node.js: Basic example web service transforming GS1 syntaxes

src/js-wasm/example-web-service.node.mjs

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+/*
+ *  Basic node.js example web service that uses the JavaScript wrapper around
+ *  the WASM build of the GS1 Barcode Syntax Engine.
+ *
+ *  Requirements:
+ *
+ *    - Run with Node.js >= v18 for stable ES6 module support
+ *
+ *  Copyright (c) 2022-2025 GS1 AISBL.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *
+ *  Example calls:
+ *
+ *    $ curl -i 'http://127.0.0.1:3030/aiDataStr?input=(02)12312312312319(99)ASDFEE&includeDataTitlesInHRI'
+ *
+ *    HTTP/1.1 400 Bad Request
+ *    Content-Type: text/plain
+ *    ...
+ *    Required AIs for AI (02) are not satisfied: 37
+ *
+ *
+ *    $ curl -i 'http://127.0.0.1:3030/aiDataStr?input=(02)12312312312319(99)ASDFEE&includeDataTitlesInHRI&noValidateRequisiteAIs'
+ *    HTTP/1.1 200 OK
+ *    Content-Type: text/plain
+ *    ...
+ *    Barcode message:      ^021231231231231999ASDFEE
+ *    AI element string:    (02)12312312312319(99)ASDFEE
+ *    GS1 Digital Link URI: ⧚ Cannot create a DL URI without a primary key AI ⧚
+ *    HRI:
+ *           CONTENT (02) 12312312312319
+ *           INTERNAL (99) ASDFEE
+ *
+ *    $ curl -i 'http://127.0.0.1:3030/dataStr?input=HTTPS://ID.EXAMPLE.ORG/01/12312312312319?99=ASDFEE&output=json'
+ *    HTTP/1.1 200 OK
+ *    Content-Type: application/json
+ *    ...
+ *    {"dataStr":"http://ID.EXAMPLE.ORG/01/12312312312319?99=ASDFEE","aiDataStr":"(01)12312312312319(99)ASDFEE","dlURI":"https://id.gs1.org/01/12312312312319?99=ASDFEE","hri":["(01) 12312312312319","(99) ASDFEE"]}
+ *
+ */
+
+"use strict";
+
+import { GS1encoder } from "./gs1encoder.mjs";
+
+var gs1encoder = new GS1encoder();
+await gs1encoder.init();
+
+import * as http from 'http';
+import * as url from 'url';
+
+
+/*
+ *  User-defined tunables
+ *
+ */
+const bind = '127.0.0.1';  // "0.0.0.0" to allow remote connections
+const port = 3030;
+
+
+http.createServer(function(req, res) {
+
+    var parse = url.parse(req.url, true);
+    var pathname = parse.pathname;
+    var params = parse.query;
+
+    if (req.method !== 'GET') {
+        res.writeHead(405, {'Content-Type': 'text/plain'});
+        res.write("Method Not Allowed\n");
+        res.end();
+        return;
+    }
+
+    var inpStr = params.input;
+    if (!inpStr) {
+        res.writeHead(400, {'Content-Type': 'text/plain'});
+        res.write("Bad Request: 'input' query parameter must be defined\n");
+        res.end();
+        return;
+    }
+
+    try {
+
+        /*
+         *  Example of setting options
+         *
+         */
+        gs1encoder.includeDataTitlesInHRI = "includeDataTitlesInHRI" in params;
+        gs1encoder.permitUnknownAIs = "permitUnknownAIs" in params;
+        gs1encoder.permitZeroSuppressedGTINinDLuris = "permitZeroSuppressedGTINinDLuris" in params;
+        gs1encoder.setValidationEnabled(GS1encoder.validation.RequisiteAIs, !("noValidateRequisiteAIs" in params));
+
+        /*
+         *  Set the data
+         *
+         */
+        switch (pathname) {
+            case '/dataStr':
+                gs1encoder.dataStr = inpStr;
+                break;
+            case '/aiDataStr':
+                gs1encoder.aiDataStr = inpStr;
+                break;
+            default:
+                res.writeHead(404, {'Context-Type': 'text/plain'});
+                res.end('Not Found');
+                return;
+        }
+
+    } catch (err) {
+        res.writeHead(400, {'Content-Type': 'text/plain'});
+        res.write(err.message + "\n");
+        var markup = gs1encoder.errMarkup;
+        if (markup)
+            res.write(markup.replace(/\|/g, "⧚") + "\n");
+        res.end();
+        return;
+    }
+
+    var dataStr = gs1encoder.dataStr;
+    var aiDataStr = gs1encoder.aiDataStr;
+    var dlURI; var dlURIerr;
+    try { dlURI = gs1encoder.getDLuri(null); } catch (err) { dlURI = null; dlURIerr = err; }
+    var hri = gs1encoder.hri;
+
+    if (params.output === 'json') {
+
+        res.writeHead(200, {'Content-Type': 'application/json'});
+        var ret = {
+            dataStr: dataStr,
+            aiDataStr: aiDataStr,
+            dlURI: dlURI,
+            hri: hri
+        }
+        res.write(JSON.stringify(ret) + "\n");
+        res.end();
+
+    } else {  // Plaintext response
+
+        res.writeHead(200, {'Content-Type': 'text/plain'});
+        res.write("Barcode message:      " + gs1encoder.dataStr + "\n");
+        res.write("AI element string:    " + (aiDataStr ?? "⧚ Not AI-based data ⧚") + "\n");
+        res.write("GS1 Digital Link URI: " + (dlURI ?? "⧚ " + dlURIerr.message + " ⧚") + "\n");
+        res.write("HRI:                  " + (dataStr !== "" && hri.length == 0 ? "⧚ Not AI-based data ⧚": "") + "\n");
+        hri.forEach(ai => res.write("       " + ai + "\n"));
+        res.end();
+
+    }
+
+}).listen(port, bind);
+
+console.log("Web service is running on %s:%d", bind, port);
+