Core: Use an HttpClient singleton to prevent unnecessary disposal

DailyDesktop.Core/Configuration/IPublicPathConfiguration.cs

@@ -26,7 +26,7 @@ public interface IPublicPathConfiguration : IReadOnlyPathConfiguration
         /// The serialization directory (e.g. for the <see cref="TaskConfiguration"/> JSON).
         /// </summary>
         new string SerializationDir { get; set; }
-        
+
         /// <summary>
         /// Asynchronously sets the assembly directory (e.g. for the task executable).
         /// </summary>

DailyDesktop.Core/Configuration/PathConfiguration.cs

@@ -81,34 +81,34 @@ public string SerializationDir
         /// <inheritdoc/>
         public async Task SetAssemblyDirAsync(string assemblyDir, CancellationToken cancellationToken)
         {
-                if (this.assemblyDir == assemblyDir)
-                    return;
+            if (this.assemblyDir == assemblyDir)
+                return;
 
-                Directory.CreateDirectory(assemblyDir);
-                this.assemblyDir = assemblyDir;
-                await UpdateAsync(cancellationToken);
+            Directory.CreateDirectory(assemblyDir);
+            this.assemblyDir = assemblyDir;
+            await UpdateAsync(cancellationToken);
         }
 
         /// <inheritdoc/>
         public async Task SetProvidersDirAsync(string providersDir, CancellationToken cancellationToken)
         {
-                if (this.providersDir == providersDir)
-                    return;
+            if (this.providersDir == providersDir)
+                return;
 
-                Directory.CreateDirectory(providersDir);
-                this.providersDir = providersDir;
-                await UpdateAsync(cancellationToken);
+            Directory.CreateDirectory(providersDir);
+            this.providersDir = providersDir;
+            await UpdateAsync(cancellationToken);
         }
 
         /// <inheritdoc/>
         public async Task SetSerializationDirAsync(string serializationDir, CancellationToken cancellationToken)
         {
-                if (this.serializationDir == serializationDir)
-                    return;
+            if (this.serializationDir == serializationDir)
+                return;
 
-                Directory.CreateDirectory(serializationDir);
-                this.serializationDir = serializationDir;
-                await UpdateAsync(cancellationToken);
+            Directory.CreateDirectory(serializationDir);
+            this.serializationDir = serializationDir;
+            await UpdateAsync(cancellationToken);
         }
 
         /// <inheritdoc/>

DailyDesktop.Core/Configuration/TaskConfiguration.cs

@@ -101,7 +101,7 @@ public int BlurStrength
                 Update();
             }
         }
-        
+
         /// <inheritdoc/>
         public async Task SetDllAsync(string dll, CancellationToken cancellationToken)
         {
@@ -111,7 +111,7 @@ public async Task SetDllAsync(string dll, CancellationToken cancellationToken)
             this.dll = dll;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetIsEnabledAsync(bool isEnabled, CancellationToken cancellationToken)
         {
@@ -121,7 +121,7 @@ public async Task SetIsEnabledAsync(bool isEnabled, CancellationToken cancellati
             this.isEnabled = isEnabled;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetUpdateTimeAsync(DateTime updateTime, CancellationToken cancellationToken)
         {
@@ -131,7 +131,7 @@ public async Task SetUpdateTimeAsync(DateTime updateTime, CancellationToken canc
             this.updateTime = updateTime;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetDoResizeAsync(bool doResize, CancellationToken cancellationToken)
         {
@@ -151,7 +151,7 @@ public async Task SetDoBlurredFitAsync(bool doBlurredFit, CancellationToken canc
             this.doBlurredFit = doBlurredFit;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetBlurStrengthAsync(int blurStrength, CancellationToken cancellationToken)
         {

DailyDesktop.Core/Configuration/WallpaperConfiguration.cs

@@ -165,7 +165,7 @@ public async Task SetImageUriAsync(string imageUri, CancellationToken cancellati
             this.imageUri = imageUri;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetAuthorAsync(string? author, CancellationToken cancellationToken)
         {
@@ -175,7 +175,7 @@ public async Task SetAuthorAsync(string? author, CancellationToken cancellationT
             this.author = author;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetAuthorUriAsync(string? authorUri, CancellationToken cancellationToken)
         {
@@ -185,7 +185,7 @@ public async Task SetAuthorUriAsync(string? authorUri, CancellationToken cancell
             this.authorUri = authorUri;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetTitleAsync(string? title, CancellationToken cancellationToken)
         {
@@ -195,7 +195,7 @@ public async Task SetTitleAsync(string? title, CancellationToken cancellationTok
             this.title = title;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetTitleUriAsync(string? titleUri, CancellationToken cancellationToken)
         {
@@ -205,7 +205,7 @@ public async Task SetTitleUriAsync(string? titleUri, CancellationToken cancellat
             this.titleUri = titleUri;
             await UpdateAsync(cancellationToken);
         }
-        
+
         /// <inheritdoc/>
         public async Task SetDescriptionAsync(string? description, CancellationToken cancellationToken)
         {

