一. 前言

在开发REST API接口时，视图中做的最主要有三件事：

• 将请求的数据（如JSON格式）转换为模型类对象
• 操作数据库
• 将模型类对象转换为响应的数据（如JSON格式）

序列化：

将程序中的一个数据结构类型转换为其他格式（字典、JSON、XML等），例如将Django中的模型类对象装换为JSON字符串，这个转换过程我们称为序列化。
简单的一句话理解就是将数据转化为JSON格式返回给前端

反序列化：
反之，将其他格式（字典、JSON、XML等）转换为程序中的数据，例如将JSON字符串转换为Django中的模型类对象，这个过程我们称为反序列化。

总结

在开发REST API时，视图中要频繁的进行序列化与反序列化的编写。

在开发REST API接口时，我们在视图中需要做的最核心的事是：

• 将数据库数据序列化为前端所需要的格式，并返回；
• 将前端发送的数据反序列化为模型类对象，并保存到数据库中。

二. 环境安装配置

1. 安装DRF

pip3 install -i https://pypi.tuna.tsinghua.edu.cn/simple  djangorestframework

2. 添加rest_framework应用

INSTALLED_APPS = [...'rest_framework',
]

接下来就可以使用DRF进行开发了。

普通的序列化器这里就不介绍了，下面介绍的时进阶版的模型类序列化器-ModelSerializer
此项目使用的时前后端不分离的开发模式，本质上给前端传递数据是一样的

三. 序列化与反序列化

模型表models.py

from django.contrib.auth.models import User
from django.db import modelsfrom apps.file.models import TeamDataStructureFile
from utils.base_models import BaseModelclass DataStructure(BaseModel):CATEGORY_CHOICES = [('Knowledge Category', 'Knowledge Category'),('Knowledge Category1', 'Knowledge Category1'),]TEAM_CHOICES = [('sys-tech', 'sys-tech'),('data structure', 'data structure'),]title = models.CharField(max_length=200, verbose_name='主题', blank=False)owner = models.CharField(max_length=50,blank=True,verbose_name='申请人ID')full_name = models.CharField(max_length=50,blank=False,verbose_name='申请人')knowledge_category = models.CharField(max_length=50,blank=False,choices=CATEGORY_CHOICES,verbose_name='知识类别')team = models.CharField(max_length=50,blank=False,choices=TEAM_CHOICES,verbose_name='团队')description = models.TextField(null=True, blank=True, verbose_name='描述')# 添加user, file复合主键# 一对多user = models.ForeignKey(User, null=True, blank=True, on_delete=models.SET_NULL)# 多对多attachments = models.ManyToManyField(TeamDataStructureFile, blank=True)class Meta:ordering = ['-create_time']def __str__(self):return self.title

序列化器serializers.py

from rest_framework.serializers import ModelSerializerfrom apps.file.models import TeamDataStructureFile
from apps.file.serializers import TeamDataStructureFileField
from teams.models import DataStructureclass DataStructureSerializer(ModelSerializer):"""序列化与反序列化数据时可以使用"""class Meta:model = DataStructurefields = '__all__'class EditDataStructureSerializer(ModelSerializer):"""编辑数据反序列化器"""class Meta:model = DataStructureexclude = ('attachments',)  # 若编辑文件接口提交时文件为空，此时不需要序列化此字段class TeamDataStructureQuerySerializer(ModelSerializer):"""查询所有数据的序列化器"""attachments = TeamDataStructureFileField(queryset=TeamDataStructureFile.objects.all(), many=True)class Meta:model = DataStructurefields = '__all__'

1.添加数据

视图函数views.py

class AddDataStructureView(LoginRequiredJSONMixin, APIView):def get(self, request):ds = DataStructure()knowledge_category = [i[1] for i in ds.CATEGORY_CHOICES]teams = [i[1] for i in ds.TEAM_CHOICES]context = {'add_knowledge_category': knowledge_category,'add_teams': teams,}return render(request, 'teams/data_structure/add_data_structure.html', context)@transaction.atomicdef post(self, request):"""反序列化一条数据，存入数据库"""# print(request.data)serializer = DataStructureSerializer(data=request.data)if serializer.is_valid():# serializer.ds = serializer.save()# handle filefiles_obj = request.FILES.getlist('uploadFile')if files_obj:handle_files(request, files_obj, ds, TeamFileSerializer)return api_success('信息保存成功！Data loading')return api_bad_request('表单数据输入有误,认证失败,数据无法保存!')

