classify 0.4.1

Installation

$ pip install classify

Usage

$ classify <python.path.to.Class>

This outputs by default to your shell’s pager. However you can also generate an HTML document to get CCBV style pages and even serve that document.

$ classify <python.path.to.Class> --html [--serve [--port]]

Why?

CCBV has long been part of my everyday toolkit for working with Django’s class-based views, it’s a fantastic resource for quick reference. But it only covers Django’s CBVs.

Classify aims to be CCBV for all your Python classes.

An Example

$ classify django.views.generic.CreateView

class CreateView(SingleObjectTemplateResponseMixin, BaseCreateView):
    """
    View for creating a new object instance,
    with a response rendered by template.
    """
    content_type = None
    context_object_name = None
    form_class = None
    http_method_names = [u'get', u'post', u'put', u'delete', u'head', u'options', u'trace']
    initial = {}
    model = None
    pk_url_kwarg = pk
    queryset = None
    response_class = <class 'django.template.response.TemplateResponse'>
    slug_field = slug
    slug_url_kwarg = slug
    success_url = None
    template_name = None
    template_name_field = None
    template_name_suffix = _form

    def __init__(self, **kwargs):
        """
        Constructor. Called in the URLconf; can contain helpful extra
        keyword arguments, and other things.
        """
        # Go through keyword arguments, and either save their values to our
        # instance, or raise an error.
        for key, value in six.iteritems(kwargs):
            setattr(self, key, value)

    @classonlymethod
    def as_view(cls, **initkwargs):
        """
        Main entry point for a request-response process.
        """
        # sanitize keyword arguments
        for key in initkwargs:
            if key in cls.http_method_names:
                raise TypeError("You tried to pass in the %s method name as a "
                                "keyword argument to %s(). Don't do that."
                                % (key, cls.__name__))
            if not hasattr(cls, key):
                raise TypeError("%s() received an invalid keyword %r. as_view "
                                "only accepts arguments that are already "
                                "attributes of the class." % (cls.__name__, key))

        def view(request, *args, **kwargs):
            self = cls(**initkwargs)
            if hasattr(self, 'get') and not hasattr(self, 'head'):
                self.head = self.get
            self.request = request
            self.args = args
            self.kwargs = kwargs
            return self.dispatch(request, *args, **kwargs)

        # take name and docstring from class
        update_wrapper(view, cls, updated=())

        # and possible attributes set by decorators
        # like csrf_exempt from dispatch
        update_wrapper(view, cls.dispatch, assigned=())
        return view

    def dispatch(self, request, *args, **kwargs):
        # Try to dispatch to the right method; if a method doesn't exist,
        # defer to the error handler. Also defer to the error handler if the
        # request method isn't on the approved list.
        if request.method.lower() in self.http_method_names:
            handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
        else:
            handler = self.http_method_not_allowed
        return handler(request, *args, **kwargs)

    def form_invalid(self, form):
        """
        If the form is invalid, re-render the context data with the
        data-filled form and errors.
        """
        return self.render_to_response(self.get_context_data(form=form))

    def form_valid(self, form):
        """
        If the form is valid, redirect to the supplied URL.
        """
        return HttpResponseRedirect(self.get_success_url())

    def form_valid(self, form):
        """
        If the form is valid, save the associated model.
        """
        self.object = form.save()
        return super(ModelFormMixin, self).form_valid(form)

    def get(self, request, *args, **kwargs):
        """
        Handles GET requests and instantiates a blank version of the form.
        """
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        return self.render_to_response(self.get_context_data(form=form))

    def get(self, request, *args, **kwargs):
        self.object = None
        return super(BaseCreateView, self).get(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        if 'view' not in kwargs:
            kwargs['view'] = self
        return kwargs

    def get_context_data(self, **kwargs):
        """
        Insert the single object into the context dict.
        """
        context = {}
        context_object_name = self.get_context_object_name(self.object)
        if context_object_name:
            context[context_object_name] = self.object
        context.update(kwargs)
        return super(SingleObjectMixin, self).get_context_data(**context)

