views.rst

Creating Djata Views

Djata views, by default, support a wide variety of formats and parsers for various REST schemas based on the extension and (in future versions) content negotiation. These can be customized.

For example, to create a custom HTML view for multiple foos, using a template of your own design:

from djata.formats.format_html import
class Foo(View):
    class Meta:
        verbose_name = 'foo'
        verbose_name_plural = 'foos'
    class HtmlModelFormat(HtmlModelFormat):
        template = 'example/foos.html'

The default template for an HtmlModelFormat is djata/model.html, but that too can be overridden for all models by providing an alternate template by the same name earlier in your settings.py TEMPLATE_DIRS list.

You can also create HTML views that respond to different URLs, like fooey.html instead of foos.html:

from djata.formats.format_html import
class Foo(View):
    class Meta:
        verbose_name = 'foo'
        verbose_name_plural = 'foos'
    class FooeyHtmlModelFormat(HtmlModelFormat):
        name = 'fooey.html'
        template = 'example/foos.html'

You can also configure many of the defaults for the view by adding various properties to the Meta metadata class for your view.

• model overrides the model that the view is paired to. By default this is inferred from the models property of the module and the name of the view class.
• verbose_name the name used for single object URLs, that defaults to the verbose_name of the model, which defaults to a lower- case version of the class name.
• verbose_name_plural the name used for multiple object URLs, that defaults to the verbose_name_plural of the model, which in turn defaults to a lower-case version of the class name with an extra "s".
• index determines the name of the field that is used in URLs to select individual objects.
• insecure, if set to True, permits anyone with access to the URL to perform write operations like PUT, POST, and DELETE. The intent is to support Django access control in future versions.
• default_page_length, when set to an integer, turns on pagination with a particular number of objects per page.
• max_page_length permits the user to specify any page length on a URL up to this value.
• default_page_number, dictates the page that viewers first see. The default is 1. -1 shows the last page first.
• visible, if set to False, causes the view to not appear on the automatically generated view index.
• abstract, when set to True, tells Djata to ignore the class. This is useful for base classes that are not associated with any particular model and are not intended to be complete views.
• default_format is the extension of the format to use for the view by default. If it is not specified, it checks for a variable by the same name on the views module. If neither the class or module specify a format, requesting on a URL for the model without providing a format extension will result in a "No format specified error".
• objects and fields, compatible with the corresponding properties of a model, may be provided as an alternative to using Django storage. objects.get(pk), fields.rel.to.objects.get(pk), fields.name, and fields.value_from_object(object) must be supported.
• include_fields white-lists certain fields by name. No others will be available.
• exclude_fields black-lists certain fields by name. All others will be available.
• exclude_methods black lists any set of GET, PUT, POST, DELETE
• exclude_actions black lists any set of read, write, add, change, delete
• exclude_model_formats
• exclude_object_formats
• exclude_model_parsers
• exclude_object_parsers
• exclude_model_pages
• exclude_object_pages

The djata.views.ViewBase supports all the features of a View class but does not support any formats. This is a good base class for any view where you want absolute control.

The djata.views.View base class supports the following formatters and parsers:

• formats:

-- multiple objects (models): --- .json formats.format_json.JsonModelFormat --- .jsonp formats.format_json.JsonpModelFormat --- .html formats.format_html.HtmlModelFormat --- .basic.html formats.format_html.HtmlModelFormat --- .raw.html formats.format_html.RawHtmlModelFormat --- .upload.html formats.format_html.UploadHtmlModelFormat --- .text formats.format_text.TextModelFormat --- .txt formats.format_text.TextModelFormat --- .csv formats.format_csv.CsvModelFormat --- .xls formats.format_xls.XlsModelFormat (if pyExcelerator is -- installed) -- single objects: --- .html formats.format_html.HtmlObjectFormat --- .basic.html formats.format_html.HtmlObjectFormat --- .raw.html formats.format_html.RawHtmlobjectFormat --- .text formats.format_text.TextObjectFormat --- .txt formats.format_text.TextObjectFormat --- .urlencoded formats.format_url.UrlencodedObjectFormat - parsers: -- multiple objects (model): --- .csv formats.format_csv.CsvModelParser -- single objects: --- .urlencoded formats.format_url.UrlencodedObjectParser --- .urlquery formats.format_url.UrlqueryObjectParser

See formats for information on how to create or customize formatter and parsers classes.

Under the Hood

When you create a view class, the ViewMetaclass instantiates your subtype. In the process, it inspects the class's __module__, the module name of the module in which the module was declared. It uses this to discover or create a views property on the module object, an instance of djata.views.Views, which manages URL routing and indexing for all views. You can provide an alternate views instance before your first View class declaration.