DailyDesktop.Core/Providers/IProvider.cs

@@ -3,9 +3,11 @@
 
 using System;
 using System.Net.Http;
+using System.Net.Http.Headers;
 using System.Threading;
 using System.Threading.Tasks;
 using DailyDesktop.Core.Configuration;
+using DailyDesktop.Core.Util;
 
 namespace DailyDesktop.Core.Providers
 {
@@ -36,10 +38,10 @@ public interface IProvider
         /// Configures an <see cref="HttpClient"/> to be used for the
         /// <see cref="WallpaperConfiguration.ImageUri"/> returned by
         /// <see cref="ConfigureWallpaperAsync"/>. Used by
-        /// <see cref="IProviderExtensions.CreateHttpClient(IProvider)"/>.
+        /// <see cref="IProviderExtensions.ConfigureWallpaperAsync(IProvider, IPublicWallpaperConfiguration, CancellationToken)"/>.
         /// </summary>
-        /// <param name="client">The <see cref="HttpClient"/> to configure.</param>
-        void ConfigureHttpClient(HttpClient client) { }
+        /// <param name="headers">The <see cref="HttpRequestHeaders"/> to configure.</param>
+        void ConfigureHttpRequestHeaders(HttpRequestHeaders headers) { }
 
         /// <summary>
         /// Asynchronously onfigures a <see cref="IPublicWallpaperConfiguration"/> using a given
@@ -73,32 +75,17 @@ static IProvider Instantiate(Type type)
     public static class IProviderExtensions
     {
         /// <summary>
-        /// Creates an <see cref="HttpClient"/> with a proper User-Agent header and
-        /// configured by <see cref="IProvider.ConfigureHttpClient(HttpClient)"/>.
-        /// </summary>
-        /// <param name="provider">The <see cref="IProvider"/> configuring the returned <see cref="HttpClient"/>.</param>
-        /// <returns>The pre-configured <see cref="HttpClient"/>.</returns>
-        public static HttpClient CreateHttpClient(this IProvider provider)
-        {
-            var client = new HttpClient();
-            client.DefaultRequestHeaders.Add("User-Agent", "daily-desktop/0.0 (https://github.com/goodtrailer/daily-desktop)");
-            provider.ConfigureHttpClient(client);
-
-            return client;
-        }
-
-        /// <summary>
-        /// Asynchronously configures a <see cref="WallpaperConfiguration"/> using a pre-configured
-        /// <see cref="HttpClient"/> created by <see cref="CreateHttpClient(IProvider)"/>.
+        /// Asynchronously configures a <see cref="WallpaperConfiguration"/>.
         /// </summary>
         /// <param name="provider">The <see cref="IProvider"/> configuring the <see cref="WallpaperConfiguration"/>.</param>
         /// <param name="wallpaperConfig">The <see cref="IPublicWallpaperConfiguration"/> to configure.</param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
         /// <returns>The up-to-date <see cref="WallpaperConfiguration"/>.</returns>
         public static async Task ConfigureWallpaperAsync(this IProvider provider, IPublicWallpaperConfiguration wallpaperConfig, CancellationToken cancellationToken)
         {
-            using (var client = provider.CreateHttpClient())
-                await provider.ConfigureWallpaperAsync(client, wallpaperConfig, cancellationToken);
+            HttpUtils.ResetRequestHeaders();
+            provider.ConfigureHttpRequestHeaders(HttpUtils.Client.DefaultRequestHeaders);
+            await provider.ConfigureWallpaperAsync(HttpUtils.Client, wallpaperConfig, cancellationToken);
 
