Autocomplete definition¶

Here we’ll see how to define Agnocomplete-compatible autocomplete classes.

Where should they live?¶

These classes must live in a module names autocomplete, located in one of your Django INSTALLED_APPS. How you’re organizing these modules is up to you, but the autodiscover feature needs them to be located in this module.

General options¶

Page size¶

The page size parameter can have four different sources. It’s the maximum number of items returned by the autocomplete when you’re being querying it. In order to keep it performant and pertinent, it has limits.

By default, it’s defined by the constants that live in the agnocomplete.constants module:

"Agnocomplete default page size"
AGNOCOMPLETE_DEFAULT_PAGESIZE = 10

"Agnocomplete maximum page size"
AGNOCOMPLETE_MAX_PAGESIZE = 100

"Agnocomplete minimum page size"
AGNOCOMPLETE_MIN_PAGESIZE = 3

You can override these module defaults using your django settings:

# AGNOCOMPLETE specifics
AGNOCOMPLETE_DEFAULT_PAGESIZE = 15
AGNOCOMPLETE_MAX_PAGESIZE = 120
AGNOCOMPLETE_MIN_PAGESIZE = 2

If you need to specify a default / min / max page size for your specific Autocomplete class, you still can do it via a class property:

class AutocompletePerson(AgnocompleteModel):
    page_size = 30
    page_size_max = 120
    page_size_min = 5

Finally, when the HTTP client (usually a JS script, but it can be a curl-like command line tool) is querying, it can add a page_size argument to tailor the page size to its need:

curl http://yourserver/agnocomplete/AutocompletePerson/?q=ali&page_size=3

Note

The minimum and maximum page size can’t be overridden by the client, to avoid performances issues.

Minimum length of query size¶

It’s obvious that searching for a one-character-term is not a good idea, both on the backend side (too many pointless calls) or on the frontend (too many unusable results). To limit this, we advise the front-end integration not to call the agnocomplete URL if the search term typed in the search box doesn’t meet the minimum length.

This is handled by the query_size parameter. As for the page size, this parameter can be overridden, but only in the backend.

There are two important settings:

AGNOCOMPLETE_DEFAULT_QUERYSIZE: the usual default minimum length of the search term to be queried.
AGNOCOMPLETE_MIN_QUERYSIZE: the absolute minimum length of a search term.

These variables are set in the agnocomplete.constants module.

They can be overridden in the django settings, like this:

AGNOCOMPLETE_DEFAULT_QUERYSIZE = 5
AGNOCOMPLETE_MIN_QUERYSIZE = 3

Also, this can be overridden in the autocomplete class definition, like this:

class AutocompletePerson(AgnocompleteModel):
    query_size = 6
    query_size_min = 5

Note

They don’t have to be different, you can also force them to be equal:

AGNOCOMPLETE_DEFAULT_QUERYSIZE = AGNOCOMPLETE_MIN_QUERYSIZE = 3

In the input, we’re providing a data-query-size attribute you can fetch to adjust your frontend.
If the AJAX view is called with a search term that is smaller than the Agnocomplete class minimum length, the resultset will be empty.

AgnocompleteField¶

This basic class provides non-Django-model autocompletion tools. This class is built when your dataset is computed or generated, or a static list of values (like the states of the United States of America, for example).

When you’re deriving this class, you have to provide a choices property. This property is usually a list of valid values.

AgnocompleteModel¶

Choices in this class are related to a Django model. You must provide:

a model property pointing at a Django model class OR a get_queryset() method, returning the raw records, ready to be filtered by the searched terms.,
a fields property listing the fields to be used when searching for a value.

class AutocompletePerson(AgnocompleteModel):
    model = Person
    fields = ['first_name', 'last_name']

class AutocompletePersonQueryset(AgnocompleteModel):
    fields = ['first_name', 'last_name']

    def get_queryset(self):
        return Person.objects.filter(email__contains='example.com')

In this class, when you’ll be searching for “alice”, the returned results will contain this word in the first_name OR the last_name field.

Note

The field searches will be joined using a OR. In our example, the resulting query will be:

SELECT * from demo_people
WHERE first_name ILIKE '%value%' OR last_name ILIKE '%value%'

Fields definition¶

You can define fields using a few tricks to refine your search:

^field_name will look return values that will start with the query argument,
=field_name will look for exact matches for the query argument,
@field_name will use the __search lookup, taking advantage of the full-text search indexes.

