Improve safe mode for @graph use cases.

- Better handling for `@graph` top-level empty objects, objects with only ids, relative references, etc.
european-epc-competence-center · May 19, 2023 · ca09db4 · ca09db4
1 parent b5df97d
commit ca09db4
Show file tree

Hide file tree

Showing 3 changed files with 308 additions and 38 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -9,6 +9,9 @@
     updated.
 - Test on Node.js 20.x.
 
+### Fixed
+- Improve safe mode for `@graph` use cases.
+
 ## 8.1.1 - 2023-02-25
 
 ### Fixed

diff --git a/lib/expand.js b/lib/expand.js
@@ -372,48 +372,64 @@ api.expand = async ({
   // drop certain top-level objects that do not occur in lists
   if(_isObject(rval) &&
     !options.keepFreeFloatingNodes && !insideList &&
-    (activeProperty === null || expandedActiveProperty === '@graph')) {
+    (activeProperty === null ||
+      expandedActiveProperty === '@graph' ||
+      (_getContextValue(activeCtx, activeProperty, '@container') || [])
+        .includes('@graph')
+    )) {
     // drop empty object, top-level @value/@list, or object with only @id
-    if(count === 0 || '@value' in rval || '@list' in rval ||
-      (count === 1 && '@id' in rval)) {
-      // FIXME
-      if(options.eventHandler) {
-        // FIXME: one event or diff event for empty, @v/@l, {@id}?
-        let code;
-        let message;
-        if(count === 0) {
-          code = 'empty object';
-          message = 'Dropping empty object.';
-        } else if('@value' in rval) {
-          code = 'object with only @value';
-          message = 'Dropping object with only @value.';
-        } else if('@list' in rval) {
-          code = 'object with only @list';
-          message = 'Dropping object with only @list.';
-        } else if(count === 1 && '@id' in rval) {
-          code = 'object with only @id';
-          message = 'Dropping object with only @id.';
-        }
-        _handleEvent({
-          event: {
-            type: ['JsonLdEvent'],
-            code,
-            level: 'warning',
-            message,
-            details: {
-              value: rval
-            }
-          },
-          options
-        });
-      }
-      rval = null;
-    }
+    rval = _dropUnsafeObject({value: rval, count, options});
   }
 
   return rval;
 };
 
+/**
+ * Drop empty object, top-level @value/@list, or object with only @id
+ */
+function _dropUnsafeObject({
+  value,
+  count,
+  options
+}) {
+  if(count === 0 || '@value' in value || '@list' in value ||
+    (count === 1 && '@id' in value)) {
+    // FIXME
+    if(options.eventHandler) {
+      // FIXME: one event or diff event for empty, @v/@l, {@id}?
+      let code;
+      let message;
+      if(count === 0) {
+        code = 'empty object';
+        message = 'Dropping empty object.';
+      } else if('@value' in value) {
+        code = 'object with only @value';
+        message = 'Dropping object with only @value.';
+      } else if('@list' in value) {
+        code = 'object with only @list';
+        message = 'Dropping object with only @list.';
+      } else if(count === 1 && '@id' in value) {
+        code = 'object with only @id';
+        message = 'Dropping object with only @id.';
+      }
+      _handleEvent({
+        event: {
+          type: ['JsonLdEvent'],
+          code,
+          level: 'warning',
+          message,
+          details: {
+            value
+          }
+        },
+        options
+      });
+    }
+    return null;
+  }
+  return value;
+}
+
 /**
  * Expand each key and value of element adding to result
  *
@@ -933,8 +949,18 @@ async function _expandObject({
     if(container.includes('@graph') &&
       !container.some(key => key === '@id' || key === '@index')) {
       // ensure expanded values are arrays
-      expandedValue = _asArray(expandedValue)
-        .map(v => ({'@graph': _asArray(v)}));
+      // ensure an array
+      expandedValue = _asArray(expandedValue);
+      // check if needs to be dropped
+      const count = Object.keys(expandedValue[0]).length;
+      if(!options.isFrame && _dropUnsafeObject({
+        value: expandedValue[0], count, options
+      }) === null) {
+        // skip adding and continue
+        continue;
+      }
+      // convert to graph
+      expandedValue = expandedValue.map(v => ({'@graph': _asArray(v)}));
     }
 
     // FIXME: can this be merged with code above to simplify?

diff --git a/tests/misc.js b/tests/misc.js
@@ -1815,6 +1815,247 @@ _:b0 <ex:p> "[null]"^^<http://www.w3.org/1999/02/22-rdf-syntax-ns#JSON> .
       });
     });
 
