From 534a444ab3c60e3a209132de8046c3e6e5db5d15 Mon Sep 17 00:00:00 2001
From: Albie <albion@dragonfruit.network>
Date: Mon, 11 Jan 2021 10:39:13 +0000
Subject: [PATCH] add file download progress reporting

---
 .../Files/FileDownloadTests.cs                | 23 ++++++++++++++-----
 DragonFruit.Common.Data/ApiClient.cs          | 15 ++++++++----
 DragonFruit.Common.Data/ApiFileRequest.cs     | 17 ++++++++++++--
 3 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/DragonFruit.Common.Data.Tests/Files/FileDownloadTests.cs b/DragonFruit.Common.Data.Tests/Files/FileDownloadTests.cs
index aa174f7..8f8690d 100644
--- a/DragonFruit.Common.Data.Tests/Files/FileDownloadTests.cs
+++ b/DragonFruit.Common.Data.Tests/Files/FileDownloadTests.cs
@@ -1,6 +1,7 @@
 // DragonFruit.Common Copyright 2020 DragonFruit Network
 // Licensed under the MIT License. Please refer to the LICENSE file at the root of this project for details
 
+using System;
 using System.IO;
 using DragonFruit.Common.Data.Basic;
 using NUnit.Framework;
@@ -10,19 +11,29 @@ namespace DragonFruit.Common.Data.Tests.Files
     [TestFixture]
     public class FileDownloadTests : ApiTest
     {
-        [TestCase]
-        public void FileDownloadTest()
+        [TestCase("https://github.com/ppy/osu/archive/2020.1121.0.zip", 19018589)]
+        public void FileDownloadTest(string path, long expectedFileSize)
         {
-            var request = new BasicApiFileRequest("https://github.com/ppy/osu/archive/2020.1121.0.zip", Path.GetTempPath());
+            var request = new BasicApiFileRequest(path, Path.GetTempPath());
 
-            Assert.IsFalse(File.Exists(request.Destination));
+            if (File.Exists(request.Destination))
+            {
+                try
+                {
+                    File.Delete(request.Destination);
+                }
+                catch
+                {
+                    Assert.Inconclusive("Failed to remove file needed for test");
+                }
+            }
 
             try
             {
-                Client.Perform(request);
+                Client.Perform(request, (progress, total) => TestContext.Out.WriteLine($"Progress: {progress:n0}/{total:n0} ({Convert.ToSingle(progress) / Convert.ToSingle(total):F2}%)"));
 
                 Assert.IsTrue(File.Exists(request.Destination));
-                Assert.IsTrue(new FileInfo(request.Destination).Length > 5000);
+                Assert.GreaterOrEqual(new FileInfo(request.Destination).Length, expectedFileSize);
             }
             finally
             {
diff --git a/DragonFruit.Common.Data/ApiClient.cs b/DragonFruit.Common.Data/ApiClient.cs
index 2f0d65a..8153145 100644
--- a/DragonFruit.Common.Data/ApiClient.cs
+++ b/DragonFruit.Common.Data/ApiClient.cs
@@ -244,7 +244,7 @@ public virtual T Perform<T>(HttpRequestMessage request, CancellationToken token
         /// Download a file with an <see cref="ApiRequest"/>.
         /// Bypasses <see cref="ValidateAndProcess{T}"/>
         /// </summary>
-        public virtual void Perform(ApiFileRequest request, CancellationToken token = default)
+        public virtual void Perform(ApiFileRequest request, Action<long, long?> progressUpdated = null, CancellationToken token = default)
         {
             //check request data is valid
             ValidateRequest(request);
@@ -256,18 +256,25 @@ public virtual void Perform(ApiFileRequest request, CancellationToken token = de
 
             HttpResponseMessage CopyProcess(HttpResponseMessage response)
             {
-                //validate
+                // validate
                 response.EnsureSuccessStatusCode();
 
                 // create a new filestream and copy all data into
                 using var stream = File.Open(request.Destination, request.FileCreationMode);
-
 #if NET5_0
                 using var networkStream = response.Content.ReadAsStreamAsync(token).Result;
 #else
                 using var networkStream = response.Content.ReadAsStreamAsync().Result;
 #endif
-                networkStream.CopyTo(stream);
+                // create a buffer for progress reporting
+                var buffer = new byte[request.BufferSize];
+                int count;
+
+                while ((count = networkStream.Read(buffer, 0, buffer.Length)) > 0)
+                {
+                    stream.Write(buffer, 0, count);
+                    progressUpdated?.Invoke(stream.Length, response.Content.Headers.ContentLength);
+                }
 
                 // flush and return
                 stream.Flush();
diff --git a/DragonFruit.Common.Data/ApiFileRequest.cs b/DragonFruit.Common.Data/ApiFileRequest.cs
index bfa15fc..3743b80 100644
--- a/DragonFruit.Common.Data/ApiFileRequest.cs
+++ b/DragonFruit.Common.Data/ApiFileRequest.cs
@@ -7,10 +7,23 @@ namespace DragonFruit.Common.Data
 {
     public abstract class ApiFileRequest : ApiRequest
     {
-        protected override Methods Method => Methods.Get;
-
+        /// <summary>
+        /// The location, on the disk, to put the resultant file
+        /// </summary>
         public abstract string Destination { get; }
 
+        /// <summary>
+        /// The mode of file creation
+        /// </summary>
         public virtual FileMode FileCreationMode => FileMode.Create;
+
+        /// <summary>
+        /// Length, in bytes, of the buffer used for copying data from the network stream to the file.
+        /// Defaults to 32kb
+        /// </summary>
+        /// <remarks>
+        /// This should be less than 85KiB (87040 bytes) to avoid potential memory leaks
+        /// </remarks>
+        public virtual int BufferSize => 32 * 1024;
     }
 }