             wallpaperConfig.NullifyWhitespace();
         }

DailyDesktop.Core/Providers/ProviderStore.cs

@@ -18,7 +18,7 @@ namespace DailyDesktop.Core.Providers
     public class ProviderStore
     {
         private const string PROVIDERS_SEARCH_PATTERN = "*.dll";
-        
+
         /// <summary>
         /// Dictionary of <see cref="IProvider"/> <see cref="Type"/>s
         /// added through <see cref="Scan"/> and <see cref="Add"/>.
@@ -46,7 +46,7 @@ public async Task<Type> Add(string dllPath, CancellationToken cancellationToken)
                 return Providers[dllPath];
 
             var assembly = Assembly.Load(await File.ReadAllBytesAsync(dllPath, cancellationToken));
-            
+
             foreach (var type in assembly.GetTypes())
             {
                 bool isPublic = type.IsPublic;

DailyDesktop.Core/Util/AsyncUtils.cs

@@ -6,7 +6,7 @@
 namespace DailyDesktop.Core.Util
 {
     /// <summary>
-    /// Utility functions for async logic.
+    /// Utilities for async logic.
     /// </summary>
     public static class AsyncUtils
     {

DailyDesktop.Core/Util/HttpUtils.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Alden Wu <aldenwu0@gmail.com>. Licensed under the MIT Licence.
+// See the LICENSE file in the repository root for full licence text.
+
+using System.Net.Http;
+
+namespace DailyDesktop.Core.Util
+{
+    /// <summary>
+    /// Utilities for Http logic.
+    /// </summary>
+    public static class HttpUtils
+    {
+        /// <summary>
+        /// An <see cref="HttpClient"/> singleton for use everywhere.
+        /// </summary>
+        public static HttpClient Client => client ??= new HttpClient();
+        private static HttpClient? client;
+
+        /// <summary>
+        /// Resets <see cref="Client"/>'s request headers, which includes adding
+        /// a user agent header that points to Daily Desktop.
+        /// </summary>
+        public static void ResetRequestHeaders()
+        {
+            Client.DefaultRequestHeaders.Clear();
+            Client.DefaultRequestHeaders.Add("User-Agent", "daily-desktop/0.0 (https://github.com/goodtrailer/daily-desktop)");
+        }
+    }
+}

DailyDesktop.Desktop/MainForm.cs

@@ -138,6 +138,8 @@ private void updateProviderInfo()
         {
             providerDescriptionLabel.Text = core.CurrentProvider?.Description ?? null_description;
             providerSourceLinkLabel.Text = core.CurrentProvider?.SourceUri ?? null_text;
+            providerSourceLinkLabel.Links[0].Enabled = Uri.TryCreate(providerSourceLinkLabel.Text, UriKind.Absolute, out _);
+            providerSourceLinkLabel.TabStop = wallpaperAuthorLinkLabel.Links[0].Enabled;
         }
 
         private async Task repopulateProviderComboBox()
@@ -225,28 +227,28 @@ private async void optionsResizeCheckBox_CheckedChanged(object? _, EventArgs e)
         private void updateWallpaperInfo_Impl(bool isDeserializationSuccessful)
         {
             if (isDeserializationSuccessful)
-                {
-                    wallpaperUpdatedLabel.Text = $"{fetched_text} {wallpaperConfig.Date.ToString("dddd, MMMM d") ?? null_text}";
-                    wallpaperTitleLinkLabel.Text = wallpaperConfig.Title ?? null_text;
-                    wallpaperAuthorLinkLabel.Text = wallpaperConfig.Author ?? null_text;
-                    wallpaperDescriptionRichTextBox.Text = Regex.Replace(wallpaperConfig.Description ?? null_description, "(?<=[^\r])\n", "\r\n");
+            {
+                wallpaperUpdatedLabel.Text = $"{fetched_text} {wallpaperConfig.Date.ToString("dddd, MMMM d") ?? null_text}";
+                wallpaperTitleLinkLabel.Text = wallpaperConfig.Title ?? null_text;
+                wallpaperAuthorLinkLabel.Text = wallpaperConfig.Author ?? null_text;
+                wallpaperDescriptionRichTextBox.Text = Regex.Replace(wallpaperConfig.Description ?? null_description, "(?<=[^\r])\n", "\r\n");
 
-                    wallpaperTitleLinkLabel.Links[0].Enabled = Uri.TryCreate(wallpaperConfig.TitleUri, UriKind.Absolute, out _);
-                    wallpaperTitleLinkLabel.TabStop = wallpaperTitleLinkLabel.Links[0].Enabled;
+                wallpaperTitleLinkLabel.Links[0].Enabled = Uri.TryCreate(wallpaperConfig.TitleUri, UriKind.Absolute, out _);
+                wallpaperTitleLinkLabel.TabStop = wallpaperTitleLinkLabel.Links[0].Enabled;
 