+    it('should emit for @graph with empty object (1)', async () => {
+      const input =
+{
+  "@context": {
+    "p": {
+      "@id": "urn:p",
+      "@type": "@id",
+      "@container": "@graph"
+    }
+  },
+  "@id": "urn:id",
+  "p": {}
+}
+;
+      const expected = [];
+
+      await _test({
+        type: 'expand',
+        input,
+        expected,
+        eventCodeLog: [
+          'empty object',
+          'object with only @id'
+        ],
+        testNotSafe: true
+      });
+    });
+
+    it('should emit for ok @graph with empty object (2)', async () => {
+      const input =
+{
+  "@context": {
+    "p": {
+      "@id": "urn:p",
+      "@type": "@id",
+      "@container": "@graph"
+    },
+    "urn:t": {
+      "@type": "@id"
+    }
+  },
+  "@id": "urn:id",
+  "urn:t": "urn:id",
+  "p": {}
+}
+;
+      const expected =
+[
+  {
+    "@id": "urn:id",
+    "urn:t": [
+      {
+        "@id": "urn:id"
+      }
+    ]
+  }
+]
+;
+
+      await _test({
+        type: 'expand',
+        input,
+        expected,
+        eventCodeLog: [
+          'empty object'
+        ],
+        testNotSafe: true
+      });
+    });
+
+    it('should emit for @graph with relative @id (1)', async () => {
+      const input =
+{
+  "@context": {
+    "p": {
+      "@id": "urn:p",
+      "@type": "@id",
+      "@container": "@graph"
+    }
+  },
+  "@id": "urn:id",
+  "p": ["rel"]
+}
+;
+      const expected = [];
+
+      await _test({
+        type: 'expand',
+        input,
+        expected,
+        eventCodeLog: [
+          'object with only @id',
+          'object with only @id'
+        ],
+        testNotSafe: true
+      });
+    });
+
+    it('should emit for @graph with relative @id (2)', async () => {
+      const input =
+{
+  "@context": {
+    "p": {
+      "@id": "urn:p",
+      "@type": "@id",
+      "@container": "@graph"
+    },
+    "urn:t": {
+      "@type": "@id"
+    }
+  },
+  "@id": "urn:id",
+  "urn:t": "urn:id",
+  "p": ["rel"]
+}
+;
+      const expected =
+[
+  {
+    "@id": "urn:id",
+    "urn:t": [
+      {
+        "@id": "urn:id"
+      }
+    ]
+  }
+]
+;
+
+      await _test({
+        type: 'expand',
+        input,
+        expected,
+        eventCodeLog: [
+          'object with only @id',
+        ],
+        testNotSafe: true
+      });
+    });
+
+    it('should emit for @graph with relative @id (3)', async () => {
+      const input =
+{
+  "@context": {
+    "p": {
+      "@id": "urn:p",
+      "@type": "@id",
+      "@container": "@graph"
+    },
+    "urn:t": {
+      "@type": "@id"
+    }
+  },
+  "@id": "urn:id",
+  "urn:t": "urn:id",
+  "p": "rel"
+}
+;
+      const expected =
+[
+  {
+    "@id": "urn:id",
+    "urn:t": [
+      {
+        "@id": "urn:id"
+      }
+    ]
+  }
+]
+;
+
+      await _test({
+        type: 'expand',
+        input,
+        expected,
+        eventCodeLog: [
+          'object with only @id',
+        ],
+        testNotSafe: true
+      });
+    });
+
+    it('should emit for @graph with relative @id (4)', async () => {
+      const input =
+{
+  "@context": {
+    "p": {
+      "@id": "urn:p",
+      "@type": "@id",
+      "@container": "@graph"
+    },
+    "urn:t": {
+      "@type": "@id"
+    }
+  },
+  "@id": "urn:id",
+  "urn:t": "urn:id",
+  "p": {
+    "@id": "rel",
+    "urn:t": "urn:id2"
+  }
+}
+;
+      const expected =
+[
+  {
+    "@id": "urn:id",
+    "urn:t": [
+      {
+        "@id": "urn:id"
+      }
+    ],
+    "urn:p": [
+      {
+        "@graph": [
+          {
+            "@id": "rel",
+            "urn:t": [
+              {
+                "@id": "urn:id2"
+              }
+            ]
+          }
+        ]
+      }
+    ]
+  }
+]
+;
+
+      await _test({
+        type: 'expand',
+        input,
+        expected,
+        eventCodeLog: [
+          'relative @id reference',
+        ],
+        testNotSafe: true
+      });
+    });
+
     it('should emit for null @value', async () => {
       const input =
 {