Advanced usage examples

Advanced Django REST framework integration examples.

See the example project for sample models/views/serializers.

Contents:

Example app

Sample models

books/models.py:

import json

from django.conf import settings
from django.db import models
from django.utils.translation import ugettext, ugettext_lazy as _

from six import python_2_unicode_compatible

BOOK_PUBLISHING_STATUS_PUBLISHED = 'published'
BOOK_PUBLISHING_STATUS_NOT_PUBLISHED = 'not_published'
BOOK_PUBLISHING_STATUS_IN_PROGRESS = 'in_progress'
BOOK_PUBLISHING_STATUS_CANCELLED = 'cancelled'
BOOK_PUBLISHING_STATUS_REJECTED = 'rejected'
BOOK_PUBLISHING_STATUS_CHOICES = (
    (BOOK_PUBLISHING_STATUS_PUBLISHED, "Published"),
    (BOOK_PUBLISHING_STATUS_NOT_PUBLISHED, "Not published"),
    (BOOK_PUBLISHING_STATUS_IN_PROGRESS, "In progress"),
    (BOOK_PUBLISHING_STATUS_CANCELLED, "Cancelled"),
    (BOOK_PUBLISHING_STATUS_REJECTED, "Rejected"),
)
BOOK_PUBLISHING_STATUS_DEFAULT = BOOK_PUBLISHING_STATUS_PUBLISHED


@python_2_unicode_compatible
class Publisher(models.Model):
    """Publisher."""

    name = models.CharField(max_length=30)
    info = models.TextField(null=True, blank=True)
    address = models.CharField(max_length=50)
    city = models.CharField(max_length=60)
    state_province = models.CharField(max_length=30)
    country = models.CharField(max_length=50)
    website = models.URLField()

    class Meta(object):
        """Meta options."""

        ordering = ["id"]

    def __str__(self):
        return self.name


@python_2_unicode_compatible
class Author(models.Model):
    """Author."""

    salutation = models.CharField(max_length=10)
    name = models.CharField(max_length=200)
    email = models.EmailField()
    headshot = models.ImageField(upload_to='authors', null=True, blank=True)

    class Meta(object):
        """Meta options."""

        ordering = ["id"]

    def __str__(self):
        return self.name


class Tag(models.Model):
    """Simple tag model."""

    title = models.CharField(max_length=255, unique=True)

    class Meta(object):
        """Meta options."""

        verbose_name = _("Tag")
        verbose_name_plural = _("Tags")

    def __str__(self):
        return self.title


@python_2_unicode_compatible
class Book(models.Model):
    """Book."""

    title = models.CharField(max_length=100)
    description = models.TextField(null=True, blank=True)
    summary = models.TextField(null=True, blank=True)
    authors = models.ManyToManyField('books.Author', related_name='books')
    publisher = models.ForeignKey(Publisher, related_name='books')
    publication_date = models.DateField()
    state = models.CharField(max_length=100,
                             choices=BOOK_PUBLISHING_STATUS_CHOICES,
                             default=BOOK_PUBLISHING_STATUS_DEFAULT)
    isbn = models.CharField(max_length=100, unique=True)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    pages = models.PositiveIntegerField(default=200)
    stock_count = models.PositiveIntegerField(default=30)
    tags = models.ManyToManyField('books.Tag',
                                  related_name='books',
                                  blank=True)

    class Meta(object):
        """Meta options."""

        ordering = ["isbn"]

    def __str__(self):
        return self.title

    @property
    def publisher_indexing(self):
        """Publisher for indexing.

        Used in Elasticsearch indexing.
        """
        if self.publisher is not None:
            return self.publisher.name

    @property
    def tags_indexing(self):
        """Tags for indexing.

        Used in Elasticsearch indexing.
        """
        return json.dumps([tag.title for tag in self.tags.all()])

Sample document

search_indexes/documents/book.py:

from django_elasticsearch_dsl import DocType, Index, fields
from elasticsearch_dsl import analyzer

from books.models import Book

# Name of the Elasticsearch index
BOOK_INDEX = Index('book')
# See Elasticsearch Indices API reference for available settings
BOOK_INDEX.settings(
    number_of_shards=1,
    number_of_replicas=1
)


html_strip = analyzer(
    'html_strip',
    tokenizer="standard",
    filter=["standard", "lowercase", "stop", "snowball"],
    char_filter=["html_strip"]
)


@BOOK_INDEX.doc_type
class BookDocument(DocType):
    """Book Elasticsearch document."""

    id = fields.IntegerField(attr='id')

    title = fields.StringField(
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword'
            )
        }
    )

    description = fields.StringField(
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword'
            )
        }
    )

    summary = fields.StringField(
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword'
            )
        }
    )

    publisher = fields.StringField(
        attr='publisher_indexing',
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword'
            )
        }
    )

    publication_date = fields.DateField()

    state = fields.StringField(
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword'
            )
        }
    )

    isbn = fields.StringField(
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword'
            )
        }
    )

    price = fields.FloatField()

    pages = fields.IntegerField()

    stock_count = fields.IntegerField()

    tags = fields.StringField(
        attr='tags_indexing',
        analyzer=html_strip,
        fields={
            'raw': fields.StringField(
                analyzer='keyword',
                multi=True
            )
        },
        multi=True
    )

    class Meta(object):
        """Meta options."""

        model = Book  # The model associate with this DocType

Sample serializer

search_indexes/serializers.py:

import json

from rest_framework import serializers

class TagSerializer(serializers.Serializer):
    """Helper serializer for the Tag field of the Book document."""

