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Framework and generic app for cross-model searches on a single page

Project description

django-appsearch

Framework and generic app for cross-model searches on a single page

Major sections:

Authors

  • Tim Valenta
  • Gaurav Kapoor
  • Steven Klass

Usage

Appsearch integration is composed of a few separate parts. In the simplest default setup, you must at least do the following:

  • Register models with appsearch
  • Call appsearch.autodiscover() (probably somewhere in your project's urls, like the similar admin function)
  • Create your main view where the search page should appear
  • Create a simple template where the search form can be rendered

There are ways to customize the templates, modify the search queryset, etc, which is covered after the basic introduction.

Model registration

Patterned after django.contrib.admin interface, appsearch includes a registry submodule, which contains a ModelSearch class (along the lines of the admin's ModelAdmin), and a default registry object called search.

ModelSearch has a few basic options, the most important of which are search_fields and display_fields.

We'll use this example base model for registration, which reaches out to a couple of other fake models for the sake of demonstration:

# car/models.py

class Car(models.Model):
    year = models.PositiveIntegerField()
    make = models.ForeignKey(CarMake)
    model = models.ForeignKey(CarModel)

    owners = models.ManyToManyField(User)

    nickname = models.CharField(max_length=50)
    adoption_story = models.TextField()
search_fields

To register this model, place a search.py submodule in your app's directory and include at least this basic registration code. We'll leave out the majority of Car's fields for clarity:

# car/search.py

from appsearch.registry import ModelSearch, search
from project.car.models import Car

class CarSearch(ModelSearch):
    search_fields = (
        'year',
        'nickname',
        'adoption_story',
    )

search.register(Car, CarSearch)

search_fields is an iterable whose items describe searchable fields. The order that the fields are listed here will be respected in the appsearch UI. An item in the list can be a string if it directly describes a model field name. The field will be looked up and its verbose_name stored for use in the UI. To explicitly declare a "verbose name" for use within the appsearch UI, you can make the string a 2-tuple of the verbose name and the field name:

search_fields = (
    'year',
    ("Name", 'nickname'),
    'adoption_story',
)

To pull related fields into the mix, an item can instead be a single-entry dictionary, mapping the attribute to a nested structure following the same format:

search_fields = (
    'year',
    ("Name", 'nickname'),
    'adoption_story',
    {'make': (
        'name',
    )},
    {'model': (
        'name',
    )},
    {'owners': (
        'username',
        'first_name',
        'last_name',
    )},
)

This syntax reduces potentially repetitive query language such as "owners__username", "owners__first_name", and "owners__last_name".

Any related field that doesn't supply its own verbose name here in the search configuration will be displayed with the related model's verbose_name in front of it. In other words, to prevent the search UI from presenting an owner's "first_name" field as if it were the car's first name, the UI will prefix the field's name with the User model's verbose_name. In this example, first_name would be shown as "User first name".

To prevent the automatic prefix, you can supply your own verbose name as previously shown:

search_fields = (
    # ...
    {'owners': (
        ("Username", 'username'), # would have been "User username"
        ("User's First name", "first_name"), # would have been "User first name"
        ("User's Last name", "last_name"), # would have been "User last name"
    )},
)

Related fields can be nested:

search_fields = (
    # ...
    {'owners': (
        'username', # displayed as "User username"
        {'groups': (
            'name', # displayed as "Group name"
        )},
    )},
)

Another way to specify a related field is to use the related model class itself as the dictionary key. Using this method, the field name will automatically be retrieved by inspecting the relationships between the two models:

    search_fields = (
        # ...
        {User: ( # validated to the string "owner", as in the previous example
            'username', # displayed as "User username"
            {'groups': (
                'name', # displayed as "Group name"
            )},
        )}
    )

Eventually this syntax will be the supported method for accessing generic foreign keys, although such relationships are not yet implemented.

NOTE: Generic models that are referenced by a GenericRelation field (e.g., a Car object with a GenericRelation field called "comments" to a generic Comment model) are considered valid and are digested by the appsearch framework:

search_fields = (
    # ...
    {'comments': ( # Car.comments as a GenericRelation field to Comment model
        'title',
        'content',
    )},
)
display_fields

By default, the results table shown by appsearch will include all local fields on the model. To explicitly declare the field list, your configuration can include another attribute display_fields, which follows a similar format to search_fields:

class CarSearch(ModelSearch):
    display_fields = (
        'nickname',
        'year',
        ("Make", 'make__name'),
        ("Model", 'model__name'),
        ("Owners", 'get_owners_list'), # attribute on the Car model
    )

    search_fields = (
        # ...
    )

display_fields is an iterable of items, either strings or 2-tuples of (verbosename, fieldname). As with search_fields, fields will have their verbose_name automatically retrieved, unless it is supplied explicitly in the configuration.