    def get_context_data(self, **kwargs):
        """
        If an object has been supplied, inject it into the context with the
        supplied context_object_name name.
        """
        context = {}
        if self.object:
            context['object'] = self.object
            context_object_name = self.get_context_object_name(self.object)
            if context_object_name:
                context[context_object_name] = self.object
        context.update(kwargs)
        return super(ModelFormMixin, self).get_context_data(**context)

    def get_context_object_name(self, obj):
        """
        Get the name to use for the object.
        """
        if self.context_object_name:
            return self.context_object_name
        elif isinstance(obj, models.Model):
            return obj._meta.object_name.lower()
        else:
            return None

    def get_form(self, form_class):
        """
        Returns an instance of the form to be used in this view.
        """
        return form_class(**self.get_form_kwargs())

    def get_form_class(self):
        """
        Returns the form class to use in this view
        """
        return self.form_class

    def get_form_class(self):
        """
        Returns the form class to use in this view.
        """
        if self.form_class:
            return self.form_class
        else:
            if self.model is not None:
                # If a model has been explicitly provided, use it
                model = self.model
            elif hasattr(self, 'object') and self.object is not None:
                # If this view is operating on a single object, use
                # the class of that object
                model = self.object.__class__
            else:
                # Try to get a queryset and extract the model class
                # from that
                model = self.get_queryset().model
            return model_forms.modelform_factory(model)

    def get_form_kwargs(self):
        """
        Returns the keyword arguments for instantiating the form.
        """
        kwargs = {'initial': self.get_initial()}
        if self.request.method in ('POST', 'PUT'):
            kwargs.update({
                'data': self.request.POST,
                'files': self.request.FILES,
            })
        return kwargs

    def get_form_kwargs(self):
        """
        Returns the keyword arguments for instantiating the form.
        """
        kwargs = super(ModelFormMixin, self).get_form_kwargs()
        kwargs.update({'instance': self.object})
        return kwargs

    def get_initial(self):
        """
        Returns the initial data to use for forms on this view.
        """
        return self.initial.copy()

    def get_object(self, queryset=None):
        """
        Returns the object the view is displaying.

        By default this requires `self.queryset` and a `pk` or `slug` argument
        in the URLconf, but subclasses can override this to return any object.
        """
        # Use a custom queryset if provided; this is required for subclasses
        # like DateDetailView
        if queryset is None:
            queryset = self.get_queryset()

        # Next, try looking up by primary key.
        pk = self.kwargs.get(self.pk_url_kwarg, None)
        slug = self.kwargs.get(self.slug_url_kwarg, None)
        if pk is not None:
            queryset = queryset.filter(pk=pk)

        # Next, try looking up by slug.
        elif slug is not None:
            slug_field = self.get_slug_field()
            queryset = queryset.filter(**{slug_field: slug})

        # If none of those are defined, it's an error.
        else:
            raise AttributeError("Generic detail view %s must be called with "
                                 "either an object pk or a slug."
                                 % self.__class__.__name__)

        try:
            # Get the single item from the filtered queryset
            obj = queryset.get()
        except ObjectDoesNotExist:
            raise Http404(_("No %(verbose_name)s found matching the query") %
                          {'verbose_name': queryset.model._meta.verbose_name})
        return obj

    def get_queryset(self):
        """
        Get the queryset to look an object up against. May not be called if
        `get_object` is overridden.
        """
        if self.queryset is None:
            if self.model:
                return self.model._default_manager.all()
            else:
                raise ImproperlyConfigured("%(cls)s is missing a queryset. Define "
                                           "%(cls)s.model, %(cls)s.queryset, or override "
                                           "%(cls)s.get_queryset()." % {
                                                'cls': self.__class__.__name__
                                        })
        return self.queryset._clone()