    title = serializers.CharField()

    class Meta(object):
        """Meta options."""

        fields = ('title',)
        read_only_fields = ('title',)


class BookDocumentSerializer(serializers.Serializer):
    """Serializer for the Book document."""

    id = serializers.SerializerMethodField()

    title = serializers.CharField(read_only=True)
    description = serializers.CharField(read_only=True)
    summary = serializers.CharField(read_only=True)

    publisher = serializers.CharField(read_only=True)
    publication_date = serializers.DateField(read_only=True)
    state = serializers.CharField(read_only=True)
    isbn = serializers.CharField(read_only=True)
    price = serializers.FloatField(read_only=True)
    pages = serializers.IntegerField(read_only=True)
    stock_count = serializers.IntegerField(read_only=True)
    tags = serializers.SerializerMethodField()

    class Meta(object):
        """Meta options."""

        fields = (
            'id',
            'title',
            'description',
            'summary',
            'publisher',
            'publication_date',
            'state',
            'isbn',
            'price',
            'pages',
            'stock_count',
            'tags',
        )
        read_only_fields = fields

    def get_tags(self, obj):
        """Get tags."""
        return json.loads(obj.tags)

Sample view

search_indexes/views.py:

from django_elasticsearch_dsl_drf.constants import (
    LOOKUP_FILTER_TERMS,
    LOOKUP_FILTER_RANGE,
    LOOKUP_FILTER_PREFIX,
    LOOKUP_FILTER_WILDCARD,
    LOOKUP_QUERY_IN,
    LOOKUP_QUERY_EXCLUDE,
)
from django_elasticsearch_dsl_drf.filter_backends import (
    FilteringFilterBackend,
    OrderingFilterBackend,
    SearchFilterBackend,
)
from django_elasticsearch_dsl_drf.views import BaseDocumentViewSet

# Example app models
from search_indexes.documents.book import BookDocument
from search_indxes.serializers import BookDocumentSerializer


class BookDocumentView(BaseDocumentViewSet):
    """The BookDocument view."""

    document = BookDocument
    serializer_class = BookDocumentSerializer
    lookup_field = 'id'
    filter_backends = [
        FilteringFilterBackend,
        OrderingFilterBackend,
        SearchFilterBackend,
    ]
    # Define search fields
    search_fields = (
        'title',
        'description',
        'summary',
    )
    # Define filtering fields
    filter_fields = {
        'id': {
            'field': '_id',
            'lookups': [
                LOOKUP_FILTER_RANGE,
                LOOKUP_QUERY_IN,
            ],
        },
        'publisher': 'publisher.raw',
        'publication_date': 'publication_date',
        'isbn': 'isbn.raw',
        'tags': {
            'field': 'tags',
            'lookups': [
                LOOKUP_FILTER_TERMS,
                LOOKUP_FILTER_PREFIX,
                LOOKUP_FILTER_WILDCARD,
                LOOKUP_QUERY_IN,
                LOOKUP_QUERY_EXCLUDE,
            ],
        },
        'tags.raw': {
            'field': 'tags.raw',
            'lookups': [
                LOOKUP_FILTER_TERMS,
                LOOKUP_FILTER_PREFIX,
                LOOKUP_FILTER_WILDCARD,
                LOOKUP_QUERY_IN,
                LOOKUP_QUERY_EXCLUDE,
            ],
        },
    }
    # Define ordering fields
    ordering_fields = {
        'id': 'id',
        'title': 'title.raw',
        'price': 'price.raw',
        'state': 'state.raw',
        'publication_date': 'publication_date',
    }
    # Specify default ordering
    ordering = ('id', 'title',)

Usage example

Considering samples above, you should be able to perform the search, sorting and filtering actions described below.

Sample queries

Filtering

Let’s assume we have a number of Book documents with the tags (education, politics, economy, biology, climate, environment, internet, technology).

Multiple filter terms are joined with AND.

Filter documents by field

Filter documents by field (state) “published”.

http://127.0.0.1:8080/search/books/?state=published

Filter documents by multiple fields

Filter documents by field (states) “published” and “in_progress”.

http://127.0.0.1:8080/search/books/?state__in=published|in_progress

Filter document by a single field

Filter documents by (field tag) “education”.

http://127.0.0.1:8080/search/books/?tag=education

Filter documents by multiple fields

Filter documents by multiple fields (field tags) “education” and “economy” with use of functional in query filter.

http://127.0.0.1:8080/search/books/?tags__in=education|economy

You can achieve the same effect by specifying multiple fields (tags) “education” and “economy”. Note, that in this case multiple filter terms are joined with OR.

http://127.0.0.1:8080/search/books/?tags=education&tags=economy

If you want the same as above, but joined with AND, add __term to each lookup.

http://127.0.0.1:8080/search/books/?tags__term=education&tags__term=economy

Filter documents by a word part of a single field

Filter documents by a part word part in single field (tags). Word part should match both “technology” and “biology”.

http://127.0.0.1:8080/search/books/?tags__wildcard=*logy
Ordering

The - prefix means ordering should be descending.

Order documents by field (ascending)

Filter documents by field price (ascending).

http://127.0.0.1:8080/search/books/?search=title|lorem&ordering=price

Order documents by field (descending)

Filter documents by field price (descending).

http://127.0.0.1:8080/search/books/?search=title|lorem&ordering=-price

Order documents by multiple fields

If you want to order by multiple fields, use multiple ordering query params. In the example below, documents would be ordered first by field publication_date (descending), then by field price (ascending).

http://127.0.0.1:8080/search/books/?search=title|lorem&ordering=-publication_date&ordering=price