ivelum / djangoql

Advanced search language for Django
MIT License
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DjangoQL

.. image:: https://github.com/ivelum/djangoql/workflows/Tests/badge.svg :target: https://github.com/ivelum/djangoql/actions?query=workflow%3ATests

Advanced search language for Django, with auto-completion. Supports logical operators, parenthesis, table joins, and works with any Django model. Tested on Python 2.7, 3.6 - 3.12, Django 1.8 - 5.0. The auto-completion feature has been tested in Chrome, Firefox, Safari, IE9+.

See a video: DjangoQL demo <https://youtu.be/oKVff4dHZB8>_

.. image:: https://raw.githubusercontent.com/ivelum/djangoql/master/djangoql/static/djangoql/img/completion_example_scaled.png

DjangoQL is used by:

|logo1| |logo2| |logo3| |logo4|

.. |logo1| image:: https://raw.githubusercontent.com/ivelum/djangoql/master/assets/redhat.svg :width: 22% :target: https://www.redhat.com

.. |logo2| image:: https://raw.githubusercontent.com/ivelum/djangoql/master/assets/teamplify.svg :width: 22% :target: https://teamplify.com

.. |logo3| image:: https://raw.githubusercontent.com/ivelum/djangoql/master/assets/police1.svg :width: 22% :target: https://www.police1.com

.. |logo4| image:: https://raw.githubusercontent.com/ivelum/djangoql/master/assets/15-five.svg :width: 22% :target: https://www.15five.com

Is your project using DjangoQL? Please submit a PR and let us know!

Contents

Installation

.. code:: shell

$ pip install djangoql

Add 'djangoql' to INSTALLED_APPS in your settings.py:

.. code:: python

INSTALLED_APPS = [
    ...
    'djangoql',
    ...
]

Add it to your Django admin

Adding DjangoQLSearchMixin to your model admin will replace the standard Django search functionality with DjangoQL search. Example:

.. code:: python

from django.contrib import admin

from djangoql.admin import DjangoQLSearchMixin

from .models import Book

@admin.register(Book)
class BookAdmin(DjangoQLSearchMixin, admin.ModelAdmin):
    pass

Using DjangoQL with the standard Django admin search

DjangoQL will recognize if you have defined search_fields in your ModelAdmin class, and doing so will allow you to choose between an advanced search with DjangoQL and a standard Django search (as specified by search fields). Example:

.. code:: python

@admin.register(Book)
class BookAdmin(DjangoQLSearchMixin, admin.ModelAdmin):
    search_fields = ('title', 'author__name')

For the example above, a checkbox that controls search mode will appear near the search input. If the checkbox is on, then DjanqoQL search is used. There is also an option that controls if that checkbox is enabled by default - djangoql_completion_enabled_by_default (set to True by default):

.. code:: python

@admin.register(Book)
class BookAdmin(DjangoQLSearchMixin, admin.ModelAdmin):
    search_fields = ('title', 'author__name')
    djangoql_completion_enabled_by_default = False

If you don't want two search modes, simply remove search_fields from your ModelAdmin class.

Language reference

DjangoQL is shipped with comprehensive Syntax Help, which can be found in Django admin (see the Syntax Help link in auto-completion popup). Here's a quick summary:

DjangoQL's syntax resembles Python's, with some minor differences. Basically you just reference model fields as you would in Python code, then apply comparison and logical operators and parenthesis. DjangoQL is case-sensitive.

DjangoQL Schema

Schema defines limitations - what you can do with a DjangoQL query. If you don't specify any schema, DjangoQL will provide a default schema for you. This will walk recursively through all model fields and relations and include everything it finds in the schema, so users would be able to search through everything. Sometimes this is not what you want, either due to DB performance or security concerns. If you'd like to limit search models or fields, you should define a schema. Here's an example:

.. code:: python

class UserQLSchema(DjangoQLSchema):
    exclude = (Book,)
    suggest_options = {
        Group: ['name'],
    }

    def get_fields(self, model):
        if model == Group:
            return ['name']
        return super(UserQLSchema, self).get_fields(model)

@admin.register(User)
class CustomUserAdmin(DjangoQLSearchMixin, UserAdmin):
    djangoql_schema = UserQLSchema

In the example above we created a schema that does 3 things:

An important note about suggest_options: it looks for the choices model field parameter first, and if it's not specified - it will synchronously pull all values for given model fields, so you should avoid large querysets there. If you'd like to define custom suggestion options, see below.

