Added RenderPDF functionality

src/core/config/Categories.json

@@ -536,7 +536,9 @@
             "Hex Density chart",
             "Scatter chart",
             "Series chart",
-            "Heatmap chart"
+            "Heatmap chart",
+            "Render PDF"
+
         ]
     },
     {

src/core/operations/RenderPDF.mjs

@@ -0,0 +1,94 @@
+import { fromBase64, toBase64 } from "../lib/Base64.mjs";
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import Utils from "../Utils.mjs";
+
+/**
+ * Render PDF operation
+ */
+class RenderPDF extends Operation {
+
+    /**
+     * RenderPDF constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Render PDF";
+        this.module = "File";
+        this.description = "Displays the input as a PDF preview. Supports Raw and Base64 input formats.";
+        this.inputType = "string";
+        this.outputType = "byteArray";
+        this.presentType = "html";
+        this.args = [
+            {
+                "name": "Input format",
+                "type": "option",
+                "value": ["Base64","Raw"],
+            }
+        ];
+        this.checks = [
+            {
+                pattern: "^%PDF-",
+                flags: "",
+                args: ["Raw"],
+                useful: true,
+                output: {
+                    mime: "application/pdf"
+                }
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {byteArray}
+     */
+    run(input, args) {
+        const inputFormat = args[0];
+
+        if (!input.length) return [];
+
+        // Convert input to raw bytes
+        switch (inputFormat) {
+            case "Base64":
+                input = fromBase64(input, undefined, "byteArray");
+                break;
+            case "Raw":
+            default:
+                input = Utils.strToByteArray(input);
+                break;
+        }
+
+        // Check PDF signature
+        if (
+            input[0] !== 0x25 || // %
+            input[1] !== 0x50 || // P
+            input[2] !== 0x44 || // D
+            input[3] !== 0x46    // F
+        ) {
+            throw new OperationError("Input does not appear to be a PDF file.");
+        }
+
+        return input;
+    }
+
+    /**
+     * Displays the PDF using HTML for web apps.
+     *
+     * @param {byteArray} data
+     * @returns {html}
+     */
+    async present(data) {
+        if (!data.length) return "";
+
+        const base64 = toBase64(data);
+        const dataURI = "data:application/pdf;base64," + base64;
+
+        return `<iframe src="${dataURI}" style="width:100%;height:100%;border:1px solid #ccc;"></iframe>`;
+    }
+
+}
+
+export default RenderPDF;