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Add image resizing example. Currently used base64 encoded data transfer and the 'jimp' module, neither of which are fast. Will replace these shortly.
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‎samples/misc/NodeServicesExamples/Controllers/HomeController.cs‎

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@@ -15,6 +15,11 @@ public IActionResult ES2015Transpilation()
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return View();
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}
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public IActionResult ImageResizing()
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{
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return View();
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}
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public IActionResult Error()
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{
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return View("~/Views/Shared/Error.cshtml");

‎samples/misc/NodeServicesExamples/Controllers/ResizeImage.cs‎

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

‎samples/misc/NodeServicesExamples/Node/resizeImage.js‎

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

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

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

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

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<ul>
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<li><a asp-action="ES2015Transpilation">ES2015 transpilation</a>
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<li><a asp-action="ImageResizing">Image resizing</a>
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</li>
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‎samples/misc/NodeServicesExamples/package.json‎

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"version": "0.0.0",
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"dependencies": {
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"babel-core": "^6.7.4",
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"babel-preset-es2015": "^6.6.0"
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"babel-preset-es2015": "^6.6.0",
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"jimp": "^0.2.24"
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}
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}

‎samples/misc/NodeServicesExamples/wwwroot/images/parrot.jpg‎

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