基本用法

Django REST Elasticsearch提供了集成Django REST Framework和Elasticsearch的簡(jiǎn)便方法。該庫(kù)使用Elasticsearch DSL庫(kù)（elasticsearch-dsl-py）它是官方低級(jí)客戶端的高級(jí)庫(kù)。

讓我們看一下使用Django REST Elasticsearch構(gòu)建一個(gè)簡(jiǎn)單應(yīng)用程序的快速示例。在這個(gè)例子中，我們將構(gòu)建一個(gè)簡(jiǎn)單的博客系統(tǒng)。

要求

• Django REST Framework 3.5及更高版本
• elasticsearch-dsl> = 5.0.0，<7.0.0（Elasticsearch 5.x）

安裝

pip install django-rest-elasticsearch

創(chuàng)建模型

首先，我們創(chuàng)建一個(gè)模型。

class Blog(models.Model):
    title = models.CharField(_('Title'), max_length=1000)
    created_at = models.DateTimeField(_('Created at'), auto_now_add=True)
    body = models.TextField(_('Body'))
    tags = ArrayField(models.CharField(max_length=200), blank=True, null=True)
    is_published = models.BooleanField(_('Is published'), default=False)

    def __str__(self):
        return self.title

在Elasticsearch中創(chuàng)建映射

然后，我們必須圍繞我們的Django模型創(chuàng)建一個(gè)類似于模型的包裝器。

class BlogIndex(DocType):

    pk = Integer()
    title = Text(fields={'raw': Keyword()})
    created_at = Date()
    body = Text()
    tags = Keyword(multi=True)
    is_published = Boolean()

    class Meta:
        index = 'blog'

我們需要在Elasticsearch中創(chuàng)建映射。為此，您可以通過調(diào)用init類方法直接創(chuàng)建映射：

BlogIndex.init()

在文檔生命周期文檔中，您可以找到有關(guān)如何手動(dòng)使用文檔的完整說明。

添加，更新或刪除新數(shù)據(jù)時(shí)使索引可更新

我們希望在ElasticSearch中擁有一致的數(shù)據(jù)，這就是我們?cè)诟哪Ｐ椭械娜魏蝺?nèi)容時(shí)需要?jiǎng)?chuàng)建，更新或刪除文檔的原因。最好的方法是添加一個(gè)Django信號(hào)調(diào)度程序。在添加信號(hào)之前，讓我們創(chuàng)建一個(gè)序列化器來創(chuàng)建，更新和刪除elasticsearch文檔。

from rest_framework_elasticsearch.es_serializer import ElasticModelSerializer
from .models import Blog
from .search_indexes import BlogIndex

class ElasticBlogSerializer(ElasticModelSerializer):
    class Meta:
        model = Blog
        es_model = BlogIndex
        fields = ('pk', 'title', 'created_at', 'tags', 'body', 'is_published')

在我們需要?jiǎng)?chuàng)建signals.py文件并添加此代碼之后：

from django.db.models.signals import pre_save, post_delete
from django.dispatch import receiver
from .serializers import Blog, ElasticBlogSerializer

@receiver(pre_save, sender=Blog, dispatch_uid="update_record")
def update_es_record(sender, instance, **kwargs):
    obj = ElasticBlogSerializer(instance)
    obj.save()

@receiver(post_delete, sender=Blog, dispatch_uid="delete_record")
def delete_es_record(sender, instance, *args, **kwargs):
    obj = ElasticBlogSerializer(instance)
    obj.delete(ignore=404)

簡(jiǎn)單的django REST框架搜索視圖

最后，讓我們創(chuàng)建一個(gè)簡(jiǎn)單的搜索視圖，查找按標(biāo)簽過濾的所有帖子，并按標(biāo)題中的單詞進(jìn)行搜索：

from elasticsearch import Elasticsearch, RequestsHttpConnection
from rest_framework_elasticsearch import es_views, es_pagination, es_filters
from .search_indexes import BlogIndex

class BlogView(es_views.ListElasticAPIView):
    es_client = Elasticsearch(hosts=['elasticsearch:9200/'],
                              connection_class=RequestsHttpConnection)
    es_model = BlogIndex
    es_filter_backends = (
        es_filters.ElasticFieldsFilter,
        es_filters.ElasticSearchFilter
    )
    es_filter_fields = (
        es_filters.ESFieldFilter('tag', 'tags'),
    )
    es_search_fields = (
        'tags',
        'title',
    )

就是這樣，我們可以開始使用它了。

http://example.com/blogs/api/list?search=elasticsearch
http://example.com/blogs/api/list?tag=opensource
http://example.com/blogs/api/list?tag=opensource,aws

分頁(yè)

分頁(yè)響應(yīng)的示例

class BlogView(es_views.ListElasticAPIView):
    es_client = Elasticsearch(hosts=['elasticsearch:9200/'],
                              connection_class=RequestsHttpConnection)

    es_pagination_class = es_pagination.ElasticLimitOffsetPagination

    es_model = BlogIndex
    es_filter_backends = (
        es_filters.ElasticFieldsFilter,
        es_filters.ElasticSearchFilter
    )
    es_filter_fields = (
        es_filters.ESFieldFilter('tag', 'tags'),
    )
    es_search_fields = (
        'tags',
        'title',
    )

排序

排序示例

class BlogView(es_views.ListElasticAPIView):
    es_client = Elasticsearch(hosts=['elasticsearch:9200/'],
                              connection_class=RequestsHttpConnection)

    es_pagination_class = es_pagination.ElasticLimitOffsetPagination

    es_filter_backends = (
        es_filters.ElasticFieldsFilter,
        es_filters.ElasticSearchFilter,
        es_filters.ElasticOrderingFilter,
    )
    es_ordering_fields = (
        "created_at",
        ("title.raw", "title")
    )
    es_filter_fields = (
        es_filters.ESFieldFilter('tag', 'tags'),
    )
    es_search_fields = (
        'tags',
        'title',
    )

https://github.com/myarik/django-rest-elasticsearch