Views & Forms¶
Haystack comes with some default, simple views & forms to help you get started and to cover the common cases. Included is a way to provide:
- Basic, query-only search.
- Search by models.
- Search with basic highlighted results.
- Faceted search.
- Search by models with basic highlighted results.
Most processing is done by the forms provided by Haystack via the
method. As a result, all but the faceted types (see Faceting) use the
There is very little coupling between the forms & the views (other than relying
on the existence of a
search method on the form), so you may interchangeably
use forms and/or views anywhere within your own code.
The most basic of the form types, this form consists of a single field, the
q field (for query). Upon searching, the form will take the cleaned contents
q field and perform an
auto_query on either the custom
SearchQuerySet you provide or off a default
To customize the
SearchQuerySet the form will use, pass it a
searchqueryset parameter to the constructor with the
you’d like to use. If using this form in conjunction with a
the form will receive whatever
SearchQuerySet you provide to the view with
no additional work needed.
SearchForm also accepts a
load_all parameter (
False), which determines how the database is queried when iterating through
the results. This also is received automatically from the
All other forms in Haystack inherit (either directly or indirectly) from this form.
Identical to the
SearchForm except that it tags the
highlight method on
to the end of the
SearchQuerySet to enable highlighted results.
This form adds new fields to form. It iterates through all registered models for
SearchSite and provides a checkbox for each one. If no models
are selected, all types will show up in the results.
Identical to the
ModelSearchForm except that it tags the
method on to the end of the
SearchQuerySet to enable highlighted results on
the selected models.
Identical to the
SearchForm except that it adds a hidden
field onto the form, allowing the form to narrow the results based on the facets
chosen by the user.
Creating Your Own Form¶
The simplest way to go about creating your own form is to inherit from
SearchForm (or the desired parent) and extend the
search method. By
doing this, you save yourself most of the work of handling data correctly and
stay API compatible with the
For example, let’s say you’re providing search with a user-selectable date range associated with it. You might create a form that looked as follows:
from django import forms from haystack.forms import SearchForm class DateRangeSearchForm(SearchForm): start_date = forms.DateField(required=False) end_date = forms.DateField(required=False) def search(self): # First, store the SearchQuerySet received from other processing. sqs = super(DateRangeSearchForm, self).search() if not self.is_valid(): return self.no_query_found() # Check to see if a start_date was chosen. if self.cleaned_data['start_date']: sqs = sqs.filter(pub_date__gte=self.cleaned_data['start_date']) # Check to see if an end_date was chosen. if self.cleaned_data['end_date']: sqs = sqs.filter(pub_date__lte=self.cleaned_data['end_date']) return sqs
This form adds two new fields for (optionally) choosing the start and end dates.
search method, we grab the results from the parent form’s
processing. Then, if a user has selected a start and/or end date, we apply that
filtering. Finally, we simply return the
Haystack comes bundled with three views, the class-based views (
FacetedSearchView) and a traditional functional view (
The class-based views provide for easy extension should you need to alter the
way a view works. Except in the case of faceting (again, see Faceting),
SearchView works interchangeably with all other forms provided by
The functional view provides an example of how Haystack can be used in more traditional settings or as an example of how to write a more complex custom view. It is also thread-safe.
SearchView(template=None, load_all=True, form_class=None, searchqueryset=None, context_class=RequestContext, results_per_page=None)¶
SearchView is designed to be easy/flexible enough to override common
changes as well as being internally abstracted so that only altering a specific
portion of the code should be easy to do.
Without touching any of the internals of the
SearchView, you can modify
which template is used, which form class should be instantiated to search with,
SearchQuerySet to use in the event you wish to pre-filter the results.
Context-style object to use in the response and the
performance optimization to reduce hits on the database. These options can (and
generally should) be overridden at the URLconf level. For example, to have a
custom search limited to the ‘John’ author, displaying all models to search by
and specifying a custom template (
URLconf should look something like:
from django.conf.urls.defaults import * from haystack.forms import ModelSearchForm from haystack.query import SearchQuerySet from haystack.views import SearchView sqs = SearchQuerySet().filter(author='john') # Without threading... urlpatterns = patterns('haystack.views', url(r'^$', SearchView( template='my/special/path/john_search.html', searchqueryset=sqs, form_class=SearchForm ), name='haystack_search'), ) # With threading... from haystack.views import SearchView, search_view_factory urlpatterns = patterns('haystack.views', url(r'^$', search_view_factory( view_class=SearchView, template='my/special/path/john_search.html', searchqueryset=sqs, form_class=ModelSearchForm ), name='haystack_search'), )
SearchView is not thread-safe. Use the
search_view_factory function, which returns thread-safe instances of
By default, if you don’t specify a
form_class, the view will use the
Beyond this customizations, you can create your own
extend/override the following methods to change the functionality.
Generates the actual response to the search.
Relies on internal, overridable methods to construct the response. You generally should avoid altering this method unless you need to change the flow of the methods or to add a new method into the processing.
Instantiates the form the class should use to process the search query.
Optionally accepts a dictionary of parameters that are passed on to the
__init__. You can use this to lightly customize the form.
You should override this if you write a custom form that needs special parameters for instantiation.
Returns the query provided by the user.
Returns an empty string if the query is invalid. This pulls the cleaned query
from the form, via the
q field, for use elsewhere within the
This is used to populate the
query context variable.
Fetches the results via the form.
Returns an empty list if there’s no query to search with. This method relies on the form to do the heavy lifting as much as possible.
Paginates the results appropriately.
In case someone does not want to use Django’s built-in pagination, it should be a simple matter to override this method to do what they would like.
Allows the addition of more context variables as needed. Must return a dictionary whose contents will add to or overwrite the other variables in the context.
Generates the actual HttpResponse to send back to the user. It builds the page, creates the context and renders the response for all the aforementioned processing.
basic_search(request, template='search/search.html', load_all=True, form_class=ModelSearchForm, searchqueryset=None, context_class=RequestContext, extra_context=None, results_per_page=None)¶
basic_search tries to provide most of the same functionality as the
class-based views but resembles a more traditional generic view. It’s both a
working view if you prefer not to use the class-based views as well as a good
starting point for writing highly custom views.
Since it is all one function, the only means of extension are passing in kwargs, similar to the way generic views work.
Creating Your Own View¶
As with the forms, inheritance is likely your best bet. In this case, the
FacetedSearchView is a perfect example of how to extend the existing
SearchView. The complete code for the
FacetedSearchView looks like:
class FacetedSearchView(SearchView): def extra_context(self): extra = super(FacetedSearchView, self).extra_context() if self.results == : extra['facets'] = self.form.search().facet_counts() else: extra['facets'] = self.results.facet_counts() return extra
It updates the name of the class (generally for documentation purposes) and
adds the facets from the
SearchQuerySet to the context as the
variable. As with the custom form example above, it relies on the parent class
to handle most of the processing and extends that only where needed.