feat: implement a readonly and a disabled validator

CHANGES.rst

@@ -10,6 +10,8 @@ Unreleased
 -   Added shorter format to :class:`~fields.DateTimeLocalField`
     defaults :pr:`761`
 -   Stop support for python 3.7 :pr:`794`
+-   Implement :class:`~validators.ReadOnly` and
+    :class:`~validators.Disabled `:pr:`788`
 
 Version 3.0.1
 -------------

docs/validators.rst

@@ -73,6 +73,9 @@ Built-in validators
 
 .. autoclass:: wtforms.validators.NoneOf
 
+.. autoclass:: wtforms.validators.ReadOnly
+
+.. autoclass:: wtforms.validators.Disabled
 
 .. _custom-validators:
 

src/wtforms/validators.py

@@ -33,6 +33,10 @@
     "UUID",
     "ValidationError",
     "StopValidation",
+    "readonly",
+    "ReadOnly",
+    "disabled",
+    "Disabled",
 )
 
 
@@ -676,6 +680,40 @@ def __call__(self, hostname):
         return True
 
 
+class ReadOnly:
+    """
+    Set a field readonly.
+
+    Validation fails if the form data is different than the
+    field object data, or if unset, from the field default data.
+    """
+
+    def __init__(self):
+        self.field_flags = {"readonly": True}
+
+    def __call__(self, form, field):
+        if field.data != field.object_data:
+            raise ValidationError(field.gettext("This field cannot be edited"))
+
+
+class Disabled:
+    """
+    Set a field disabled.
+
+    Validation fails if the form data is different than the
+    field object data, or if unset, from the field default data.
+    """
+
+    def __init__(self):
+        self.field_flags = {"disabled": True}
+
+    def __call__(self, form, field):
+        if field.data != field.object_data:
+            raise ValidationError(
+                field.gettext("This field is disabled and cannot have a value")
+            )
+
+
 email = Email
 equal_to = EqualTo
 ip_address = IPAddress
@@ -689,3 +727,5 @@ def __call__(self, hostname):
 url = URL
 any_of = AnyOf
 none_of = NoneOf
+readonly = ReadOnly
+disabled = Disabled

src/wtforms/widgets/core.py

@@ -161,7 +161,7 @@ class Input:
     """
 
     html_params = staticmethod(html_params)
-    validation_attrs = ["required"]
+    validation_attrs = ["required", "disabled"]
 
     def __init__(self, input_type=None):
         if input_type is not None:
@@ -185,7 +185,14 @@ class TextInput(Input):
     """
 
     input_type = "text"
-    validation_attrs = ["required", "maxlength", "minlength", "pattern"]
+    validation_attrs = [
+        "required",
+        "disabled",
+        "readonly",
+        "maxlength",
+        "minlength",
+        "pattern",
+    ]
 
 
 class PasswordInput(Input):
@@ -198,7 +205,14 @@ class PasswordInput(Input):
     """
 
     input_type = "password"
-    validation_attrs = ["required", "maxlength", "minlength", "pattern"]
+    validation_attrs = [
+        "required",
+        "disabled",
+        "readonly",
+        "maxlength",
+        "minlength",
+        "pattern",
+    ]
 
     def __init__(self, hide_value=True):
         self.hide_value = hide_value
@@ -259,7 +273,7 @@ class FileInput(Input):
     """
 
     input_type = "file"
-    validation_attrs = ["required", "accept"]
+    validation_attrs = ["required", "disabled", "accept"]
 
     def __init__(self, multiple=False):
         super().__init__()
@@ -297,7 +311,7 @@ class TextArea:
     `rows` and `cols` ought to be passed as keyword args when rendering.
     """
 
-    validation_attrs = ["required", "maxlength", "minlength"]
+    validation_attrs = ["required", "disabled", "readonly", "maxlength", "minlength"]
 
     def __call__(self, field, **kwargs):
         kwargs.setdefault("id", field.id)
@@ -327,7 +341,7 @@ class Select:
     `choices` is a iterable of `(value, label, selected)` tuples.
     """
 
-    validation_attrs = ["required"]
+    validation_attrs = ["required", "disabled"]
 
     def __init__(self, multiple=False):
         self.multiple = multiple
@@ -385,7 +399,14 @@ class SearchInput(Input):
     """
 
     input_type = "search"
-    validation_attrs = ["required", "maxlength", "minlength", "pattern"]
+    validation_attrs = [
+        "required",
+        "disabled",
+        "readonly",
+        "maxlength",
+        "minlength",
+        "pattern",
+    ]
 
 
 class TelInput(Input):
@@ -394,7 +415,14 @@ class TelInput(Input):
     """
 
     input_type = "tel"
-    validation_attrs = ["required", "maxlength", "minlength", "pattern"]
+    validation_attrs = [
+        "required",
+        "disabled",
+        "readonly",
+        "maxlength",
+        "minlength",
+        "pattern",
+    ]
 