-                    wallpaperAuthorLinkLabel.Links[0].Enabled = Uri.TryCreate(wallpaperConfig.AuthorUri, UriKind.Absolute, out _);
-                    wallpaperAuthorLinkLabel.TabStop = wallpaperAuthorLinkLabel.Links[0].Enabled;
-                }
-                else
-                {
-                    wallpaperUpdatedLabel.Text = $"{fetched_text} {null_text}";
-                    wallpaperTitleLinkLabel.Text = null_text;
-                    wallpaperAuthorLinkLabel.Text = null_text;
-                    wallpaperDescriptionRichTextBox.Text = null_description;
+                wallpaperAuthorLinkLabel.Links[0].Enabled = Uri.TryCreate(wallpaperConfig.AuthorUri, UriKind.Absolute, out _);
+                wallpaperAuthorLinkLabel.TabStop = wallpaperAuthorLinkLabel.Links[0].Enabled;
+            }
+            else
+            {
+                wallpaperUpdatedLabel.Text = $"{fetched_text} {null_text}";
+                wallpaperTitleLinkLabel.Text = null_text;
+                wallpaperAuthorLinkLabel.Text = null_text;
+                wallpaperDescriptionRichTextBox.Text = null_description;
 
-                    wallpaperTitleLinkLabel.Links[0].Enabled = false;
-                    wallpaperAuthorLinkLabel.Links[0].Enabled = false;
-                }
+                wallpaperTitleLinkLabel.Links[0].Enabled = false;
+                wallpaperAuthorLinkLabel.Links[0].Enabled = false;
+            }
         }
 
         private void stateBackgroundWorker_DoWork(object? _, EventArgs e)

DailyDesktop.Providers.Bing/BingProvider.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using DailyDesktop.Core.Configuration;
 using DailyDesktop.Core.Providers;
-using DailyDesktop.Core.Util;
 
 namespace DailyDesktop.Providers.Bing
 {

DailyDesktop.Providers.Pixiv/PixivProvider.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Net;
 using System.Net.Http;
+using System.Net.Http.Headers;
 using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
@@ -26,9 +27,9 @@ public class PixivProvider : IProvider
             "Using blurred-fit mode is highly recommended due to the large variety of aspect ratios of illustrations found on pixiv.";
         public string SourceUri => "https://www.pixiv.net/ranking.php?content=illust";
 
-        public void ConfigureHttpClient(HttpClient client)
+        public void ConfigureHttpRequestHeaders(HttpRequestHeaders headers)
         {
-            client.DefaultRequestHeaders.Referrer = new Uri("https://www.pixiv.net");
+            headers.Referrer = new Uri("https://www.pixiv.net");
         }
 
         public async Task ConfigureWallpaperAsync(HttpClient client, IPublicWallpaperConfiguration wallpaperConfig, CancellationToken cancellationToken)

DailyDesktop.Task/Program.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Alden Wu <aldenwu0@gmail.com>. Licensed under the MIT Licence.
 // See the LICENSE file in the repository root for full licence text.
 
-using System;
 using System.CommandLine;
 using System.CommandLine.Invocation;
 using System.Drawing;
@@ -76,12 +75,10 @@ private static async Task<string> downloadWallpaper(IProvider provider, string j
             await provider.ConfigureWallpaperAsync(wallpaperConfig, cancellationToken);
             await wallpaperConfig.TrySerializeAsync(cancellationToken);
 
-            using (var client = provider.CreateHttpClient())
-            {
-                var stream = await client.GetStreamAsync(wallpaperConfig.ImageUri, cancellationToken);
-                using (var fstream = new FileStream(imagePath, FileMode.OpenOrCreate))
-                    await stream.CopyToAsync(fstream, cancellationToken);
-            }
+            provider.ConfigureHttpRequestHeaders(HttpUtils.Client.DefaultRequestHeaders);
+            var stream = await HttpUtils.Client.GetStreamAsync(wallpaperConfig.ImageUri, cancellationToken);
+            using (var fstream = new FileStream(imagePath, FileMode.OpenOrCreate))
+                await stream.CopyToAsync(fstream, cancellationToken);
 
             return imagePath;
         }