Using DownloadResult and calculating MD5

Author: StanleyGoldman

src/GitHub.Api/IO/FileSystem.cs

@@ -34,6 +34,12 @@ public bool FileExists(string filename)
             return File.Exists(filename);
         }
 
+        public long FileLength(string path)
+        {
+            var fileInfo = new FileInfo(path);
+            return fileInfo.Length;
+        }
+
         public IEnumerable<string> GetDirectories(string path)
         {
             return Directory.GetDirectories(path);
@@ -206,5 +212,10 @@ public Stream OpenRead(string path)
         {
             return File.OpenRead(path);
         }
+
+        public Stream OpenWrite(string path, FileMode mode)
+        {
+            return new FileStream(path, mode);
+        }
     }
 }

src/GitHub.Api/IO/IFileSystem.cs

@@ -7,6 +7,7 @@ namespace GitHub.Unity
     public interface IFileSystem
     {
         bool FileExists(string path);
+        long FileLength(string path);
         string Combine(string path1, string path2);
         string Combine(string path1, string path2, string path3);
         string GetFullPath(string path);
@@ -37,6 +38,7 @@ public interface IFileSystem
         string ReadAllText(string path);
         string ReadAllText(string path, Encoding encoding);
         Stream OpenRead(string path);
+        Stream OpenWrite(string path, FileMode mode);
         string[] ReadAllLines(string path);
         char DirectorySeparatorChar { get; }
         bool ExistingPathIsDirectory(string path);

src/GitHub.Api/Tasks/DownloadTask.cs

@@ -76,7 +76,13 @@ public static bool Copy(Stream source, Stream destination, int chunkSize, long t
 
     public class DownloadResult
     {
+        public bool Success { get; set; }
 
+        public string Url { get; set; }
+
+        public string Destination { get; set; }
+
+        public string MD5Sum { get; set; }
     }
 
     public static class WebRequestExtensions
@@ -96,32 +102,37 @@ public static WebResponse GetResponseWithoutException(this WebRequest request)
 
     class DownloadTask: TaskBase<DownloadResult>
     {
+        private IFileSystem fileSystem;
         private long bytes;
         private WebRequest webRequest;
         private bool restarted;
 
         public float Progress { get; set; }
 
-        public DownloadTask(CancellationToken token, string url, string destination)
+        public DownloadTask(CancellationToken token, IFileSystem fileSystem, string url, string destination)
             : base(token)
         {
+            this.fileSystem = fileSystem;
             Url = url;
             Destination = destination;
             Name = "DownloadTask";
         }
 
         protected override DownloadResult RunWithReturn(bool success)
         {
-            DownloadResult result = base.RunWithReturn(success);
-
+            base.RunWithReturn(success);
+            
             RaiseOnStart();
 
+            var downloadResult = new DownloadResult {
+                Url = Url,
+                Destination = Destination
+            };
+
             try
             {
-                Logger.Trace("Downloading");
-                RunDownload();
-
-                Logger.Trace("Downloaded");
+                downloadResult.Success = Download();
+                downloadResult.MD5Sum = fileSystem.CalculateMD5(Destination);
             }
             catch (Exception ex)
             {
@@ -131,30 +142,31 @@ protected override DownloadResult RunWithReturn(bool success)
             }
             finally
             {
-                RaiseOnEnd(result);
+                RaiseOnEnd(downloadResult);
             }
 
-            return result;
+            return downloadResult;
         }
 
         protected virtual void UpdateProgress(float progress)
         {
             Progress = progress;
         }
 
-        public bool RunDownload()
+        public bool Download()
         {
-            var fileInfo = new FileInfo(Destination);
-            if (fileInfo.Exists)
+            FileInfo fileInfo = new FileInfo(Destination);
+            if (fileSystem.FileExists(Destination))
             {
-                if (fileInfo.Length > 0)
+                var fileLength = fileSystem.FileLength(Destination);
+                if (fileLength > 0)
                 {
                     bytes = fileInfo.Length;
                     restarted = true;
                 }
-                else if (fileInfo.Length == 0)
+                else if (fileLength == 0)
                 {
-                    fileInfo.Delete();
+                    fileSystem.FileDelete(Destination);
                 }
             }
 
@@ -209,7 +221,7 @@ public bool RunDownload()
 
                 using (var responseStream = webResponse.GetResponseStream())
                 {
-                    using (Stream destinationStream = new FileStream(Destination, FileMode.Append))
+                    using (var destinationStream = fileSystem.OpenWrite(Destination, FileMode.Append))
                     {
                         if (Token.IsCancellationRequested)
                             return false;

src/tests/IntegrationTests/Download/DownloadTaskTests.cs

@@ -25,14 +25,13 @@ public async Task TestDownloadTask()
             var downloadPath = TestBasePath.Combine("5MB.zip");
             var downloadHalfPath = TestBasePath.Combine("5MB-split.zip");
 
-            var downloadTask = new DownloadTask(CancellationToken.None, TestDownload, downloadPath);
-            await downloadTask.StartAwait();
+            var downloadTask = new DownloadTask(CancellationToken.None, fileSystem, TestDownload, downloadPath);
+            var downloadResult = await downloadTask.StartAwait();
 
             var downloadPathBytes = fileSystem.ReadAllBytes(downloadPath);
             Logger.Trace("File size {0} bytes", downloadPathBytes.Length);
 
-            var computedHash = fileSystem.CalculateMD5(downloadPath);
-            computedHash.Should().Be(TestDownloadMD5.ToUpperInvariant());
+            downloadResult.MD5Sum.Should().Be(TestDownloadMD5.ToUpperInvariant());
 
             var random = new Random();
             var takeCount = random.Next(downloadPathBytes.Length);
@@ -42,14 +41,13 @@ public async Task TestDownloadTask()
             var cutDownloadPathBytes = downloadPathBytes.Take(takeCount).ToArray();
             fileSystem.WriteAllBytes(downloadHalfPath, cutDownloadPathBytes);
 
-            downloadTask = new DownloadTask(CancellationToken.None, TestDownload, downloadHalfPath);
-            await downloadTask.StartAwait();
+            downloadTask = new DownloadTask(CancellationToken.None, fileSystem, TestDownload, downloadHalfPath);
+            downloadResult = await downloadTask.StartAwait();
 
             var downloadHalfPathBytes = fileSystem.ReadAllBytes(downloadHalfPath);
             Logger.Trace("File size {0} Bytes", downloadHalfPathBytes.Length);
 
-            computedHash = fileSystem.CalculateMD5(downloadHalfPath);
-            computedHash.Should().Be(TestDownloadMD5.ToUpperInvariant());
+            downloadResult.MD5Sum.Should().Be(TestDownloadMD5.ToUpperInvariant());
         }
     }
 }