Add image resizing example. Currently used base64 encoded data transfer and the 'jimp' module, neither of which are fast. Will replace these shortly.

samples/misc/NodeServicesExamples/Controllers/HomeController.cs

@@ -15,6 +15,11 @@ namespace NodeServicesExamples.Controllers
             return View();
         }
 
+        public IActionResult ImageResizing()
+        {
+            return View();
+        }
+
         public IActionResult Error()
         {
             return View("~/Views/Shared/Error.cshtml");

samples/misc/NodeServicesExamples/Controllers/ResizeImage.cs

@@ -0,0 +1,61 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.NodeServices;
+using Microsoft.AspNetCore.StaticFiles;
+
+namespace NodeServicesExamples.Controllers
+{
+    public class ResizeImageController : Controller
+    {
+        private const int MaxDimension = 1000;
+
+        private IHostingEnvironment _environment;
+        private INodeServices _nodeServices;
+
+        public ResizeImageController(IHostingEnvironment environment, INodeServices nodeServices)
+        {
+            _environment = environment;
+            _nodeServices = nodeServices;
+        }
+
+        [Route("resize/{*imagePath}")]
+        public async Task<IActionResult> Index(string imagePath, int maxWidth, int maxHeight)
+        {
+            // Validate incoming params
+            if (maxWidth > MaxDimension || maxHeight > MaxDimension || (maxHeight <= 0 && maxWidth <= 0))
+            {
+                return BadRequest("Invalid dimensions");
+            }
+
+            // Locate source image on disk
+            var fileInfo = _environment.WebRootFileProvider.GetFileInfo(imagePath);
+            if (!fileInfo.Exists)
+            {
+                return NotFound();
+            }
+
+            // Invoke Node and convert the base64 result back to bytes
+            var mimeType = GetContentType(imagePath);
+            var resizedImage = await _nodeServices.Invoke<ResizeImageResult>("./Node/resizeImage", fileInfo.PhysicalPath, mimeType, maxWidth, maxHeight);
+            return File(Convert.FromBase64String(resizedImage.Base64), mimeType);
+        }
+
+        private string GetContentType(string path)
+        {
+            string result;
+            if (!new FileExtensionContentTypeProvider().TryGetContentType(path, out result))
+            {
+                result = "application/octet-stream";
+            }
+
+            return result;
+        }
+
+        private class ResizeImageResult
+        {
+            public string Base64 { get; set; }
+        }
+    }
+}

samples/misc/NodeServicesExamples/Node/resizeImage.js

@@ -0,0 +1,15 @@
+var Jimp = require('jimp');
+
+module.exports = function(cb, physicalPath, mimeType, maxWidth, maxHeight) {
+    Jimp.read(physicalPath, function (err, loadedImage) {
+        if (err) {
+            cb(err);
+        }
+
+        loadedImage
+            .contain(maxWidth > 0 ? maxWidth : Jimp.AUTO, maxHeight > 0 ? maxHeight : Jimp.AUTO)
+            .getBuffer(mimeType, function(err, buffer) {
+                cb(err, { base64: buffer && buffer.toString('base64') });
+            });
+    });
+}

samples/misc/NodeServicesExamples/Views/Home/ImageResizing.cshtml

@@ -0,0 +1,26 @@
+<h1>Image Resizing</h1>
+
+<p>
+    This sample shows how the NPM module <a href="https://www.npmjs.com/package/jimp"><code>jimp</code></a>
+    can be used for dynamic image resizing from within an ASP.NET Core application. There is one copy of the
+    following image on disk, but we can set up an MVC action method that returns it resized to fit within an
+    arbitrary width and height.
+</p>
+
+<p>
+    <em><a href="https://www.flickr.com/photos/dcoetzee/3572948635">Parrot</a>
+    by <a href="https://www.flickr.com/photos/dcoetzee/">D Coetzee</a>
+    is dedicated to the <a href="http://creativecommons.org/publicdomain/zero/1.0/">public domain (CC0)</a></em>
+</p>
+
+<h3>100px wide [<a href="/resize/images/parrot.jpg?maxWidth=100">open</a>]</h3>
+<img src="/resize/images/parrot.jpg?maxWidth=100" />
+
+<h3>200px wide [<a href="/resize/images/parrot.jpg?maxWidth=200">open</a>]</h3>
+<img src="/resize/images/parrot.jpg?maxWidth=200" />
+
+<h3>400px wide [<a href="/resize/images/parrot.jpg?maxWidth=400">open</a>]</h3>
+<img src="/resize/images/parrot.jpg?maxWidth=400" />
+
+<h3>800px wide [<a href="/resize/images/parrot.jpg?maxWidth=800">open</a>]</h3>
+<img src="/resize/images/parrot.jpg?maxWidth=800" />

samples/misc/NodeServicesExamples/Views/Home/Index.cshtml

@@ -8,5 +8,6 @@
 
 <ul>
     <li><a asp-action="ES2015Transpilation">ES2015 transpilation</a>
+    <li><a asp-action="ImageResizing">Image resizing</a>
 </li>
 

samples/misc/NodeServicesExamples/package.json

@@ -3,6 +3,7 @@
   "version": "0.0.0",
   "dependencies": {
     "babel-core": "^6.7.4",
-    "babel-preset-es2015": "^6.6.0"
+    "babel-preset-es2015": "^6.6.0",
+    "jimp": "^0.2.24"
   }
 }