Use seekable streams for plate1 storage (#146)

src/WWT.Azure/AzureWwtExtensions.cs

@@ -29,7 +29,7 @@ namespace WWT.Azure
                     services.AddTransient(_ => new BlobServiceClient(azureOptions.StorageAccount));
                 }
 
-                services.AddSingleton<IPlateTilePyramid, AzurePlateTilePyramid>();
+                services.AddSingleton<IPlateTilePyramid, SeekableAzurePlateTilePyramid>();
             }
             else
             {

src/WWT.Azure/SeekableAzurePlateTilePyramid.cs

@@ -0,0 +1,56 @@
+using Azure.Storage.Blobs;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using WWTWebservices;
+
+namespace WWT.Azure
+{
+    public class SeekableAzurePlateTilePyramid : IPlateTilePyramid
+    {
+        private readonly Func<string, BlobClient> _blobRetriever;
+        private readonly BlobContainerClient _container;
+
+        public SeekableAzurePlateTilePyramid(AzurePlateTilePyramidOptions options, BlobServiceClient service)
+        {
+            _container = service.GetBlobContainerClient(options.Container);
+
+            var cache = new ConcurrentDictionary<string, BlobClient>();
+            _blobRetriever = plateName => cache.GetOrAdd(plateName, _container.GetBlobClient);
+        }
+
+        Stream IPlateTilePyramid.GetStream(string pathPrefix, string plateName, int level, int x, int y)
+            => GetStream(plateName, level, x, y);
+
+        public Stream GetStream(string plateName, int level, int x, int y)
+        {
+            var client = _blobRetriever(plateName);
+            var download = client.OpenRead();
+
+            return PlateTilePyramid.GetImageStream(download, level, x, y);
+        }
+
+        public async IAsyncEnumerable<string> GetPlateNames([EnumeratorCancellation] CancellationToken token)
+        {
+            await foreach (var item in _container.GetBlobsByHierarchyAsync(delimiter: "/", cancellationToken: token))
+            {
+                var prefix = item.Prefix.TrimEnd('/');
+                yield return $"{prefix}.plate";
+            }
+        }
+
+        Stream IPlateTilePyramid.GetStream(string pathPrefix, string plateName, int tag, int level, int x, int y)
+            => GetStream(plateName, tag, level, x, y);
+
+        public Stream GetStream(string plateName, int tag, int level, int x, int y)
+        {
+            var client = _blobRetriever(plateName);
+            var stream = client.OpenRead();
+
+            return PlateFile2.GetImageStream(stream, tag, level, x, y);
+        }
+    }
+}

src/WWT.PlateFiles/PlateTilePyramid.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using WWT.PlateFiles;
 
 /* Jonathan Fay wrote this, except for the bits polluted by Dinoj, which are between <dinoj>...</dinoj> tags
 *  The header information in the .plate files is being upgraded.
@@ -103,7 +104,7 @@ namespace WWTWebservices
                 fs.Close();
             }
         }
-        
+
 
         public void AddStream(Stream inputStream, int level, int x, int y)
         {
@@ -123,8 +124,7 @@ namespace WWTWebservices
             int lenRead = inputStream.Read(buf, 0, len);
             fileStream.Write(buf, 0, len);
             inputStream.Close();
-        }   
-        
+        }
 
         public void UpdateHeaderAndClose()
         {
@@ -235,6 +235,17 @@ namespace WWTWebservices
             }
             return null;
         }
+
+        public static Stream GetImageStream(Stream f, int level, int x, int y)
+        {
+            var offset = GetFileIndexOffset(level, x, y);
+            f.Seek(offset, SeekOrigin.Begin);
+
+            var start = GetNodeInfo(f, offset, out var length);
+
+            return new StreamSlice(f, start, length);
+        }
+
         static public Stream GetFileStream(string filename, int level, int x, int y)
         {
             uint offset = GetFileIndexOffset(level, x, y);
@@ -254,28 +265,8 @@ namespace WWTWebservices
             }
             return ms;
         }
-/*
 
-        public byte[] GetTile(int level, int x, int y)
-        {
-            uint offset = GetFileIndexOffset(level, x, y);
-            uint length;
-            uint start;
-
-            MemoryStream ms = null;
-            if (_readStream == null)
-                _readStream = File.Open(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
-            _readStream.Seek(offset, SeekOrigin.Begin);
-            start = GetNodeInfo(_readStream, offset, out length);
-            if (length == 0)
-                return null;
-            byte[] buffer = new byte[length];
-            _readStream.Seek(start, SeekOrigin.Begin);
-            _readStream.Read(buffer, 0, (int)length);
-            return buffer;
-        }
-*/
-        static public uint GetNodeInfo(FileStream fs, uint offset, out uint length)
+        public static uint GetNodeInfo(Stream fs, uint offset, out uint length)
         {
             Byte[] buf = new Byte[8];
             fs.Seek(offset, SeekOrigin.Begin);
@@ -332,7 +323,6 @@ namespace WWTWebservices
         {
             this.level = level;
             fileMap = new NodeInfo[(int)Math.Pow(2, level), (int)Math.Pow(2, level)];
-
         }
     }
 

src/WWT.Providers/Providers/DSSProvider.cs

@@ -31,7 +31,7 @@ namespace WWT.Providers
             {
                 context.Response.ContentType = "image/png";
 
-                using (var s = _plateTile.GetStream(_options.WwtTilesDir, "dssterrapixel.plate", level, tileX, tileY))
+                using (var s = _plateTile.GetStream(_options.WwtTilesDir, "DSSTerraPixel.plate", level, tileX, tileY))
                 {
                     s.CopyTo(context.Response.OutputStream);
                     context.Response.Flush();

src/WWT.Providers/Providers/DSSToastProvider.cs

@@ -33,7 +33,7 @@ namespace WWT.Providers
             {
                 context.Response.ContentType = "image/png";
 
-                using (var s = _plateTile.GetStream(_options.WwtTilesDir, "dsstoast.plate", level, tileX, tileY))
+                using (var s = _plateTile.GetStream(_options.WwtTilesDir, "DSSToast.plate", level, tileX, tileY))
                 {
                     s.CopyTo(context.Response.OutputStream);
                     context.Response.Flush();

tests/WWT.Providers.Tests/DSSTests.cs

@@ -21,7 +21,7 @@ namespace WWT.Providers.Tests
             }
             else if (level < 8)
             {
-                return plateTiles.GetStream(Options.WwtTilesDir, "dssterrapixel.plate", level, x, y);
+                return plateTiles.GetStream(Options.WwtTilesDir, "DSSTerraPixel.plate", level, x, y);
             }
             else
             {

tests/WWT.Providers.Tests/DSSToastTests.cs

@@ -21,7 +21,7 @@ namespace WWT.Providers.Tests
             }
             else if (level < 8)
             {
-                return plateTiles.GetStream(Options.WwtTilesDir, "dsstoast.plate", level, x, y);
+                return plateTiles.GetStream(Options.WwtTilesDir, "DSSToast.plate", level, x, y);
             }
             else
             {