Merge pull request #169 from ral-facilities/feature/where-filter-incl…

…uded-columns-#144

Allow WHERE Filter to use Included Fields for Python ICAT Backend

common/database/filters.py

@@ -10,12 +10,44 @@
 from common.models import db_models
 
 from sqlalchemy import asc, desc
+import logging
+
+log = logging.getLogger()
 
 
 class DatabaseWhereFilter(WhereFilter):
     def __init__(self, field, value, operation):
         super().__init__(field, value, operation)
 
+        self.included_field = None
+        self.included_included_field = None
+        self._extract_filter_fields(field)
+
+    def _extract_filter_fields(self, field):
+        """
+        Extract the related fields names and put them into separate variables
+
+        :param field: ICAT field names, separated by dots
+        :type field: :class:`str`
+        """
+
+        fields = field.split(".")
+        include_depth = len(fields)
+
+        log.debug("Fields: %s, Include Depth: %d", fields, include_depth)
+
+        if include_depth == 1:
+            self.field = fields[0]
+        elif include_depth == 2:
+            self.field = fields[0]
+            self.included_field = fields[1]
+        elif include_depth == 3:
+            self.field = fields[0]
+            self.included_field = fields[1]
+            self.included_included_field = fields[2]
+        else:
+            raise ValueError(f"Maximum include depth exceeded. {field}'s depth > 3")
+
     def apply_filter(self, query):
         try:
             field = getattr(query.table, self.field)

common/filters.py

@@ -21,11 +21,9 @@ class WhereFilter(QueryFilter):
     precedence = 1
 
     def __init__(self, field, value, operation):
+        # The field is set to None as a precaution but this should be set by the
+        # individual backend since backends deal with this data differently
         self.field = None
-        self.included_field = None
-        self.included_included_field = None
-        self._extract_filter_fields(field)
-
         self.value = value
         self.operation = operation
 
@@ -36,24 +34,6 @@ def __init__(self, field, value, operation):
                     " be in a list format e.g. [1, 2, 3]"
                 )
 
-    def _extract_filter_fields(self, field):
-        fields = field.split(".")
-        include_depth = len(fields)
-
-        log.debug("Fields: %s, Include Depth: %d", fields, include_depth)
-
-        if include_depth == 1:
-            self.field = fields[0]
-        elif include_depth == 2:
-            self.field = fields[0]
-            self.included_field = fields[1]
-        elif include_depth == 3:
-            self.field = fields[0]
-            self.included_field = fields[1]
-            self.included_included_field = fields[2]
-        else:
-            raise ValueError(f"Maximum include depth exceeded. {field}'s depth > 3")
-
 
 class DistinctFieldFilter(QueryFilter):
     precedence = 0

common/icat/filters.py

@@ -18,6 +18,7 @@
 class PythonICATWhereFilter(WhereFilter):
     def __init__(self, field, value, operation):
         super().__init__(field, value, operation)
+        self.field = field
 
     def apply_filter(self, query):
         log.info("Creating condition for ICAT where filter")