utils: add form field for template and condition's templates (#74797)

passerelle/utils/forms.py

@@ -15,8 +15,34 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from django import forms
-from django.core import validators
+from django.core import exceptions, validators
+from django.template import Template, TemplateSyntaxError
+from django.utils.translation import gettext_lazy as _
 
 
 class LDAPURLField(forms.URLField):
     default_validators = [validators.URLValidator(schemes=['ldap', 'ldaps'])]
+
+
+def validate_condition_template(condition_template):
+    real_template = f'{{% if {condition_template} %}}OK{{% endif %}}'
+    try:
+        Template(real_template)
+    except (TemplateSyntaxError, OverflowError) as e:
+        raise exceptions.ValidationError(_('syntax error: %s') % e, code='syntax-error')
+
+
+class ConditionField(forms.CharField):
+    default_validators = [validate_condition_template]
+
+
+def validate_template(template):
+    try:
+        Template(template)
+    except (TemplateSyntaxError, OverflowError) as e:
+        raise exceptions.ValidationError(_('syntax error: %s') % e, code='syntax-error')
+
+
+class TemplateField(forms.CharField):
+    default_validators = [validate_template]
+    widget = forms.Textarea

passerelle/utils/templates.py

@@ -20,7 +20,7 @@ Disable autoescaping.
 '''
 
 from django.core.exceptions import ValidationError
-from django.template import TemplateSyntaxError
+from django.template import Context, Template, TemplateSyntaxError
 from django.template.backends.django import DjangoTemplates
 from django.utils.translation import gettext as _
 
@@ -46,3 +46,15 @@ def validate_template(template_string):
         make_template(template_string)
     except TemplateSyntaxError as e:
         raise ValidationError(_('Invalid template: %s') % e)
+
+
+def evaluate_condition(condition_template, context_dict):
+    template = Template(f'{{% if {condition_template} %}}OK{{% endif %}}')
+    context = Context(context_dict)
+    return template.render(context) == 'OK'
+
+
+def evaluate_template(template, context_dict):
+    template = Template(template)
+    context = Context(context_dict)
+    return template.render(context)

tests/test_utils_forms.py

@@ -0,0 +1,34 @@
+# passerelle - uniform access to multiple data sources and services
+# Copyright (C) 2023 Entr'ouvert
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import pytest
+from django.core.exceptions import ValidationError
+
+from passerelle.utils.forms import ConditionField, TemplateField
+
+
+def test_condition_field():
+    field = ConditionField()
+    with pytest.raises(ValidationError):
+        field.clean('x ==')
+    assert field.clean('x == 1') == 'x == 1'
+
+
+def test_template_field():
+    field = TemplateField()
+    with pytest.raises(ValidationError):
+        field.clean('{% if foo %}bar')
+    assert field.clean('{% if foo %}bar{% endif %}') == '{% if foo %}bar{% endif %}'

tests/test_utils_templates.py

@@ -0,0 +1,26 @@
+# passerelle - uniform access to multiple data sources and services
+# Copyright (C) 2023 Entr'ouvert
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from passerelle.utils.templates import evaluate_condition, evaluate_template
+
+
+def test_evaluate_condition():
+    assert evaluate_condition('x == 1', {'x': 1}) is True
+    assert evaluate_condition('x == 0', {'x': 1}) is False
+
+
+def test_evaluate_template():
+    assert evaluate_template('{% if foo %}bar{% endif %}', {'foo': True}) == 'bar'