Otherwise, the search will be a simple ILIKE '%value%' SQL statement.

User-dependant querysets¶

This section is now handled in the following dedicated document.

see: Context-dependant completions

Customize the label¶

Sometimes, it can be useful to customize the display label. The class provides a method that can be overridden.

For example:

class AutocompletePerson(AgnocompleteModel):
    model = Person
    fields = ['first_name', 'last_name']
    query_size_min = 2

    def label(self, current_item):
        return u'{item} {mail}'.format(
            item=force_text(current_item), mail=current_item.email)

Changed in version 0.7: Prior to that version, the item() method was to be overriden instead.

Extract extra-information¶

You may want to add extra fields to your returned records, fields that belong to another table (e.g. the count of friends each one has). For performance reasons, it’s not safe to extract this out of the raw get_queryset() method. Use the final_queryset property instead, or, better, using the result of the items() serialization.

from django.utils.functional import cached_property

class AutocompletePerson(AgnocompleteModel):
    model = Person
    fields = ['first_name', 'last_name']

    @cached_property
    def friends(self):
        queryset = self.final_queryset
        # This returns a dict of friends count, the keys being the PKs
        return count_friends([item.pk for item in queryset])

    def label(self, current_item):
        friends = self.friends
        return u'{item} {mail} ({friends})'.format(
            item=force_text(current_item),
            mail=current_item.email,
            friends=friends.get(current_item.pk, 0)
        )

Important

The final_queryset property is paginated, which means that you won’t be able to re-paginate it again. For example, this won’t work:

queryset = self.final_queryset.filter(field="something")[:2]

If you need to feed your extra-information with paginated or re-written queries out of the actual one, use final_raw_queryset instead.

queryset = self.final_raw_queryset.filter(field="something")
queryset = queryset[:2]

Using a different field for values¶

New in version 0.7.

As with a standard ModelChoiceField, you may set the to_field_name attribute on AgnocompleteField to use a specific model field for form values instead of the primary key. Be sure to use a unique field for the model.

class SearchForm(forms.Form):
    search_person = fields.AgnocompleteField(
        AutocompletePerson, to_field_name='email')

Extra arguments¶

New in version 0.6.

Your front-end code may send you extra arguments that are not covered by the standard interface definition. These arguments will be passed down to your Agnocomplete class and can be used in the items() or the get_dataset() methods.

class AutocompleteColorExtra(AutocompleteColor):
    def items(self, query, **kwargs):
        extra = kwargs.get('extra_suff', None)
        if extra_stuff:
            change_something_in_the_search_method(extra_stuff)
        return super(AutocompleteColorExtra, self).items(query, **kwargs)

You can also override the get_extra_arguments() method in your views to eventually filter or manipulate these extra arguments. By default, get_extra_arguments() grabs arguments from the GET parameters that are not the query value.

class SelectizeExtraView(AutoView):
    template_name = 'selectize.html'
    title = "View using the Selectize autocomplete front library"
    form = SearchFormExtra

    def get_extra_arguments(self):
        extras = super(SelectizeExtraView, self).get_extra_arguments()
        whitelist = ['foo', 'bar']
        extras = filter(lambda x: x[0] in whitelist, extras)
        return dict(extras)

Everything is possible in the view: you can even push your custom arguments, based on your current context, the date/time, etc.

Important

The result of this method must be a dictionary.

Using Extra arguments with Models/Querysets¶

New in version 0.6.

In the case of a queryset-based Agnocomplete, you can also use the extra arguments in the Agnocomplete class.

The extra arguments are passed along to items(), and then to the build_filtered_queryset() method.

This method calls build_extra_filtered_queryset(). By default, this method returns the queryset “verbatim”. You can override or overwrite this to perform custom filter on this QS.

class AutocompletePersonExtra(AutocompletePerson):

    def build_extra_filtered_queryset(self, queryset, **kwargs):
        location = kwargs.get('location', None)
        if location:
            queryset = queryset.filter(location__iexact=location)
        return queryset

Autocomplete definition¶

Where should they live?¶

General options¶

Page size¶

Minimum length of query size¶

AgnocompleteField¶

AgnocompleteModel¶

Fields definition¶

User-dependant querysets¶

Customize the label¶

Extract extra-information¶

Using a different field for values¶

Extra arguments¶

Using Extra arguments with Models/Querysets¶

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