Array reduction - part of multi-issue #1542

CHANGES_NEXT_RELEASE

@@ -1,6 +1,7 @@
-Fixed Issue:
-  * #1535  No matching with 'q' when matching subscriptions for deletion of an entity
+## Fixed Issues:
+  * #1535:  No matching with 'q' when matching subscriptions for deletion of an entity
+  * #1542:  Array Reduction (arrays of one single element are "flattened" to that very element) 
 
-New Features:
+## New Features:
   * Support for VocabularyProperty
   * Support for the new URL parameter "format" for output formats (normalized, concise, simplified)

scripts/requirements.txt

@@ -24,3 +24,4 @@
 Flask==2.0.3
 pyOpenSSL==22.0.0
 paho-mqtt==1.5.1
+Werkzeug==2.3.6

src/lib/logMsg/traceLevels.h

@@ -141,6 +141,7 @@ typedef enum TraceLevels
   LmtRegex,                            // Regular expressions - all of them
   LmtDateTime,                         // DateTime (ISO8601) conversion
   LmtMimeType,                         // MimeType
+  LmtArrayReduction,                   // Arrays of only one item are reduced to the item
 
   //
   // Legacy

src/lib/orionld/payloadCheck/pCheckAttribute.cpp

@@ -27,6 +27,7 @@
 
 extern "C"
 {
+#include "kbase/kMacros.h"                                       // K_FT
 #include "kalloc/kaStrdup.h"                                     // kaStrdup
 #include "kjson/KjNode.h"                                        // KjNode
 #include "kjson/kjLookup.h"                                      // kjLookup
@@ -105,6 +106,33 @@ static const char* attrTypeChangeTitle(OrionldAttributeType oldType, OrionldAttr
 
 
 
+// -----------------------------------------------------------------------------
+//
+// arrayReduce -
+//
+static void arrayReduce(KjNode* valueP)
+{
+  if (valueP->type != KjArray)
+    return;
+
+  if (valueP->value.firstChildP == NULL)
+    return;
+
+  if (valueP->value.firstChildP->next != NULL)
+    return;
+
+  // It's an array with one single item
+  KjNode* itemP = valueP->value.firstChildP;
+
+  valueP->type      = itemP->type;
+  valueP->value     = itemP->value;
+  valueP->lastChild = itemP->lastChild;
+
+  LM_T(LmtArrayReduction, ("Reduced an array of one single item to a JSON %s", kjValueType(valueP->type)));
+}
+
+
+
 // -----------------------------------------------------------------------------
 //
 // pCheckTypeFromContext -
@@ -166,24 +194,37 @@ static bool pCheckTypeFromContext(KjNode* attrP, OrionldContextItem* attrContext
       }
     }
     else if (strcmp(attrContextInfoP->type, "@set") == 0)
+    {
+      LM_T(LmtArrayReduction, ("the type for '%s' in the @context is '@set' - arrayReduction is set to FALSE", attrP->name));
       arrayReduction = false;
+    }
     else if (strcmp(attrContextInfoP->type, "@list") == 0)
+    {
+      LM_T(LmtArrayReduction, ("the type for '%s' in the @context is '@list' - arrayReduction is set to FALSE", attrP->name));
       arrayReduction = false;
+    }
   }
 
   //
   // Array Reduction
   //
+  LM_T(LmtArrayReduction, ("Attribute: '%s' - arrayReduction: %s, type '%s'", attrP->name, K_FT(arrayReduction), kjValueType(attrP->type)));
+
   if ((attrP->type == KjArray) && (arrayReduction == true))
   {
+    LM_T(LmtArrayReduction, ("The value of '%s' is an array and arrayReduction is ON", attrP->name));
     if ((attrP->value.firstChildP != NULL) && (attrP->value.firstChildP->next == NULL))
     {
+      LM_T(LmtArrayReduction, ("'%s' is an array of one single element => arrayReduction is PERFORMED", attrP->name));
+
       KjNode* arrayItemP = attrP->value.firstChildP;
 
       attrP->type      = arrayItemP->type;
       attrP->value     = arrayItemP->value;
       attrP->lastChild = arrayItemP->lastChild;  // Might be an array or object inside the array ...
     }
+    else
+      LM_T(LmtArrayReduction, ("'%s' is an array of zero od +1 elements => arrayReduction is NOT performed", attrP->name));
   }
 
   return true;
@@ -336,7 +377,7 @@ inline bool pCheckAttributeArray
   valueP->lastChild         = attrP->lastChild;
 
   pCheckAttributeTransform(attrP, "Property", valueP);
-
+  arrayReduce(valueP);
   return true;
 }
 
@@ -1022,14 +1063,23 @@ static bool pCheckAttributeObject
       if (isGeoJsonValue(valueP) == true)
         attributeType = GeoProperty;
       else
+      {
         attributeType = Property;
+        arrayReduce(valueP);
+      }
     }
     else if (objectP != NULL)
+    {
       attributeType = Relationship;
+      arrayReduce(objectP);
+    }
     else if (languageMapP != NULL)
       attributeType = LanguageProperty;
     else if (vocabP != NULL)
+    {
       attributeType = VocabularyProperty;
+      arrayReduce(vocabP);
+    }
     else
     {
       // If new attribute and no value field at all - error

test/functionalTest/cases/0000_ngsild/ngsild_PATCH_Entity-with-Relationship-array.test

@@ -95,17 +95,15 @@ Location: /ngsi-ld/v1/entities/urn:E1
 02. GET 'urn:E1'
 ================
 HTTP/1.1 200 OK
-Content-Length: 97
+Content-Length: 95
 Content-Type: application/json
 Date: REGEX(.*)
 Link: <https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-contextREGEX(.*)
 
 {
     "id": "urn:E1",
     "occupier": {
-        "object": [
-            "urn:ngsi-ld:Person:You"
-        ],
+        "object": "urn:ngsi-ld:Person:You",
         "type": "Relationship"
     },
     "type": "T"

test/functionalTest/cases/0000_ngsild/ngsild_issue_0310.test

@@ -123,7 +123,7 @@ Location: /ngsi-ld/v1/entities/urn:ngsi-ld:Entity02
 04. Get the Entity from step 3 and make sure the array is intact
 ================================================================
 HTTP/1.1 200 OK
-Content-Length: 97
+Content-Length: 95
 Content-Type: application/json
 Date: REGEX(.*)
 Link: <https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-contextREGEX(.*)
@@ -133,9 +133,7 @@ Link: <https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-contextREGEX(.*)
     "type": "T1",
     "urn:ngsi-ld:attrs:P1": {
         "type": "Property",
-        "value": [
-            12
-        ]
+        "value": 12
     }
 }