Algorithm context (#49)

* fix: reflect context changes in hashing algorithm
evrythng · Nov 2, 2022 · b038214 · b038214
1 parent 2584ac1
commit b038214
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Showing 9 changed files with 58 additions and 16 deletions.
diff --git a/README.md b/README.md
@@ -56,7 +56,7 @@ import * as epcis from 'epcis2.js';
 
 Or use a simple script tag to load it from the CDN:
 ```html
-<script src="https://cdn.jsdelivr.net/npm/epcis2.js@2.6.0/dist/epcis2.browser.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/epcis2.js@2.6.1/dist/epcis2.browser.js"></script>
 ```
 
 Then use in a browser `script` tag using the `epcis2` global variable:

diff --git a/example/node_example/example_with_full_possibility.js b/example/node_example/example_with_full_possibility.js
@@ -187,13 +187,17 @@ const buildObjectEvent = () => {
 }
 
 const buildAssociationEvent = () => {
+  const context = {
+    example: 'http://ns.example.com/epcis/',
+    ext1: 'http://example.com/ext1/',
+    ext2: 'http://example.com/ext2/',
+    ext3: 'http://example.com/ext3/'
+  };
+
   return new AssociationEvent(
     {
     "type": "AssociationEvent",
-    "@context": {
-      example: 'http://ns.example.com/epcis/',
-      ext1: 'http://example.com/ext1/'
-    },
+    "@context": context,
     "eventTime": "2019-11-01T13:00:00.000Z",
     "recordTime": "2005-04-05T02:33:31.116Z",
     "certificationInfo": "https://accreditation-council.example.org/certificate/ABC12345",
@@ -379,9 +383,9 @@ const buildAssociationEvent = () => {
     },
     "ext1:default": "stringAsDefaultValue",
     "ext1:int": "10",
-    "ext1:string": "string"
-  }
-);
+    "ext1:string": "string",
+    "cbvmda:site": 402
+  }).generateHashID(context);
 }
 
 const buildExtendedEvent = () => {
@@ -511,7 +515,7 @@ const sendACaptureRequestExample = async () => {
     console.log('\nEPCISDocument is valid ? ' + epcisDocument.isValid())
 
     // capture
-    console.log('Capture:')
+    console.log('Capture:');
     let res = await capture(epcisDocument);
     const cr = new CaptureResponse(res);
     await cr.pollForTheCaptureToFinish();

diff --git a/example/web-example/index.html b/example/web-example/index.html
@@ -3,7 +3,7 @@
 <head>
   <meta charset="UTF-8">
   <title>EPCIS2.js demo</title>
-  <script src="https://cdn.jsdelivr.net/npm/epcis2.js@2.6.0/dist/epcis2.browser.js" defer></script>
+  <script src="https://cdn.jsdelivr.net/npm/epcis2.js@2.6.1/dist/epcis2.browser.js" defer></script>
   <script>
     window.onload = () => {
       const doc = new epcis2.EPCISDocument();

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "epcis2.js",
-  "version": "2.6.0",
+  "version": "2.6.1",
   "description": "Javascript SDK for the EPCIS 2.0 standard",
   "main": "./dist/epcis2.node.js",
   "browser": "./dist/epcis2.browser.js",

diff --git a/src/hash_generator/EPCISEventToPreHashedString.js b/src/hash_generator/EPCISEventToPreHashedString.js
@@ -33,6 +33,17 @@ import cbv from '../cbv/cbv';
 // The rules of the algorithm are defined here :
 // https://github.com/RalphTro/epcis-event-hash-generator#algorithm
 
+const epcisDefaultContext = {
+  epcis: 'https://ref.gs1.org/epcis/',
+  cbv: 'https://ref.gs1.org/cbv/',
+  cbvmda: 'urn:epcglobal:cbv:mda:',
+  gs1: 'https://gs1.org/voc/',
+  rdfs: 'http://www.w3.org/2000/01/rdf-schema#',
+  owl: 'http://www.w3.org/2002/07/owl#',
+  xsd: 'http://www.w3.org/2001/XMLSchema#',
+  dcterms: 'http://purl.org/dc/terms/',
+};
+
 /**
  * Return the pre-hashed string corresponding to the field-value passed in parameter
  * @param {string} field
@@ -90,6 +101,9 @@ export const getPreHashStringFromCustomFieldElementList = (prefix, value, throwE
 export const getPreHashStringFromCustomFieldElement = (key, value, context, throwError) => {
   let field = key;
 
+  // comments are excluded from the pre-hash string.
+  if (key === 'rdfs:comment') return '';
+
   const splitKey = key.split(':');
 
   if (splitKey.length > 1) {
@@ -108,7 +122,7 @@ export const getPreHashStringFromCustomFieldElement = (key, value, context, thro
 
     field = key.replace(`${splitKey[0]}:`, `{${context[splitKey[0]]}}`);
   } else if (key.startsWith('#')) {
-    // if the key is '#text' for example, we don't want ot add the
+    // if the key is '#text' for example, we don't want to add the
     // key to the pre-hashed string
     return `=${value}`;
   }
@@ -547,7 +561,7 @@ export const eventToPreHashedString = (event, context, throwError = true) => {
   } else if (context instanceof Object) {
     contextObject = context;
   }
-  const extendedContext = { ...contextObject, ...getEventContexts(event) };
+  const extendedContext = { ...epcisDefaultContext, ...contextObject, ...getEventContexts(event) };
   const res = getOrderedPreHashString(
     event,
     extendedContext,

diff --git a/test/data/hashing/event-hash-reference-document3.json b/test/data/hashing/event-hash-reference-document3.json
@@ -38,7 +38,8 @@
         "example:userExt": {
           "@xmlns:example": "https://ns.example.com/epcis",
           "#text": "CD-34"
-        }
+        },
+        "cbvmda:sst": 201
       }
     ]
   }

diff --git a/test/data/hashing/samplePrehashesAndHashes.js b/test/data/hashing/samplePrehashesAndHashes.js
diff --git a/test/hashing/preHashing/preHashingUnitTests.spec.js b/test/hashing/preHashing/preHashingUnitTests.spec.js
@@ -722,6 +722,29 @@ describe('unit tests for pre-hashing', () => {
     )).to.throw();
   });
 
+  it('should return a valid pre-hash of custom fields', () => {
+    const str = eventToPreHashedString(
+      {
+        'cbvmda:key': 'test',
+      },
+      sampleContext,
+    );
+    expect(str).to.be.equal(
+      '{urn:epcglobal:cbv:mda:}key=test',
+    );
+
+    const str2 = eventToPreHashedString(
+      {
+        'dcterms:term': 'value',
+        action: 'OBSERVE',
+      },
+      sampleContext,
+    );
+    expect(str2).to.be.equal(
+      'action=OBSERVE{http://purl.org/dc/terms/}term=value',
+    );
+  });
+
   it('should automatically add the context from custom fields', () => {
     const str = eventToPreHashedString(
       {