A field isn't necessarily required to be a database field; in the example above, we've placed an "Owners" column in the table headers, and the field is actually a method name. This is convenient, but be careful not generate too many queries outside of appsearch's control!

The first item in this list will be converted into a link, wrapping the value with a simple snippet of HTML: <a href="{{ object.get_absolute_url }}">{{ value }}</a>

appsearch will examine display_fields to discover how to best issue a select_related() call to the search results queryset, which helps keep the automatic query count low.

appsearch.autodiscover()

As with the built-in admin, appsearch can crawl your apps to discover a search.py module in each one. autodiscover() doesn't do anything but import those configurations and cause them to execute, so if you're using custom or multiple registries, this function will let those registries set themselves up.

As with the admin, a nice place to call autodiscover() is in your urls module, either at the root of your project or in a local "search" app where you are going to set up the view anyway. See the example in the next section.

The main view

You need to declare your own starting point for the client to initially visit and configure a search.

BaseSearchView is a simple TemplateView subclass that also inherits from appsearch.views.SearchMixin. For a completely vanilla behavior, you could include the BaseSearchView directly:

# project/mysearchapp/urls.py

from django.conf.urls.defaults import patterns, url
from appsearch.views import BaseSearchView
import appsearch.autodiscover

appsearch.autodiscover()

urlpatterns = patterns('',
    url(r'^search/$', BaseSearchView.as_view(template_name="search.html")),
)

Remember, because BaseSearchView is pretty much just a TemplateView, you need to give it a template_name value. Don't worry though, since the view inherits machinery for making the search form trivial to render into your custom template.

Alternately, you can of course go and actually subclass BaseSearchView and gain access to extra flexibility:

# project/mysearchapp/views.py

from appsearch.views import BaseSearchView

class SearchView(BaseSearchView):
    template_name = "search.html"

search.html

You're free to make whatever template you want for the search to exist on. By default, all you need to do is render the search context variable into your template. Just make sure that jQuery and the appsearch plugin are loaded:

{# search.html #}

{% block javascript %}
    <script type="text/javascript" src="{{ STATIC_URL }}js/jquery-1.8.3.min.js"></script>
    <script type="text/javascript" src="{{ STATIC_URL }}js/jquery.appsearch.js"></script>
{% endblock %}

{% block content %}
    {{ search }}
{% endblock %}

There are plenty of ways to customize how the form is rendered and how the Javascript behaves, but this is enough to get a fully functioning search implementation.

That's it!

With the ajax urls mounted, your instance of BaseSearchView in play, and your model configurations registered, and your template dumping out the generated form, you're finished.

API

ModelSearch

appsearch.registry.ModelSearch

The base configuration class used to register a model for search discovery.

verbose_name

If provided, the model that is registered with this ModelSearch instance will take on this verbose name, hiding the model's own verbose_name option.

Default: The registered model's verbose_name

verbose_name_plural

If provided, the model that is registered with this ModelSearch instance will take on this plural verbose name, hiding the model's own verbose_name option.

Default: The plural of the configuration's verbose_name, if available, or else the model class's verbose_name_plural.

display_fields

An iterable of column description items.

Each "item" can be a string:

'field_name'

or a 2-tuple where the verbose name is explicitly supplied:

("My field name", 'field_name')

In either case, the field name can refer to a local field (including a method name), or a queryset-style lookup path. In the latter case, an explicit verbose name should be supplied:

("Related field name", 'relationship__field_name')

Any cross-model lookups will be automatically detected and the appropriate .select_related() statement will be issued.

Default: All local fields

search_fields

An iterable of field description items.

Each "item" can be a string describing a local database field:

'field_name'

or a 2-tuple where the verbose name is explicitly supplied:

("My field name", 'field_name')

or a single-item dictionary mapping a related accessor to a new iterable of related field description items following the same format rules:

{'users': (
    # strings, 2-tuples, or more nested single-item dictionaries
)}

The order in which search_fields are declared will be respected by the search form UI.

For related fields inside of a dictionary item, verbose names will be prefixed with the field's model's verbose_name:

{'users': (
    'username', # displays User's verbose name + User.username's verbose name: "User username"
)}

The prefix will not be added if the field already explicitly declares a verbose name:

{'users': (
    ("Username", 'username'), # displays "Username" only
)}

get_queryset(user)

Returns the base queryset that searches on this model will use to apply the generated query. By default the model's default manager is used to return an unfiltered queryset. An appropriate use of this hook would be to use a different manager, or to limit the queryset based on a permission mechanism.

user is the user issuing the request.

get_object_data(obj)

Given a search result object obj, return a list of data fields for the frontend table. The length of the list should match the number of display columns.

