#141: Allow multiple fields to be used in a distinct filter

- Inside a PythonICATDistinctFieldFilter, a where filter is created for each field in the request. These are then searched for in execute_icat_query() and the data is compiled to only include data from those fields

common/icat/filters.py

@@ -66,9 +66,11 @@ def create_condition(attribute_name, operator, value):
 
         conditions = {}
         # Removing quote marks when doing conditions with IN expressions
-        jpql_value = f"{value}" if isinstance(value, tuple) else f"'{value}'"
+        jpql_value = (
+            f"{value}" if isinstance(value, tuple) or operator == "!=" else f"'{value}'"
+        )
         conditions[attribute_name] = f"{operator} {jpql_value}"
-
+        log.debug("Conditions in ICAT where filter, %s", conditions)
         return conditions
 
 
@@ -79,11 +81,14 @@ def __init__(self, fields):
     def apply_filter(self, query):
         try:
             log.info("Adding ICAT distinct filter to ICAT query")
-            log.debug(f"Self fields: {self.fields}")
-
-            query.setAttribute(self.fields[0])
             query.setAggregate("DISTINCT")
 
+            # Using where filters to identify which fields to apply distinct too
+            for field in self.fields:
+                where_filter = PythonICATWhereFilter(field, "null", "ne")
+                where_filter.apply_filter(query)
+
+            log.debug("Fields for distinct filter: %s", self.fields)
         except ValueError as e:
             raise FilterError(e)
 

common/icat/helpers.py

@@ -162,21 +162,21 @@ def execute_icat_query(client, query, return_json_formattable=False):
         data = []
         log.debug(f"Conditions: {query.conditions}")
 
+        # For each condition, extract the attribute names and compile them into a list
         # TODO - The keys need to be checked to ensure they're != null
         attribute_names = query.conditions.keys()
         log.debug(f"Attribute Names: {attribute_names}")
 
-        # For each condition, extract the attribute names and compile them into a list
-        # TODO - Are attributes listed in alphabetical order? Which order should these
-        # attribute names be put into?
-
+        # Extract the data of the fields used in the distinct filter and return it as a
+        # response
         for result in query_result:
+            distinct_result = {}
             dict_result = result.as_dict()
-            
+
             for key, value in dict_result.items():
                 if key in attribute_names:
                     distinct_result[key] = value
-            
+
             data.append(distinct_result)
 
         return data