Custom search fields

Deeper search customization can be achieved with custom search fields. Custom search fields can be used to search by annotations, define custom suggestion options, or define fully custom search logic. In djangoql.schema, DjangoQL defines the following base field classes that you may subclass to define your own behavior:

Here are examples for common use cases:

Search by queryset annotations:

.. code:: python

from djangoql.schema import DjangoQLSchema, IntField

class UserQLSchema(DjangoQLSchema):
    def get_fields(self, model):
        fields = super(UserQLSchema, self).get_fields(model)
        if model == User:
            fields += [IntField(name='groups_count')]
        return fields

@admin.register(User)
class CustomUserAdmin(DjangoQLSearchMixin, UserAdmin):
    djangoql_schema = UserQLSchema

    def get_queryset(self, request):
        qs = super(CustomUserAdmin, self).get_queryset(request)
        return qs.annotate(groups_count=Count('groups'))

Let's take a closer look at what's happening in the example above. First, we add groups_count annotation to the queryset that is used by Django admin in the CustomUserAdmin.get_queryset() method. It would contain the number of groups a user belongs to. As our queryset now pulls this column, we can filter by it. It just needs to be included in the schema. In UserQLSchema.get_fields() we define a custom integer search field for the User model. Its name should match the name of the column in our queryset.

Custom suggestion options

.. code:: python

from djangoql.schema import DjangoQLSchema, StrField

class GroupNameField(StrField):
    model = Group
    name = 'name'
    suggest_options = True

    def get_options(self, search):
        return super(GroupNameField, self)\
            .get_options(search)\
            .annotate(users_count=Count('user'))\
            .order_by('-users_count')

class UserQLSchema(DjangoQLSchema):
    def get_fields(self, model):
        if model == Group:
            return ['id', GroupNameField()]
        return super(UserQLSchema, self).get_fields(model)

@admin.register(User)
class CustomUserAdmin(DjangoQLSearchMixin, UserAdmin):
    djangoql_schema = UserQLSchema

In this example we've defined a custom GroupNameField that sorts suggestions for group names by popularity (no. of users in a group) instead of default alphabetical sorting.

Custom search lookup

DjangoQL base fields provide two basic methods that you can override to substitute either search column, search value, or both - .get_lookup_name() and .get_lookup_value(value):

.. code:: python

class UserDateJoinedYear(IntField):
    name = 'date_joined_year'

    def get_lookup_name(self):
        return 'date_joined__year'

class UserQLSchema(DjangoQLSchema):
    def get_fields(self, model):
        fields = super(UserQLSchema, self).get_fields(model)
        if model == User:
            fields += [UserDateJoinedYear()]
        return fields

@admin.register(User)
class CustomUserAdmin(DjangoQLSearchMixin, UserAdmin):
    djangoql_schema = UserQLSchema

In this example we've defined the custom date_joined_year search field for users, and used the built-in Django __year filter option in .get_lookup_name() to filter by date year only. Similarly you can use .get_lookup_value(value) hook to modify a search value before it's used in the filter.

Fully custom search lookup

.get_lookup_name() and .get_lookup_value(value) hooks cover many simple use cases, but sometimes they're not enough and you want a fully custom search logic. In such cases you can override main .get_lookup() method of a field. Example below demonstrates User age search:

.. code:: python

from djangoql.schema import DjangoQLSchema, IntField

class UserAgeField(IntField):
    """
    Search by given number of full years
    """
    model = User
    name = 'age'

    def get_lookup_name(self):
        """
        We'll be doing comparisons vs. this model field
        """
        return 'date_joined'

    def get_lookup(self, path, operator, value):
        """
        The lookup should support with all operators compatible with IntField
        """
        if operator == 'in':
            result = None
            for year in value:
                condition = self.get_lookup(path, '=', year)
                result = condition if result is None else result | condition
            return result
        elif operator == 'not in':
            result = None
            for year in value:
                condition = self.get_lookup(path, '!=', year)
                result = condition if result is None else result & condition
            return result

        value = self.get_lookup_value(value)
        search_field = '__'.join(path + [self.get_lookup_name()])
        year_start = self.years_ago(value + 1)
        year_end = self.years_ago(value)
        if operator == '=':
            return (
                Q(**{'%s__gt' % search_field: year_start}) &
                Q(**{'%s__lte' % search_field: year_end})
            )
        elif operator == '!=':
            return (
                Q(**{'%s__lte' % search_field: year_start}) |
                Q(**{'%s__gt' % search_field: year_end})
            )
        elif operator == '>':
            return Q(**{'%s__lt' % search_field: year_start})
        elif operator == '>=':
            return Q(**{'%s__lte' % search_field: year_end})
        elif operator == '<':
            return Q(**{'%s__gt' % search_field: year_end})
        elif operator == '<=':
            return Q(**{'%s__gte' % search_field: year_start})

    def years_ago(self, n):
        timestamp = now()
        try:
            return timestamp.replace(year=timestamp.year - n)
        except ValueError:
            # February 29
            return timestamp.replace(month=2, day=28, year=timestamp.year - n)

class UserQLSchema(DjangoQLSchema):
    def get_fields(self, model):
        fields = super(UserQLSchema, self).get_fields(model)
        if model == User:
            fields += [UserAgeField()]
        return fields

@admin.register(User)
class CustomUserAdmin(DjangoQLSearchMixin, UserAdmin):
    djangoql_schema = UserQLSchema

Can I use it outside of Django admin?

