Fixed #3025 -- Added auto_id option to Form.__init__(). Thanks, SmileyChris

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4073 bcc190cf-cafb-0310-a4f2-bffc1f526a37

2 files changed, 74 insertions, 1 deletions

diff --git a/django/newforms/forms.py b/django/newforms/forms.py
index e490d0d5f9..6859ba2a37 100644
--- a/django/newforms/forms.py
+++ b/django/newforms/forms.py
@@ -23,8 +23,9 @@ class Form(object):
     "A collection of Fields, plus their associated data."
     __metaclass__ = DeclarativeFieldsMetaclass
 
-    def __init__(self, data=None): # TODO: prefix stuff
+    def __init__(self, data=None, auto_id=False): # TODO: prefix stuff
         self.data = data or {}
+        self.auto_id = auto_id
         self.clean_data = None # Stores the data after clean() has been called.
         self.__errors = None # Stores the errors after clean() has been called.
 
@@ -156,6 +157,10 @@ class BoundField(object):
     errors = property(_errors)
 
     def as_widget(self, widget, attrs=None):
+        attrs = attrs or {}
+        auto_id = self.auto_id
+        if not attrs.has_key('id') and not widget.attrs.has_key('id') and auto_id:
+            attrs['id'] = auto_id
         return widget.render(self._name, self._form.data.get(self._name, None), attrs=attrs)
 
     def as_text(self, attrs=None):
@@ -167,3 +172,16 @@ class BoundField(object):
     def as_textarea(self, attrs=None):
         "Returns a string of HTML for representing this as a <textarea>."
         return self.as_widget(Textarea(), attrs)
+
+    def _auto_id(self):
+        """
+        Calculates and returns the ID attribute for this BoundField, if the
+        associated Form has specified auto_id. Returns an empty string otherwise.
+        """
+        auto_id = self._form.auto_id
+        if auto_id and '%s' in str(auto_id):
+            return str(auto_id) % self._name
+        elif auto_id:
+            return self._name
+        return ''
+    auto_id = property(_auto_id)
diff --git a/tests/regressiontests/forms/tests.py b/tests/regressiontests/forms/tests.py
index 42596b02e0..21bd378f1f 100644
--- a/tests/regressiontests/forms/tests.py
+++ b/tests/regressiontests/forms/tests.py
@@ -973,6 +973,61 @@ u'* This field is required.'
 >>> print p['birthday']
 <input type="text" name="birthday" />
 
+"auto_id" tells the Form to add an "id" attribute to each form element.
+If it's a string that contains '%s', Django will use that as a format string
+into which the field's name will be inserted.
+>>> p = Person(auto_id='id_%s')
+>>> print p.as_ul()
+<ul>
+<li>First name: <input type="text" name="first_name" id="id_first_name" /></li>
+<li>Last name: <input type="text" name="last_name" id="id_last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" id="id_birthday" /></li>
+</ul>
+
+If auto_id is any True value whose str() does not contain '%s', the "id"
+attribute will be the name of the field.
+>>> p = Person(auto_id=True)
+>>> print p.as_ul()
+<ul>
+<li>First name: <input type="text" name="first_name" id="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" id="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" id="birthday" /></li>
+</ul>
+
+If auto_id is any False value, an "id" attribute won't be output unless it
+was manually entered.
+>>> p = Person(auto_id=False)
+>>> print p.as_ul()
+<ul>
+<li>First name: <input type="text" name="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" /></li>
+</ul>
+
+In this example, auto_id is False, but the "id" attribute for the "first_name"
+field is given.
+>>> class PersonNew(Form):
+...     first_name = CharField(widget=TextInput(attrs={'id': 'first_name_id'}))
+...     last_name = CharField()
+...     birthday = DateField()
+>>> p = PersonNew(auto_id=False)
+>>> print p.as_ul()
+<ul>
+<li>First name: <input type="text" id="first_name_id" name="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" /></li>
+</ul>
+
+If the "id" attribute is specified in the Form and auto_id is True, the "id"
+attribute in the Form gets precedence.
+>>> p = PersonNew(auto_id=True)
+>>> print p.as_ul()
+<ul>
+<li>First name: <input type="text" id="first_name_id" name="first_name" /></li>
+<li>Last name: <input type="text" name="last_name" id="last_name" /></li>
+<li>Birthday: <input type="text" name="birthday" id="birthday" /></li>
+</ul>
+
 >>> class SignupForm(Form):
 ...     email = EmailField()
 ...     get_spam = BooleanField()