Parameter by name (#5055)

* Add method get_parameter

- Return a parameter for a part, on name

* Add unit test for new method

* Adds template tag to retrieve parameter based on name

* Update docs

InvenTree/part/models.py

@@ -2176,6 +2176,16 @@ class Part(InvenTreeBarcodeMixin, InvenTreeNotesMixin, MetadataMixin, MPTTModel)
 
         return quantity
 
+    def get_parameter(self, name):
+        """Return the parameter with the given name.
+
+        If no matching parameter is found, return None.
+        """
+        try:
+            return self.parameters.get(template__name=name)
+        except PartParameter.DoesNotExist:
+            return None
+
     def get_parameters(self):
         """Return all parameters for this part, ordered by name."""
         return self.parameters.order_by('template__name')
@@ -3598,6 +3608,21 @@ class PartParameter(MetadataMixin, models.Model):
         blank=True,
     )
 
+    @property
+    def units(self):
+        """Return the units associated with the template"""
+        return self.template.units
+
+    @property
+    def name(self):
+        """Return the name of the template"""
+        return self.template.name
+
+    @property
+    def description(self):
+        """Return the description of the template"""
+        return self.template.description
+
     @classmethod
     def create(cls, part, template, data, save=False):
         """Custom save method for the PartParameter class"""

InvenTree/part/test_param.py

@@ -63,6 +63,20 @@ class TestParams(TestCase):
 
             self.assertEqual(len(p.metadata.keys()), 4)
 
+    def test_get_parameter(self):
+        """Test the Part.get_parameter method"""
+
+        prt = Part.objects.get(pk=3)
+
+        # Check that we can get a parameter by name
+        for name in ['Length', 'Width', 'Thickness']:
+            param = prt.get_parameter(name)
+            self.assertEqual(param.template.name, name)
+
+        # Check that an incorrect name returns None
+        param = prt.get_parameter('Not a parameter')
+        self.assertIsNone(param)
+
 
 class TestCategoryTemplates(TransactionTestCase):
     """Test class for PartCategoryParameterTemplate model"""

InvenTree/report/templatetags/report.py

@@ -181,7 +181,7 @@ def encode_svg_image(filename):
 
 
 @register.simple_tag()
-def part_image(part):
+def part_image(part: Part):
     """Return a fully-qualified path for a part image.
 
     Arguments:
@@ -200,6 +200,23 @@ def part_image(part):
     return uploaded_image(img)
 
 
+@register.simple_tag()
+def part_parameter(part: Part, parameter_name: str):
+    """Return a PartParameter object for the given part and parameter name
+
+    Arguments:
+        part: A Part object
+        parameter_name: The name of the parameter to retrieve
+
+    Returns:
+        A PartParameter object, or None if not found
+    """
+    if type(part) is Part:
+        return part.get_parameter(parameter_name)
+    else:
+        return None
+
+
 @register.simple_tag()
 def company_image(company):
     """Return a fully-qualified path for a company image.