django-contactme is a simple reusable app. This is a tutorial as simple as the app itself.
Installing django-contactme is just a matter of checking out the package and adding it to your project or
- Use git to clone the repository, and then install the package (read more about git):
git clone git://github.com/danirus/django-contactme.gitand
python setup.py install
- Or use pip (read more about pip):
pip install django-contactme
- Or use easy_install (read more about easy_install):
url(r'^contact/', include('django_contactme.urls'))to your
- Create a
django_contactmedirectory in your templates directory and copy the default templates from django-contactme into the new created directory.
python manage.py migratethat creates the
- Optionally you can add some settings to control django-contactme behaviour (see Settings), but they all have sane defaults.
- Customize the templates (see Templates) in your
django_contactmetemplates directory to make them fit in your design. Look at the crispy_forms_demo to see an example of templates customisation.
Workflow described in 3 actions:
- Get the Contact Form.
- Render the Contact Form page. Omit this at will by using the
render-contact-formtemplatetag (see Templatetags) in your own templates.
- Post the Contact Form.
- Check if there are form security errors. django_contactme forms are protected with
honeypotfield, following the same approach as the built-in Django Comments Framework. In case of form security errors send a 400 code response and stop.
- Check whether there are other form errors (fields
message) or whether the user clicked on the preview button. In such a case render the Contact Form again, with the form errors if any, and stop.
- Send signal
django_contactme.signals.confirmation_will_be_requested. If any receiver returns
False, send a discarded contact message response to the user and stop.
- Send a confirmation email to the user with a confirmation URL.
- Send signal
- Render a “confirmation has been sent to you by email” template.
- Visit the Confirmation URL.
- Check whether the token in the confirmation URL is correct. If it isn’t raise a 404 code response and stop.
- Create a
ContactMsgmodel instance with the message data secured in the URL.
- Send signal
confirmation_received. If any receiver return False, send a discarded contact message response to the user and stop.
- Send an email to
settings.CONTACTME_NOTIFY_TOaddresses indicating that a new Contact Message has been received.
- Render a “your contact request has been received, thank you” template.
Creating the secure token for the confirmation URL¶
The Confirmation URL sent by email to the user has a secured token with the contact form data. To create the token django-contactme uses the module
signed.py authored by Simon Willison and provided in Django-OpenID.
django_openid.signed offers two high level functions:
- dumps: Returns URL-safe, sha1 signed base64 compressed pickle of a given object.
- loads: Reverse of dumps(), raises ValueError if signature fails.
A brief example:
>>> signed.dumps("hello") 'UydoZWxsbycKcDAKLg.QLtjWHYe7udYuZeQyLlafPqAx1E' >>> signed.loads('UydoZWxsbycKcDAKLg.QLtjWHYe7udYuZeQyLlafPqAx1E') 'hello' >>> signed.loads('UydoZWxsbycKcDAKLg.QLtjWHYe7udYuZeQyLlafPqAx1E-modified') BadSignature: Signature failed: QLtjWHYe7udYuZeQyLlafPqAx1E-modified
There are two components in dump’s output
UydoZWxsbycKcDAKLg.QLtjWHYe7udYuZeQyLlafPqAx1E, separatad by a ‘.’. The first component is a URLsafe base64 encoded pickle of the object passed to dumps(). The second component is a base64 encoded hmac/SHA1 hash of “$first_component.$secret”.
Calling signed.loads(s) checks the signature BEFORE unpickling the object -this protects against malformed pickle attacks. If the signature fails, a ValueError subclass is raised (actually a BadSignature).
Signals and receivers¶
The workflow mentions that django-contactme sends 3 signals:
- confirmation_will_be_requested: Sent just before a confirmation message is requested.
- confirmation_requested: Sent just after a confirmation message is requested.
- confirmation_received: Sent just after a confirmation has been received.
See Signals to know more.
You may want to extend django-contactme by registering a receiver for any of this signals.
An example function receiver might check the datetime a user submitted a contact message and the datetime the confirmation URL has been clicked. If the difference between them is over 7 days the message could be discarded with a graceful “sorry, too old message” template.
Extending the demo site with the following code would do the job:
#---------------------------------------- # append the code below to any demo project views.py module: from datetime import datetime, timedelta from django_contactme import signals def check_submit_date_is_within_last_7days(sender, data, request, **kwargs): plus7days = timedelta(days=7) if data["submit_date"] + plus7days < datetime.now(): return False signals.confirmation_received.connect(check_submit_date_is_within_last_7days) #----------------------------------------------------- # change get_instance_data in django_contactme/forms.py to cheat a bit and # make django believe that the contact form was submitted 7 days ago: def get_instance_data(self): """ Returns the dict of data to be used to create a contact message. """ from datetime import timedelta # ADD THIS return dict( name = self.cleaned_data["name"], email = self.cleaned_data["email"], message = self.cleaned_data["message"], # submit_date = datetime.datetime.now(), # COMMENT THIS submit_date = datetime.datetime.now() - timedelta(days=8), # ADD THIS )
Try the demo site again and see that the django_contactme/discarded.html template is rendered after clicking on the confirmation URL.