resizing images ondemand

backend/Program.cs

@@ -2,20 +2,23 @@ using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Hosting;
+using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Drawing.Imaging;
 
 var builder = WebApplication.CreateBuilder(args);
 
 builder.Services.AddMemoryCache();
 
-builder.Services.AddCors(options =>
-{
-    options.AddPolicy("AllowAll",
-        policy =>
-        {
-            policy.AllowAnyOrigin()
-                  .AllowAnyHeader()
-                  .AllowAnyMethod();
-        });
+builder.Services.AddCors(options =>
+{
+    options.AddPolicy("AllowAll",
+        policy =>
+        {
+            policy.AllowAnyOrigin()
+                  .AllowAnyHeader()
+                  .AllowAnyMethod();
+        });
 });
 
 var app = builder.Build();
@@ -28,14 +31,14 @@ app.MapGet("/ping", () => "pong");
 app.MapGet("/api/v1/songs/{hash}", (string hash) =>
     {
 
-        return Results.Ok(new { hash });
+        return Results.Ok(new { hash });
     });
 
 app.MapGet("/api/v1/songs/recent", (int? limit, int? offset) =>
     {
         var limitValue = limit ?? 100; // default to 10 if not provided
         var offsetValue = offset ?? 0; // default to 0 if not provided
-
+
         return Results.Json(Osudb.Instance.GetRecent(limitValue, offsetValue));
     });
 
@@ -54,22 +57,22 @@ app.MapGet("/api/v1/songs/{hash}", (string hash) =>
 
 app.MapGet("/api/v1/collections/", async (int? limit, int? offset, [FromServices] IMemoryCache cache) =>
     {
-        const string cacheKey = "collections";
-
-        if (!cache.TryGetValue(cacheKey, out var collections))
-        {
-         
-            collections = Osudb.Instance.GetCollections();
-
-            var cacheEntryOptions = new MemoryCacheEntryOptions()
-                .SetSlidingExpiration(TimeSpan.FromDays(1)) 
-                .SetAbsoluteExpiration(TimeSpan.FromDays(3));  
-
-            cache.Set(cacheKey, collections, cacheEntryOptions);
+        const string cacheKey = "collections";
+
+        if (!cache.TryGetValue(cacheKey, out var collections))
+        {
+         
+            collections = Osudb.Instance.GetCollections();
+
+            var cacheEntryOptions = new MemoryCacheEntryOptions()
+                .SetSlidingExpiration(TimeSpan.FromDays(1)) 
+                .SetAbsoluteExpiration(TimeSpan.FromDays(3));
+
+            cache.Set(cacheKey, collections, cacheEntryOptions);
         }
 
-        return Results.Json(collections);
-
+        return Results.Json(collections);
+
     });
 
 app.MapGet("/api/v1/collection/{index}", (int index) =>
@@ -103,7 +106,7 @@ app.MapGet("/api/v1/audio/{*fileName}", async (string fileName, HttpContext cont
 });
 
 
-app.MapGet("/api/v1/images/{*filename}", async (string filename) =>
+app.MapGet("/api/v1/images/{*filename}", async (string filename, int? h, int? w) =>
 {
     var decodedFileName = Uri.UnescapeDataString(filename);
     var filePath = Path.Combine(Osudb.osufolder, "Songs", decodedFileName);
@@ -124,12 +127,72 @@ app.MapGet("/api/v1/images/{*filename}", async (string filename) =>
         ".webp" => "image/webp",
         _ => "application/octet-stream",
     };
-
-    var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, useAsync: true);
+    
+    if (w == null || h == null)
+    {
+        var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, useAsync: true);
+        return Results.Stream(fileStream, contentType, filename);
+    }
+    using var originalImage = new Bitmap(filePath);
+
+
+    // If resizing is requested, resize the image
+    Bitmap resizedImage;
+    if (w.HasValue || h.HasValue)
+    {
+        resizedImage = ResizeImage(originalImage, w, h);
+    }
+    else
+    {
+        resizedImage = new Bitmap(originalImage); // Keep original size
+    }
+
+    // Convert the resized image to a memory stream
+    var memoryStream = new MemoryStream();
+    resizedImage.Save(memoryStream, GetImageFormat(fileExtension));
+    memoryStream.Position = 0; // Reset stream position
+
+    return Results.File(memoryStream, contentType);
 
-    return Results.Stream(fileStream, contentType, filename);
 });
 
-
+static Bitmap ResizeImage(Image originalImage, int? width, int? height)
+{
+    int newWidth = width ?? originalImage.Width;
+    int newHeight = height ?? originalImage.Height;
+
+    if (width == null)
+    {
+        newWidth = originalImage.Width * newHeight / originalImage.Height;
+    }
+    else if (height == null)
+    {
+        newHeight = originalImage.Height * newWidth / originalImage.Width;
+    }
+
+    var resizedImage = new Bitmap(newWidth, newHeight);
+    using (var graphics = Graphics.FromImage(resizedImage))
+    {
+        graphics.CompositingQuality = CompositingQuality.HighQuality;
+        graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
+        graphics.SmoothingMode = SmoothingMode.HighQuality;
+        graphics.DrawImage(originalImage, 0, 0, newWidth, newHeight);
+    }
+
+    return resizedImage;
+}
+
+static ImageFormat GetImageFormat(string extension)
+{
+    return extension switch
+    {
+        ".jpg" or ".jpeg" => ImageFormat.Jpeg,
+        ".png" => ImageFormat.Png,
+        ".gif" => ImageFormat.Gif,
+        ".bmp" => ImageFormat.Bmp,
+        ".webp" => ImageFormat.Webp,
+        _ => ImageFormat.Png,
+    };
+}
 
 app.Run();