The default implementation will automatically read the attributes specified in the configuration's display_fields and build this list. If a value is callable, it will be called with no arguments and the return value used in its place, allowing display_fields to specify instance attributes and methods, along with concrete database-backed fields.

The work done by the default search mechanism will attempt to call select_related() on the source queryset before this method is called on each result object, but be careful not to generate excessive queries per object. If additional related fields need to be selected to avoid high query counts, you can supply your own subclass of Searcher and either:

  1. Override Searcher.build_queryset() method, calling super() and performing extra select_related() calls on the return value.
  2. Override get_select_related_fields() directly and adding to the list.

SearchRegistry

appsearch.registry.SearchRegistry

The registry container where configurations are stored for use in the search form.

The default registry is made available in the module variable called search.

__iter__()

Yields the registration keys, which are strings in the form "applabel.modelname".

__getitem__(k)

If k is a model class, the registration key is generated ("applabel.modelname") in its place. Otherwise, k is directly used to look up a model configuration in the registry.

__contains__(k)

If k is a model class, the registration key is generated ("applabel.modelname") in its place. Otherwise, k is directly used to test membership in the registry.

register(model, configuration)

Registers a model class model with the given configuration class.

get_configuration(model)

Returns the configuration instance associated with model.

get_configurations([user[, permission]])

Returns the configurations in sorted order.

If user is specified, configurations will be included only if the user has the built-in "applabel.change_modelname" permission on the associated model class.

If permission is also supplied, it should be a string with two string-formatting positions for the applabel and the modelname, such as "{}.add_{}" or {}.manage_{}.

set_sort_function(f)

f should be a function that accepts a parameter configurations and returns the configurations in the desired order. The default sort function arranges the configurations based on their verbose_name attributes.

Searcher

appsearch.utils.Searcher

The object wrapping all data necessary to render the search UI and execute the search itself. The current instance is sent to the form template context, by default with the name "search".

The Searcher class can be specified by the instance of the BaseSearchView producing the main search page.

form_template_name

Default: "appsearch/default_form.html"

Normally the view that builds the Searcher instance will supply its own template name, but in the event that the view's value is explicitly set to None, or the Searcher is being custom constructed, this value will be used.

search_form_template_name

Default: "appsearch/search_form.html"

Same as form_template_name.

results_list_template_name

Default: "appsearch/results_list.html"

Same as form_template_name.

__unicode__()

Renders the template name at self.form_template_name.

This default template automatically calls render_search_form() and render_results_list(), making it the simplest way to generate the appsearch UI.

render_search_form()

Renders the template name at self.search_form_template_name.

This generates the HTML for the forms, not including the results list.

render_results_list()

Renders the template name at self.results_list_template_name.

This generates the HTML for the results list, not including the forms. This result is empty if the search was not executed during the current request.

model_selection_form

An instance of appsearch.forms.ModelSelectionForm.

constraint_formset

An instance of appsearch.forms.ConstraintFormset, containing appsearch.forms.ConstraintForm instances.

field_data_url

The URL the appsearch Javascript should use to fetch the list of searchable fields for a given model once a selection has been made on model_selection_form. The URL is derived at construction time by reversing the default URL name "appsearch:constraint-fields", optionally including the prefix designated at construction time, sent in by the view building the Searcher out of the keyword arguments returned by BaseSearchView.get_searcher_kwargs().

operator_data_url

Like field_data_url, the URL the appsearch Javascript should use to fetch the list of valid operators for the model and field combination selected on the UI.

ready

A read-only flag for determining if a search can be performed. ready is only True if both the model selection form and the constraint formset pass the normal is_valid() checks.

model

Only available after ready is checked and model_selection_form can have its selected model determined. The model class that the search will operator on.

model_config

Only available after ready is checked, like model. The configuration ModelSearch instance associated with the selected model class.

results

A dictionary of result data available after ready is True and the view had consequently generated the final search query and executed it. The results dictionary is used exclusively in the templates to render the UI table with the column headers and row data.

results['count']

The length of the result queryset.

results['list']

The iterable list of data rows. Each "row" is represented by a list of column data for the UI table. The results list is made up of the return values of ModelSearch.get_object_data().

results['fields']

The list of verbose names to represent the fields designated by the model's ModelSearch.display_fields list.

results['natural_string']

A string built using the constraint formset options, built with a prefix string "where" and joining each constraint form with a comma. The result is a string in the format:

"where {verbosename1} {operator1} {value1}, {verbosename2} {operator2} {value2}"

build_queryset(model, query[, queryset=None])

When the forms are valid and the search will be performed, this method applies the query object (a combination of django.db.models.query.Q instances) to the model class. This method takes care to also select the necessary related fields that the model configuration will show via ModelSearch.display_fields.

