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修改Django Rest Framework中序列化程序的输出

django-rest-framework django python

akaphenom · 技术社区 · 12 年前

我正在使用django-rest框架来输出一篇文章的内容。它运行得很好,只是现在我想修改行为,不返回完整的“内容”,而是一个预告片(比如内容的前200个字符,但理想情况下我希望能够添加任何逻辑,比如200个字符后的第一句话的结尾):

class ArticleSerializer(serializers.HyperlinkedModelSerializer):
    user = UserSerializer(many=False, read_only=True)

    class Meta:
        model = models.Article
        fields = (
            'id'
            ,'title'
            , 'date_added'
            , 'content'
            , 'user'
        )

我查看了GenericAPIView,在那里我认为可能有一些东西需要覆盖——但没有什么看起来很明显——有人能提供一些见解吗?提前谢谢

2 回复 | 直到 12 年前

mariodev 12 年前

我很确定这正是你所需要的:

http://django-rest-framework.org/api-guide/fields.html#serializermethodfield

class ArticleSerializer(serializers.HyperlinkedModelSerializer):
    user = UserSerializer(many=False, read_only=True)
    teaser = serializers.SerializerMethodField('get_teaser')

    class Meta:
        model = models.Article
        fields = (
            'id'
            ,'title'
            , 'date_added'
            , 'user'
            , 'teaser'
        )

    def get_teaser(self, obj):
        return force_text(obj.content[:20])

akaphenom 12 年前

我接受mariodev的解决方案——因为它确实有效,而且是我最初的想法。我确实扩展了我的需求,并希望将预告片功能应用到其他领域,因此我最终得到了:

from django import forms
from rest_framework.compat import force_text
from rest_framework import serializers, fields

class TeaserField(fields.Field):

    def __init__(self, teaser_length=None, original_field=None):
        self.teaser_length = teaser_length
        self.original_field = original_field
        super(fields.Field, self).__init__()

    def field_to_native(self, obj, field_name):
        if(self.original_field != None):
            field_name = self.original_field

        value = getattr(obj, field_name)
        return self.to_native(value)

    def to_native(self, value):
        def joinEm(chunk):
            teaser = ''
            i=0
            while len(teaser) < self.teaser_length:
                teaser += chunk[i] + '.'
                i += 1

            return teaser

        chunk = value.split('.')
        teaser = joinEm(chunk)

        strongOpenTag = '<strong>'
        strongOpen = teaser.find(strongOpenTag)
        strongClose = teaser.find('</strong>')

        if(strongOpen > 0 and strongClose < 0):
            teaser  = teaser.replace(strongOpenTag,'')

        return force_text(teaser)

以前的解决方案

这是我目前的工作解决方案,很想知道对此的意见。

from django import forms
from rest_framework.compat import force_text

class TeaserField(fields.CharField):
    def __init__(self, teaser_length=None, *args, **kwargs):
        self.teaser_length = teaser_length
        super(TeaserField, self).__init__(*args, **kwargs)

    def to_native(self, value):
        return force_text(value[:self.teaser_length])


class ArticleSerializer(serializers.HyperlinkedModelSerializer):
    user = UserSerializer(many=False, read_only=True)
    content = TeaserField(teaser_length=20)
    class Meta:
        model = models.Article
        fields = (
            'id'
            ,'title'
            , 'date_added'
            , 'content'
            , 'user'
        )


class IdeaSerializer(serializers.HyperlinkedModelSerializer):
    user = UserSerializer(many=False, read_only=True)
    teaser = myFields.TeaserField(teaser_length=200, original_field='content')

    class Meta:
        model = myModels.Idea
        fields = (
            'id'
            ,'title'
            , 'date_added'
            , 'user'
            , 'content'
            , 'teaser'
        )