optimize for readability

MareSynchronosServer/MareSynchronosStaticFilesServer/CachedFileProvider.cs

@@ -24,78 +24,60 @@ public class CachedFileProvider
         _basePath = configuration.GetValue<string>(nameof(StaticFilesServerConfiguration.CacheDirectory));
     }
 
+    private async Task DownloadTask(string hash, string auth)
+    {
+        // download file from remote
+        var downloadUrl = new Uri(_remoteCacheSourceUri, hash);
+        _logger.LogInformation("Did not find {hash}, downloading from {server}", hash, downloadUrl);
+        using var client = new HttpClient();
+        client.DefaultRequestHeaders.Add("Authorization", auth);
+        var response = await client.GetAsync(downloadUrl, HttpCompletionOption.ResponseHeadersRead).ConfigureAwait(false);
+
+        try
+        {
+            response.EnsureSuccessStatusCode();
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(ex, "Failed to download {url}", downloadUrl);
+            return;
+        }
+
+        var fileName = FilePathUtil.GetFilePath(_basePath, hash);
+        using var fileStream = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
+        var bufferSize = response.Content.Headers.ContentLength > 1024 * 1024 ? 4096 : 1024;
+        var buffer = new byte[bufferSize];
+
+        var bytesRead = 0;
+        while ((bytesRead = await (await response.Content.ReadAsStreamAsync().ConfigureAwait(false)).ReadAsync(buffer).ConfigureAwait(false)) > 0)
+        {
+            await fileStream.WriteAsync(buffer.AsMemory(0, bytesRead)).ConfigureAwait(false);
+        }
+
+        _metrics.IncGauge(MetricsAPI.GaugeFilesTotal);
+        _metrics.IncGauge(MetricsAPI.GaugeFilesTotalSize, FilePathUtil.GetFileInfoForHash(_basePath, hash).Length);
+    }
+
     public async Task<FileStream?> GetFileStream(string hash, string auth)
     {
         var fi = FilePathUtil.GetFileInfoForHash(_basePath, hash);
-        bool hasTransferTask = _currentTransfers.TryGetValue(hash, out var transferTask);
+        if (fi == null && IsMainServer) return null;
-        if (fi == null && !hasTransferTask)
+
+        if (fi == null && !_currentTransfers.ContainsKey(hash))
         {
-            if (IsMainServer) return null;
+            _currentTransfers[hash] = DownloadTask(hash, auth).ContinueWith(r => _currentTransfers.Remove(hash, out _));
-            if (transferTask == null)
-            {
-                _currentTransfers[hash] = Task.Run(async () =>
-                {
-                    // download file from remote
-                    var downloadUrl = new Uri(_remoteCacheSourceUri, hash);
-                    _logger.LogInformation("Did not find {hash}, downloading from {server}", hash, downloadUrl);
-                    using var client = new HttpClient();
-                    client.DefaultRequestHeaders.Add("Authorization", auth);
-                    var response = await client.GetAsync(downloadUrl, HttpCompletionOption.ResponseHeadersRead).ConfigureAwait(false);
-
-                    try
-                    {
-                        response.EnsureSuccessStatusCode();
-                    }
-                    catch (Exception ex)
-                    {
-                        _logger.LogWarning(ex, "Failed to download {url}", downloadUrl);
-                        return;
-                    }
-
-                    var fileName = FilePathUtil.GetFilePath(_basePath, hash);
-                    using var fileStream = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
-                    var bufferSize = response.Content.Headers.ContentLength > 1024 * 1024 ? 4096 : 1024;
-                    var buffer = new byte[bufferSize];
-
-                    var bytesRead = 0;
-                    while ((bytesRead = await (await response.Content.ReadAsStreamAsync().ConfigureAwait(false)).ReadAsync(buffer).ConfigureAwait(false)) > 0)
-                    {
-                        await fileStream.WriteAsync(buffer.AsMemory(0, bytesRead)).ConfigureAwait(false);
-                    }
-
-                    _metrics.IncGauge(MetricsAPI.GaugeFilesTotal);
-                    _metrics.IncGauge(MetricsAPI.GaugeFilesTotalSize, FilePathUtil.GetFileInfoForHash(_basePath, hash).Length);
-                });
-            }
-
-            transferTask = _currentTransfers[hash];
         }
 
-        if (transferTask != null)
+        if (fi == null && _currentTransfers.TryGetValue(hash, out var downloadTask))
         {
-            await transferTask.ConfigureAwait(false);
+            await downloadTask.ConfigureAwait(false);
-            _currentTransfers.Remove(hash, out _);
-            fi = FilePathUtil.GetFileInfoForHash(_basePath, hash);
-            if (fi == null) return null;
         }
 
+        fi = FilePathUtil.GetFileInfoForHash(_basePath, hash);
+        if (fi == null) return null;
+
         _fileStatisticsService.LogFile(hash, fi.Length);
 
-        int attempts = 0;
+        return new FileStream(fi.FullName, FileMode.Open, FileAccess.Read, FileShare.Inheritable | FileShare.Read);
-        while (attempts < 5)
-        {
-            try
-            {
-                return new FileStream(fi.FullName, FileMode.Open, FileAccess.Read, FileShare.Inheritable | FileShare.Read);
-            }
-            catch (Exception ex)
-            {
-                attempts++;
-                _logger.LogWarning(ex, "Error opening file, retrying");
-                await Task.Delay(TimeSpan.FromSeconds(1)).ConfigureAwait(false);
-            }
-        }
-
-        throw new IOException("Could not open file " + fi.FullName);
     }
 }