 
 class URLInput(Input):
@@ -403,7 +431,14 @@ class URLInput(Input):
     """
 
     input_type = "url"
-    validation_attrs = ["required", "maxlength", "minlength", "pattern"]
+    validation_attrs = [
+        "required",
+        "disabled",
+        "readonly",
+        "maxlength",
+        "minlength",
+        "pattern",
+    ]
 
 
 class EmailInput(Input):
@@ -412,7 +447,14 @@ class EmailInput(Input):
     """
 
     input_type = "email"
-    validation_attrs = ["required", "maxlength", "minlength", "pattern"]
+    validation_attrs = [
+        "required",
+        "disabled",
+        "readonly",
+        "maxlength",
+        "minlength",
+        "pattern",
+    ]
 
 
 class DateTimeInput(Input):
@@ -421,7 +463,7 @@ class DateTimeInput(Input):
     """
 
     input_type = "datetime"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
 
 class DateInput(Input):
@@ -430,7 +472,7 @@ class DateInput(Input):
     """
 
     input_type = "date"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
 
 class MonthInput(Input):
@@ -439,7 +481,7 @@ class MonthInput(Input):
     """
 
     input_type = "month"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
 
 class WeekInput(Input):
@@ -448,7 +490,7 @@ class WeekInput(Input):
     """
 
     input_type = "week"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
 
 class TimeInput(Input):
@@ -457,7 +499,7 @@ class TimeInput(Input):
     """
 
     input_type = "time"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
 
 class DateTimeLocalInput(Input):
@@ -466,7 +508,7 @@ class DateTimeLocalInput(Input):
     """
 
     input_type = "datetime-local"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
 
 class NumberInput(Input):
@@ -475,7 +517,7 @@ class NumberInput(Input):
     """
 
     input_type = "number"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "readonly", "max", "min", "step"]
 
     def __init__(self, step=None, min=None, max=None):
         self.step = step
@@ -498,7 +540,7 @@ class RangeInput(Input):
     """
 
     input_type = "range"
-    validation_attrs = ["required", "max", "min", "step"]
+    validation_attrs = ["required", "disabled", "max", "min", "step"]
 
     def __init__(self, step=None):
         self.step = step

tests/validators/test_disabled.py

@@ -0,0 +1,41 @@
+from tests.common import DummyPostData
+
+from wtforms import Form
+from wtforms import StringField
+from wtforms.validators import disabled
+
+
+def test_disabled():
+    class F(Form):
+        disabled = StringField(validators=[disabled()])
+
+    form = F(disabled="foobar")
+    assert "disabled" in form.disabled.flags
+    assert (
+        form.disabled()
+        == '<input disabled id="disabled" name="disabled" type="text" value="foobar">'
+    )
+    assert form.validate()
+
+    form = F(DummyPostData(disabled=["foobar"]), data={"disabled": "foobar"})
+    assert form.validate()
+
+    form = F(DummyPostData(disabled=["foobar"]), data={"disabled": "foobarbaz"})
+    assert not form.validate()
+
+    form = F(DummyPostData(disabled=["foobar"]))
+    assert not form.validate()
+
+
+def test_disabled_with_default():
+    class F(Form):
+        disabled = StringField(validators=[disabled()], default="foobar")
+
+    form = F(DummyPostData(disabled=["foobar"]))
+    assert form.validate()
+
+    form = F(DummyPostData(disabled=["foobar"]), data={"disabled": "foobarbaz"})
+    assert not form.validate()
+
+    form = F(DummyPostData(disabled=["foobarbaz"]), data={"disabled": "foobarbaz"})
+    assert form.validate()

tests/validators/test_readonly.py

@@ -0,0 +1,38 @@
+from tests.common import DummyPostData
+
+from wtforms import Form
+from wtforms import StringField
+from wtforms.validators import readonly
+
+
+def test_readonly():
+    class F(Form):
+        ro = StringField(validators=[readonly()])
+
+    form = F(ro="foobar")
+    assert "readonly" in form.ro.flags
+    assert form.ro() == '<input id="ro" name="ro" readonly type="text" value="foobar">'
+    assert form.validate()
+
+    form = F(DummyPostData(ro=["foobar"]), data={"ro": "foobar"})
+    assert form.validate()
+
+    form = F(DummyPostData(ro=["foobar"]), data={"ro": "foobarbaz"})
+    assert not form.validate()
+
+    form = F(DummyPostData(ro=["foobar"]))
+    assert not form.validate()
+
+
+def test_readonly_with_default():
+    class F(Form):
+        ro = StringField(validators=[readonly()], default="foobar")
+
+    form = F(DummyPostData(ro=["foobar"]))
+    assert form.validate()
+
+    form = F(DummyPostData(ro=["foobar"]), data={"ro": "foobarbaz"})
+    assert not form.validate()
+
+    form = F(DummyPostData(ro=["foobarbaz"]), data={"ro": "foobarbaz"})
+    assert form.validate()