byte[] { 00, 00, 01, 00 };
-        private static string _jpegMediaType = "image/jpeg";
-        private static byte[] _jpegHeader = new byte[] { 255, 216, 255 };
-        private static readonly HashSet<string> _allowedMediaTypes = new HashSet<string>{
                 _pngMediaType,
                 _icoMediaType,
                 _icoAltMediaType,
                 _jpegMediaType
             };
 
-        public IconFetchingService()
+            _httpClient = new HttpClient(new HttpClientHandler
             {
+                AllowAutoRedirect = false,
+                AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate,
+            });
             _httpClient.Timeout = TimeSpan.FromSeconds(20);
         }
 
@@ -44,10 +54,12 @@ namespace Bit.Icons.Services
             var response = await GetAndFollowAsync(uri, 2);
             if(response == null || !response.IsSuccessStatusCode)
             {
+                Cleanup(response);
                 uri = new Uri($"http://{domain}");
                 response = await GetAndFollowAsync(uri, 2);
                 if(response == null || !response.IsSuccessStatusCode)
                 {
+                    Cleanup(response);
                     uri = new Uri($"https://www.{domain}");
                     response = await GetAndFollowAsync(uri, 2);
                 }
@@ -55,38 +67,23 @@ namespace Bit.Icons.Services
 
             if(response?.Content == null || !response.IsSuccessStatusCode)
             {
+                Cleanup(response);
                 return null;
             }
 
-            uri = response.RequestMessage.RequestUri;
+            var parser = new HtmlParser();
-            var doc = new HtmlDocument();
+            using(response)
-
             using(var htmlStream = await response.Content.ReadAsStreamAsync())
+            using(var document = await parser.ParseAsync(htmlStream))
             {
-                if(htmlStream == null)
+                uri = response.RequestMessage.RequestUri;
+                if(document.DocumentElement == null)
                 {
-                    doc = null;
                     return null;
                 }
 
-                try
-                {
-                    doc.Load(htmlStream);
-                    if(doc.DocumentNode == null)
-                    {
-                        doc = null;
-                        return null;
-                    }
-                }
-                catch
-                {
-                    doc = null;
-                    return null;
-                }
-            }
-
                 var baseUrl = "/";
-            var baseUrlNode = doc.DocumentNode.SelectSingleNode(@"//head/base[@href]");
+                var baseUrlNode = document.QuerySelector("head base[href]");
                 if(baseUrlNode != null)
                 {
                     var hrefAttr = baseUrlNode.Attributes["href"];
@@ -100,8 +97,7 @@ namespace Bit.Icons.Services
                 }
 
                 var icons = new List<IconResult>();
-            var links = doc.DocumentNode.SelectNodes(@"//head/link[@href]");
+                var links = document.QuerySelectorAll("head link[href]");
-            doc = null;
                 if(links != null)
                 {
                     foreach(var link in links.Take(40))
@@ -188,17 +184,21 @@ namespace Bit.Icons.Services
 
                 return icons.Where(i => i.Icon != null).OrderBy(i => i.Priority).First();
             }
+        }
 
         private async Task<IconResult> GetIconAsync(Uri uri)
         {
-            var response = await GetAndFollowAsync(uri, 2);
+            using(var response = await GetAndFollowAsync(uri, 2))
+            {
                 if(response?.Content?.Headers == null || !response.IsSuccessStatusCode)
                 {
+                    response?.Content?.Dispose();
                     return null;
                 }
 
                 var format = response.Content.Headers?.ContentType?.MediaType;
                 var bytes = await response.Content.ReadAsByteArrayAsync();
+                response.Content.Dispose();
                 if(format == null || !_allowedMediaTypes.Contains(format))
                 {
                     if(HeaderMatch(bytes, _icoHeader))
@@ -221,6 +221,7 @@ namespace Bit.Icons.Services
 
                 return new IconResult(uri, bytes, format);
             }
+        }
 
         private async Task<HttpResponseMessage> GetAndFollowAsync(Uri uri, int maxRedirectCount)
         {
@@ -234,11 +235,10 @@ namespace Bit.Icons.Services
 
         private async Task<HttpResponseMessage> GetAsync(Uri uri)
         {
-            var message = new HttpRequestMessage
+            using(var message = new HttpRequestMessage())
             {
-                RequestUri = uri,
+                message.RequestUri = uri;
-                Method = HttpMethod.Get
+                message.Method = HttpMethod.Get;
-            };
 
                 // Let's add some headers to look like we're coming from a web browser request. Some websites
                 // will block our request without these.
@@ -259,6 +259,7 @@ namespace Bit.Icons.Services
                     return null;
                 }
             }
+        }
 
         private async Task<HttpResponseMessage> FollowRedirectsAsync(HttpResponseMessage response,
             int maxFollowCount, int followCount = 0)
@@ -272,14 +273,15 @@ namespace Bit.Icons.Services
                 response.StatusCode == HttpStatusCode.MovedPermanently ||
                 response.StatusCode == HttpStatusCode.RedirectKeepVerb ||
                 response.StatusCode == HttpStatusCode.SeeOther) ||
-                !response.Headers.Contains("Location"))
+                response.Headers.Location == null)
             {
+                Cleanup(response);
                 return null;
             }
 
-            var locationHeader = response.Headers.GetValues("Location").FirstOrDefault();
+            if(response.Headers.Location != null)
-            if(!string.IsNullOrWhiteSpace(locationHeader))
             {
+                var locationHeader = response.Headers.Location.ToString();
                 if(!Uri.TryCreate(locationHeader, UriKind.Absolute, out Uri location))
                 {
                     if(Uri.TryCreate(locationHeader, UriKind.Relative, out Uri relLocation))
@@ -293,12 +295,17 @@ namespace Bit.Icons.Services
                     }
                 }
 
+                Cleanup(response);
                 var newResponse = await GetAsync(location);
                 if(newResponse != null)
                 {
                     var redirectedResponse = await FollowRedirectsAsync(newResponse, maxFollowCount, followCount++);
                     if(redirectedResponse != null)
                     {
+                        if(redirectedResponse != newResponse)
+                        {
+                            Cleanup(newResponse);
+                        }
                         return redirectedResponse;
                     }
                 }
@@ -324,5 +331,11 @@ namespace Bit.Icons.Services
             }
             return new Uri(url);
         }
+
+        private void Cleanup(IDisposable obj)
+        {
+            obj?.Dispose();
+            obj = null;
+        }
     }
 }