Blog posts by Ninh Doan2019-04-22T08:47:02.0000000Zhttps://world.optimizely.com/blogs/ninh-doan/Optimizely WorldIntroducing: Episerver PDF Preview add-on<p>The <a href="/link/f7f020d815674508bd7fdc247e0d837b.aspx">Episerver PDF Preview</a> is the latest add-on that allows editors to preview PDF documents in edit view. </p>
<p>This add-on is based on <a href="https://mozilla.github.io/pdf.js/"><span class="caps">PDF</span>.js</a> version 2.0.943. </p>
<h2>Intergration with your current system</h2>
<p><span>In the </span><strong>PdfPreview</strong><span> package, there is a class named </span><span class="classLib">PdfFile</span><span> which handles uploaded files with the .pdf extension. </span></p>
<h3>1. The system does not have a model for handling PDF files</h3>
<p>If the system does not have a model for handling PDF files, the default<span> </span><span class="classLib">PdfFile</span><span> </span>model provided by the package is used. Editors can now preview PDF files in edit view without any extra steps.</p>
<h3>2. The system already has a model for handling PDF files</h3>
<p>By default, the<span> </span><strong><em><span class="classLib">ContentMediaResolver</span> </em></strong>class from Episerver CMS Core gets the first matching media implementation type registered for an extension. If there is an existing type registered for “pdf”, the<span> </span><span class="classLib">PdfFile</span><span> </span>media implementation in the Episerver package is used, but in this case the existing type should be chosen.</p>
<p>To change this default behavior, a media resolver class named<span> </span><strong><em><span class="classLib">PdfContentMediaResolver</span> </em></strong>is used to ignore the<span> </span><span class="classLib">PdfFile</span><span> </span>type in the Episerver package and thus, the existing registered media type is the candidate.</p>
<p><span class="classLib">PdfContentMediaResolver</span><span> </span>inherits<span> </span><span class="classLib">ContentMediaResolver</span><span> </span>and overrides the<span> </span><em><span class="classLib">Type GetFirstMatching(string extension) </span></em>method to handle the business logic above. </p>
<p>To turn on the PDF preview, the PDF media model must implement the<span> </span><em><span class="classLib">IPdfFile</span> </em>interface. For example:</p>
<pre class="language-csharp"><code>[ContentType(DisplayName = "PdfFile", GUID = "…", Description = "")]
[MediaDescriptor(ExtensionString = "pdf")]
public class PdfFile : MediaData, IPdfFile
{
}</code></pre>
<h3>Note: </h3>
<p><em><span class="classLib">PdfContentMediaResolver</span></em><em> </em>will ignore the<span> </span><span class="classLib">PdfFile</span><span> </span>type in the Episerver package when system has another type registered for “pdf”, no matter it is created before or after install package. If it is created after install package, AppPool restart is required to r<span>eflect the changes.</span></p>
<p><strong>Demo:</strong></p>
<ul>
<li>Before: </li>
</ul>
<p><img src="/link/c821c71eb59146129d041db7e3fe8521.aspx" /></p>
<ul>
<li>After:</li>
</ul>
<p><img src="/link/ae61d5e784024a359cacb7816a22fc5f.aspx" /></p>
<p> </p>2019-04-22T08:47:02.0000000ZBlog post