    def get_slug_field(self):
        """
        Get the name of a slug field to be used to look up by slug.
        """
        return self.slug_field

    def get_success_url(self):
        """
        Returns the supplied success URL.
        """
        if self.success_url:
            # Forcing possible reverse_lazy evaluation
            url = force_text(self.success_url)
        else:
            raise ImproperlyConfigured(
                "No URL to redirect to. Provide a success_url.")
        return url

    def get_success_url(self):
        """
        Returns the supplied URL.
        """
        if self.success_url:
            url = self.success_url % self.object.__dict__
        else:
            try:
                url = self.object.get_absolute_url()
            except AttributeError:
                raise ImproperlyConfigured(
                    "No URL to redirect to.  Either provide a url or define"
                    " a get_absolute_url method on the Model.")
        return url

    def get_template_names(self):
        """
        Returns a list of template names to be used for the request. Must return
        a list. May not be called if render_to_response is overridden.
        """
        if self.template_name is None:
            raise ImproperlyConfigured(
                "TemplateResponseMixin requires either a definition of "
                "'template_name' or an implementation of 'get_template_names()'")
        else:
            return [self.template_name]

    def get_template_names(self):
        """
        Return a list of template names to be used for the request. May not be
        called if render_to_response is overridden. Returns the following list:

        * the value of ``template_name`` on the view (if provided)
        * the contents of the ``template_name_field`` field on the
          object instance that the view is operating upon (if available)
        * ``<app_label>/<object_name><template_name_suffix>.html``
        """
        try:
            names = super(SingleObjectTemplateResponseMixin, self).get_template_names()
        except ImproperlyConfigured:
            # If template_name isn't specified, it's not a problem --
            # we just start with an empty list.
            names = []

        # If self.template_name_field is set, grab the value of the field
        # of that name from the object; this is the most specific template
        # name, if given.
        if self.object and self.template_name_field:
            name = getattr(self.object, self.template_name_field, None)
            if name:
                names.insert(0, name)

        # The least-specific option is the default <app>/<model>_detail.html;
        # only use this if the object in question is a model.
        if isinstance(self.object, models.Model):
            names.append("%s/%s%s.html" % (
                self.object._meta.app_label,
                self.object._meta.object_name.lower(),
                self.template_name_suffix
            ))
        elif hasattr(self, 'model') and self.model is not None and issubclass(self.model, models.Model):
            names.append("%s/%s%s.html" % (
                self.model._meta.app_label,
                self.model._meta.object_name.lower(),
                self.template_name_suffix
            ))
        return names

    def http_method_not_allowed(self, request, *args, **kwargs):
        logger.warning('Method Not Allowed (%s): %s', request.method, request.path,
            extra={
                'status_code': 405,
                'request': self.request
            }
        )
        return http.HttpResponseNotAllowed(self._allowed_methods())

    def options(self, request, *args, **kwargs):
        """
        Handles responding to requests for the OPTIONS HTTP verb.
        """
        response = http.HttpResponse()
        response['Allow'] = ', '.join(self._allowed_methods())
        response['Content-Length'] = '0'
        return response

    def post(self, request, *args, **kwargs):
        """
        Handles POST requests, instantiating a form instance with the passed
        POST variables and then checked for validity.
        """
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        if form.is_valid():
            return self.form_valid(form)
        else:
            return self.form_invalid(form)

    def post(self, request, *args, **kwargs):
        self.object = None
        return super(BaseCreateView, self).post(request, *args, **kwargs)

    def put(self, *args, **kwargs):
        return self.post(*args, **kwargs)

    def render_to_response(self, context, **response_kwargs):
        """
        Returns a response, using the `response_class` for this
        view, with a template rendered with the given context.

        If any keyword arguments are provided, they will be
        passed to the constructor of the response class.
        """
        response_kwargs.setdefault('content_type', self.content_type)
        return self.response_class(
            request = self.request,
            template = self.get_template_names(),
            context = context,
            **response_kwargs
        )