This can serve as a hook for the Searcher object to make final modifications to the query, regardless of the model class. Most queryset modifications should take place in each ModelSearch.get_queryset() method, since each model can control its base queryset in a clearer context.

By default, the machinery in appsearch will not pass a queryset argument directly to this method, but if you subclass Searcher and override this method, you may call super() to send this default implementation a base queryset to use in place of the model's default manager queryset. This is appropriate when all searchable models use a common query interface, such as sharing a project-level object manager or permission system.

The return value of this method is the queryset resulting from the model queryset filtered by query.

get_select_related_fields(model, config)

Returns the list of queryset names that will be sent to an eventual call to the model's queryset select_related(). The default list is generated by examining config's display_fields.

SearchMixin

appsearch.views.SearchMixin

Machinery for building a Searcher instance and inserting it into the template context.

searcher_class

Default: Searcher

context_object_name

Default: "search"

The name that the Searcher instance will be given in the template context.

model_selection_form_class

Default: appsearch.forms.ModelSelectionForm

The form that is responsible for the initial model dropdown in the search UI. The default form provides an automatic verification against the registry, provides a ContentType id obfuscation, and defines a couple of methods to retrieve a validated instance's selected model class and associated ModelSearch configuration.

To provide a modified form, make sure it either subclasses ModelSelectionForm or provides the identical API methods get_selected_model() and get_selected_model_configuration().

constraint_form_class

Default: appsearch.forms.ConstraintForm

An instance of this form class represents a row in the constraint builder UI, composed of fields that describe the constraint: the core AND/OR, the field to inspect, the operator, and the term or terms that describe the constraint.

By default, the field and operator fields have an empty choices list, since the choices depend on a valid selection in the model selection form. The frontend Javascript queries the core appsearch AJAX views to look up the appropriate choices from the registry. Consequently, the form's field-cleaning methods verify a valid selection.

All of the constraint form's fields are cleaned and database-ready values are returned. For example, the field type, which describes if the constraint is an AND or OR operation is cleaned to operator.and_ or operator.or_, respectively. Accordingly, the operator field is cleaned to the actual queryset language path(s), such as "related__lookup__path".

constraint_formset_class

Default: appsearch.forms.ConstraintFormset

The formset class used as the basis of formset_factory() creation. The default form overrides an internal method to ensure that the model selection form's corresponding configuration is sent to the constructor of the constraint forms within. It contains no other logic or overrides.

get_model_selection_form_class()

Returns self.model_selection_form_class

get_constraint_form_class()

Returns self.constraint_form_class

get_constraint_formset_class()

Returns self.constraint_formset_class

form_template_name

Default: "appsearch/default_form.html"

This default template includes the contents of the default templates at search_form_template_name and results_list_template_name.

search_form_template_name

Default: "appsearch/search_form.html"

Renders the search forms, not including the search results.

results_list_template_name

Default: "appsearch/results_list.html"

Renders the results list, not including the search forms. The output of the template is blank if no search was executed on the current request.

get_form_template_name()

Returns self.form_template_name

get_search_form_template_name()

Returns self.search_form_template_name

get_results_list_template_name()

Returns self.results_list_template_name

get_searcher_class()

Returns self.searcher_class

get_searcher_kwargs()

Returns a dictionary of keyword arguments to be passed to the searcher constructor. The default kwargs are the template names specified by the view.

get_searcher()

Returns an instantiated searcher, using the class provided by get_searcher_class() and the keyword arguments given by get_searcher_kwargs().

get_context_object_name()

Returns self.context_object_name.

get_context_data(**kwargs)

Adds the Searcher instance to the context via the name given by get_context_object_name()

If the searcher instance reports that it is fully valid, the search will be executed during this method.

BaseSearchView

appsearch.views.BaseSearchView

Inherits from SearchMixin and the built-in TemplateView.

Build Process:

  1. Update the __version_info__ inside of the application. Commit and push.
  2. Tag the release with the version. git tag <version> -m "Release"; git push --tags
  3. Build the release rm -rf dist build *egg-info; python setup.py sdist bdist_wheel
  4. Upload the data twine upload dist/*

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