Sure. You can add DjangoQL search functionality to any Django model using DjangoQLQuerySet:

.. code:: python

from django.db import models

from djangoql.queryset import DjangoQLQuerySet

class Book(models.Model):
    name = models.CharField(max_length=255)
    author = models.ForeignKey('auth.User')

    objects = DjangoQLQuerySet.as_manager()

With the example above you can perform a search like this:

.. code:: python

qs = Book.objects.djangoql(
    'name ~ "war" and author.last_name = "Tolstoy"'
)

It returns a normal queryset, so you can extend it and reuse if necessary. The following code works fine:

.. code:: python

print(qs.count())

Alternatively you can add DjangoQL search to any existing queryset, even if it's not an instance of DjangoQLQuerySet:

.. code:: python

from django.contrib.auth.models import User

from djangoql.queryset import apply_search

qs = User.objects.all()
qs = apply_search(qs, 'groups = None')
print(qs.exists())

Schemas can be specified either as a queryset option, or passed to .djangoql() queryset method directly:

.. code:: python

class BookQuerySet(DjangoQLQuerySet):
    djangoql_schema = BookSchema

class Book(models.Model):
    ...

    objects = BookQuerySet.as_manager()

# Now, Book.objects.djangoql() will use BookSchema by default:
Book.objects.djangoql('name ~ "Peace")  # uses BookSchema

# Overriding default queryset schema with AnotherSchema:
Book.objects.djangoql('name ~ "Peace", schema=AnotherSchema)

You can also provide schema as an option for apply_search()

.. code:: python

qs = User.objects.all()
qs = apply_search(qs, 'groups = None', schema=CustomSchema)

Using completion widget outside of Django admin

The completion widget is not tightly coupled to Django admin, so you can easily use it outside of the admin if you want. The widget is available on npm <https://www.npmjs.com/package/djangoql-completion> as a standalone package. See the source code and the docs in the djangoql-completion <https://github.com/ivelum/djangoql-completion> repo on GitHub.

The completion widget is also bundled with the djangoql <https://pypi.org/project/djangoql/>_ Python package on PyPI. If you're not using Webpack or another JavaScript bundler, you can use the pre-built version that ships with the Python package. Here is an example:

Template code, completion_demo.html:

.. code:: html

{% load static %}
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>DjangoQL completion demo</title>
  <link rel="stylesheet" type="text/css" href="https://github.com/ivelum/djangoql/blob/master/{% static 'djangoql/css/completion.css' %}" />
  <script src="https://github.com/ivelum/djangoql/raw/master/{% static 'djangoql/js/completion.js' %}"></script>
</head>
<body>

  <form action="" method="get">
    <p style="color: red">{{ error }}</p>
    <textarea name="q" cols="40" rows="1" autofocus>{{ q }}</textarea>
  </form>

  <ul>
  {% for item in search_results %}
    <li>{{ item }}</li>
  {% endfor %}
  </ul>

  <script>
    DjangoQL.DOMReady(function () {
      new DjangoQL({
        // either JS object with a result of DjangoQLSchema(MyModel).as_dict(),
        // or an URL from which this information could be loaded asynchronously
        introspections: {{ introspections|safe }},

        // css selector for query input or HTMLElement object.
        // It should be a textarea
        selector: 'textarea[name=q]',

        // optional, you can provide URL for Syntax Help link here.
        // If not specified, Syntax Help link will be hidden.
        syntaxHelp: null,

        // optional, enable textarea auto-resize feature. If enabled,
        // textarea will automatically grow its height when entered text
        // doesn't fit, and shrink back when text is removed. The purpose
        // of this is to see full search query without scrolling, could be
        // helpful for really long queries.
        autoResize: true
      });
    });
  </script>
</body>
</html>

And in your views.py:

.. code:: python

import json

from django.contrib.auth.models import Group, User
from django.shortcuts import render_to_response
from django.views.decorators.http import require_GET

from djangoql.exceptions import DjangoQLError
from djangoql.queryset import apply_search
from djangoql.schema import DjangoQLSchema
from djangoql.serializers import DjangoQLSchemaSerializer

class UserQLSchema(DjangoQLSchema):
    include = (User, Group)
    suggest_options = {
        Group: ['name'],
    }

@require_GET
def completion_demo(request):
    q = request.GET.get('q', '')
    error = ''
    query = User.objects.all().order_by('username')
    if q:
        try:
            query = apply_search(query, q, schema=UserQLSchema)
        except DjangoQLError as e:
            query = query.none()
            error = str(e)
    # You may want to use SuggestionsAPISerializer and an additional API
    # endpoint (see in djangoql.views) for asynchronous suggestions loading
    introspections = DjangoQLSchemaSerializer().serialize(
      UserQLSchema(query.model),
    )
    return render_to_response('completion_demo.html', {
        'q': q,
        'error': error,
        'search_results': query,
        'introspections': json.dumps(introspections),
    })

License

MIT