add ZPL converter function

Author: william-davis-dev

src/core/config/Categories.json

@@ -537,7 +537,8 @@
             "HTML To Text",
             "Generate Lorem Ipsum",
             "Numberwang",
-            "XKCD Random Number"
+            "XKCD Random Number",
+            "ZPL Converter"
         ]
     },
     {

src/core/operations/ZPLConvert.mjs

@@ -0,0 +1,103 @@
+/**
+ * @author william-davis-dev
+ * @copyright Crown Copyright 2019
+ * @license Apache-2.0
+ */
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+
+/**
+ * Convert Label ZPL Into Usable Formats
+ */
+class ZPLConvert extends Operation {
+
+    /**
+     * ZPLConvert constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "ZPL Converter";
+        this.module = "Default";
+        this.description = [
+            "Takes ZPL (Zebra Printer Language)-encoded text data and converts renders it to readable images.",
+            "<br><br>",
+            "Uses the  <a href='https://labelary.com/service.html'>Labelary</a> API for full support of all ZPL instructions.",
+            "<br><br>",
+            "Use the 'Render Image' operation to see the final label output."
+        ].join("\n");
+        this.infoURL = "https://en.wikipedia.org/wiki/Zebra_Programming_Language";
+        this.inputType = "string";
+        this.outputType = "ArrayBuffer";
+        this.manualBake = true;
+        this.args = [
+            {
+                name: "Width",
+                type: "number",
+                value: 4
+            },
+            {
+                name: "Height",
+                type: "number",
+                value: 6
+            },
+            {
+                name: "Label Index",
+                type: "number",
+                value: 0
+            },
+            {
+                name: "Label Resolution",
+                type: "option",
+                value: [
+                    "6 dpmm (152 dpi)",
+                    "8 dpmm (203 dpi)",
+                    "12 dpmm (300 dpi)",
+                    "24 dpmm (600 dpi)"
+                ],
+                defaultIndex: 1
+            },
+            {
+                name: "Labelary Endpoint",
+                type: "text",
+                value: "https://api.labelary.com"
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {ArrayBuffer}
+     */
+    run(input, args) {
+        const [widthArg, heightArg, index, labelResolutionArg, labelaryApi] = args;
+        // The first segment of the resolution arg is the numeric indicator of the resolution
+        const labelResolution = labelResolutionArg.toString().split(" ")[0];
+
+        const labelaryUrl = `${labelaryApi}/v1/printers/${labelResolution}dpmm/labels/${widthArg}x${heightArg}/${index}`
+
+        return fetch(labelaryUrl, {
+            method: 'POST',
+            headers: {"accept": "image/png", "Content-Type": "application/x-www-form-urlencoded"},
+            body: input,
+        }).then(response => {
+            if (!response.ok) {
+                return response.text()
+                    .then(text => {
+                        throw new OperationError(text);
+                    });
+            }
+            return response.blob();
+        }).then(blob => {
+            return blob.arrayBuffer()
+        }).then(data => {
+            return data;
+        }).catch(e => {
+            throw new OperationError(`Error making request to ${labelaryUrl} with message: ${e.toString()}`);
+        });
+
+    }
+}
+
+export default ZPLConvert;