publik: add |clamp, |limit_low and |limit_high filters (#81223)

publik_django_templatetags/publik/templatetags/publik.py

@@ -99,13 +99,15 @@ def last(value):
         return ''
 
 
-def parse_decimal(value, default=Decimal(0)):
+def parse_decimal(value, default=Decimal(0), do_raise=False):
     if isinstance(value, str):
         # replace , by . for French users comfort
         value = value.replace(',', '.')
     try:
         return Decimal(value).quantize(Decimal('1.0000')).normalize()
     except (ArithmeticError, TypeError):
+        if do_raise:
+            raise
         return default
 
 
@@ -185,6 +187,32 @@ def sum_(list_):
         return ''
 
 
+@register.filter
+def clamp(value, minmax):
+    try:
+        value = parse_decimal(value, do_raise=True)
+        min_value, max_value = (parse_decimal(x, do_raise=True) for x in minmax.split())
+    except (ArithmeticError, TypeError, ValueError):
+        return ''
+    return max(min_value, min(value, max_value))
+
+
+@register.filter
+def limit_low(value, min_value):
+    try:
+        return max(parse_decimal(value, do_raise=True), parse_decimal(min_value, do_raise=True))
+    except (ArithmeticError, TypeError):
+        return ''
+
+
+@register.filter
+def limit_high(value, max_value):
+    try:
+        return min(parse_decimal(value, do_raise=True), parse_decimal(max_value, do_raise=True))
+    except (ArithmeticError, TypeError):
+        return ''
+
+
 @register.filter(is_safe=False)
 def duration(value, arg='short'):
     if arg not in ('short', 'long'):

tests/test_publik.py

@@ -336,6 +336,40 @@ def test_sum():
     assert t.render(Context()) == ''
 
 
+def test_clamp_templatetag():
+    tmpl = Template('{{ value|clamp:"3.5 5.5" }}')
+    assert tmpl.render(Context({'value': 4})) == '4'
+    assert tmpl.render(Context({'value': 6})) == '5.5'
+    assert tmpl.render(Context({'value': 3})) == '3.5'
+    assert tmpl.render(Context({'value': 'abc'})) == ''
+    assert tmpl.render(Context({'value': None})) == ''
+
+    tmpl = Template('{{ value|clamp:"3.5 5.5 7.5" }}')
+    assert tmpl.render(Context({'value': 4})) == ''
+
+    tmpl = Template('{{ value|clamp:"a b" }}')
+    assert tmpl.render(Context({'value': 4})) == ''
+
+
+def test_limit_templatetags():
+    for v in (3.5, '"3.5"', 'xxx'):
+        tmpl = Template('{{ value|limit_low:%s }}' % v)
+        assert tmpl.render(Context({'value': 4, 'xxx': 3.5})) == '4'
+        assert tmpl.render(Context({'value': 3, 'xxx': 3.5})) == '3.5'
+        assert tmpl.render(Context({'value': 'abc', 'xxx': 3.5})) == ''
+        assert tmpl.render(Context({'value': None, 'xxx': 3.5})) == ''
+        if v == 'xxx':
+            assert tmpl.render(Context({'value': 3, 'xxx': 'plop'})) == ''
+
+        tmpl = Template('{{ value|limit_high:%s }}' % v)
+        assert tmpl.render(Context({'value': 4, 'xxx': 3.5})) == '3.5'
+        assert tmpl.render(Context({'value': 3, 'xxx': 3.5})) == '3'
+        assert tmpl.render(Context({'value': 'abc', 'xxx': 3.5})) == ''
+        assert tmpl.render(Context({'value': None, 'xxx': 3.5})) == ''
+        if v == 'xxx':
+            assert tmpl.render(Context({'value': 3, 'xxx': 'plop'})) == ''
+
+
 def test_duration():
     context = Context({'value': 2})
     assert Template('{{ value|duration }}').render(context) == '2min'