Add Template operation for basic JSON rendering

package-lock.json

@@ -46,6 +46,7 @@
         "file-saver": "^2.0.5",
         "flat": "^6.0.1",
         "geodesy": "1.1.3",
+        "handlebars": "^4.7.8",
         "highlight.js": "^11.9.0",
         "ieee754": "^1.2.1",
         "jimp": "^0.22.12",
@@ -10842,6 +10843,27 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/handlebars": {
+      "version": "4.7.8",
+      "resolved": "https://registry.npmjs.org/handlebars/-/handlebars-4.7.8.tgz",
+      "integrity": "sha512-vafaFqs8MZkRrSX7sFVUdo3ap/eNiLnb4IakshzvP56X5Nr1iGKAIqdX6tMlm6HcNRIkr6AxO5jFEoJzzpT8aQ==",
+      "license": "MIT",
+      "dependencies": {
+        "minimist": "^1.2.5",
+        "neo-async": "^2.6.2",
+        "source-map": "^0.6.1",
+        "wordwrap": "^1.0.0"
+      },
+      "bin": {
+        "handlebars": "bin/handlebars"
+      },
+      "engines": {
+        "node": ">=0.4.7"
+      },
+      "optionalDependencies": {
+        "uglify-js": "^3.1.4"
+      }
+    },
     "node_modules/has-ansi": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/has-ansi/-/has-ansi-2.0.0.tgz",
@@ -13654,7 +13676,6 @@
       "version": "2.6.2",
       "resolved": "https://registry.npmjs.org/neo-async/-/neo-async-2.6.2.tgz",
       "integrity": "sha512-Yd3UES5mWCSqR+qNT93S3UoYUkqAZ9lLg8a7g9rimsWmYGK8cVToA4/sF3RrshdyV3sAGMXVUmpMYOw+dLpOuw==",
-      "dev": true,
       "license": "MIT"
     },
     "node_modules/netmask": {
@@ -16859,7 +16880,6 @@
       "version": "0.6.1",
       "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
       "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==",
-      "devOptional": true,
       "license": "BSD-3-Clause",
       "engines": {
         "node": ">=0.10.0"
@@ -18877,6 +18897,12 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/wordwrap": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/wordwrap/-/wordwrap-1.0.0.tgz",
+      "integrity": "sha512-gvVzJFlPycKc5dZN4yPkP8w7Dc37BtP1yczEneOb4uq34pXZcvrtRTmWV8W+Ume+XCxKgbjM+nevkyFPMybd4Q==",
+      "license": "MIT"
+    },
     "node_modules/worker-loader": {
       "version": "3.0.8",
       "resolved": "https://registry.npmjs.org/worker-loader/-/worker-loader-3.0.8.tgz",

package.json

@@ -132,6 +132,7 @@
     "file-saver": "^2.0.5",
     "flat": "^6.0.1",
     "geodesy": "1.1.3",
+    "handlebars": "^4.7.8",
     "highlight.js": "^11.9.0",
     "ieee754": "^1.2.1",
     "jimp": "^0.22.12",

src/core/config/Categories.json

@@ -373,7 +373,8 @@
             "Extract EXIF",
             "Extract ID3",
             "Extract Files",
-            "RAKE"
+            "RAKE",
+            "Template"
         ]
     },
     {

src/core/operations/Template.mjs

@@ -0,0 +1,53 @@
+/**
+ * @author kendallgoto [k@kgo.to]
+ * @copyright Crown Copyright 2025
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import Handlebars from "handlebars";
+
+/**
+ * Template operation
+ */
+class Template extends Operation {
+
+    /**
+     * Template constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Template";
+        this.module = "Handlebars";
+        this.description = "Render a template with Handlebars/Mustache substituting variables using JSON input. Templates will be rendered to plain-text only, to prevent XSS.";
+        this.infoURL = "https://handlebarsjs.com/";
+        this.inputType = "JSON";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "Template definition (.handlebars)",
+                type: "text",
+                value: ""
+            }
+        ];
+    }
+
+    /**
+     * @param {JSON} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const [templateStr] = args;
+        try {
+            const template = Handlebars.compile(templateStr);
+            return template(input);
+        } catch (e) {
+            throw new OperationError(e);
+        }
+    }
+}
+
+export default Template;

tests/operations/index.mjs

@@ -157,6 +157,7 @@ import "./tests/Subsection.mjs";
 import "./tests/SwapCase.mjs";
 import "./tests/SymmetricDifference.mjs";
 import "./tests/TakeNthBytes.mjs";
+import "./tests/Template.mjs";
 import "./tests/TextEncodingBruteForce.mjs";
 import "./tests/ToFromInsensitiveRegex.mjs";
 import "./tests/TranslateDateTimeFormat.mjs";

tests/operations/tests/Template.mjs

@@ -0,0 +1,53 @@
+/**
+ * @author kendallgoto [k@kgo.to]
+ * @copyright Crown Copyright 2025
+ * @license Apache-2.0
+ */
+
+import TestRegister from "../../lib/TestRegister.mjs";
+TestRegister.addTests([
+    {
+        "name": "Template: Simple Print",
+        "input": "{}",
+        "expectedOutput": "Hello, world!",
+        "recipeConfig": [
+            {
+                "op": "Template",
+                "args": ["Hello, world!"]
+            }
+        ]
+    },
+    {
+        "name": "Template: Print Basic Variables",
+        "input": "{\"one\": 1, \"two\": 2}",
+        "expectedOutput": "1 2",
+        "recipeConfig": [
+            {
+                "op": "Template",
+                "args": ["{{ one }} {{ two }}"]
+            }
+        ]
+    },
+    {
+        "name": "Template: Partials",
+        "input": "{\"users\":[{\"name\":\"Someone\",\"age\":25},{\"name\":\"Someone Else\",\"age\":32}]}",
+        "expectedOutput": "Name: Someone\nAge: 25\n\nName: Someone Else\nAge: 32\n\n",
+        "recipeConfig": [
+            {
+                "op": "Template",
+                "args": ["{{#*inline \"user\"}}\nName: {{ name }}\nAge: {{ age }}\n{{/inline}}\n{{#each users}}\n{{> user}}\n\n{{/each}}"]
+            }
+        ]
+    },
+    {
+        "name": "Template: Disallow XSS",
+        "input": "{\"test\": \"<script></script>\"}",
+        "expectedOutput": "<script></script>&lt;script&gt;&lt;/script&gt;",
+        "recipeConfig": [
+            {
+                "op": "Template",
+                "args": ["<script></script>{{ test }}"]
+            }
+        ]
+    }
+]);