2.查询/编辑/删除数据

class DataStructureDetailView(LoginRequiredJSONMixin, APIView):def get(self, request, id):"""序列化器数据，并返回给前端"""ds = get_object_or_404(DataStructure, pk=id)s = DataStructureSerializer(ds)context = s.datacontext['teams'] = [i[1] for i in ds.TEAM_CHOICES if i[1] != s.data['team']]context['knowledge_categories'] = [i[1] for i in ds.CATEGORY_CHOICES if i[1] !=s.data['knowledge_category']]attachments = ds.attachments.all()initialPreviewData = []try:for file in attachments:initialPreviewData.append({'file_id': file.id,'file_url': SERVER_URL + '/' + file.file.url,'file_type': file.suffix.lower(),'file_name': file.filename,'file_size': file.file.size})except Exception as e:logger.info('get DataStructureDetailView error:{}'.format(e))context['initialPreviewData'] = initialPreviewDatacontext['user'] = ds.user# print(context)return render(request, 'teams/data_structure/edit_data_structure.html', context)@transaction.atomicdef put(self, request, id):""""反序列化数据，存入数据库"""# print(request.data)ds = get_object_or_404(DataStructure, pk=id)old_ds = copy.copy(ds)# 此处重新定义了序列化器是因为文件传过来的时候为空，所以需要重新定义新的序列化器，先处理数据，再处理文件，exclude attachments字段可使该字段在处理数据时被忽略，最后在单独处理该字段s = EditDataStructureSerializer(instance=ds, data=request.data)if s.is_valid():new_ds = s.save()# handle filefiles_obj = request.FILES.getlist('uploadFile')if files_obj:handle_files(request, files_obj, new_ds, TeamFileSerializer)# 变更差异信息# old_ds_dic = model_to_dict(old_ds)# new_ds_dic = model_to_dict(new_ds)# diff = old_ds_dic.keys() & new_ds_dic# diff_vals = [(k + ': from ' + str(old_ds_dic[k]) + ' to ' + str(new_ds_dic[k])) for k in diff if#              old_ds_dic[k] != new_ds_dic[k]]# print(diff_vals)return api_success('信息保存成功！Data loading')return api_bad_request('数据表单验证失败,无法保存！')def delete(self, request, id):# print(request, id)ds = get_object_or_404(DataStructure, pk=id)res = delete_data(ds)if res:return api_success(res)return api_bad_request('数据删除失败！')

封装的文件处理函数public.py，也是多对多外键attachments字段数据库处理的方式

def handle_files(request, files_obj, obj, FileSerializer):"""该函数传参对象有attachments属性时才可调用"""files = []for file_obj in files_obj:filename = file_obj.namesuffix = filename.rsplit(".", 1)[1]file_data = {'file': file_obj,'filename': filename,'suffix': suffix,}if request.method == 'PUT':# 1.本地文件删除obj_files = obj.attachments.all()for file in obj_files:file.file.delete()# 2.文件数据记录删除（先删除子表数据记录）obj_files.delete()fs = FileSerializer(data=file_data)if fs.is_valid():new_file = fs.save()new_file.content_object = objnew_file.save()files.append(fs.data.get('id'))if request.method == 'POST':obj.attachments.add(*files)if request.method == 'PUT':obj.attachments.set(files)def delete_data(obj):"""该函数传参对象有attachments属性时才可调用"""# 设置事务，保证数据的同步with transaction.atomic():save_point = transaction.savepoint()try:# 1.本地文件删除files = obj.attachments.all()if files:for file in files:file.file.delete()# 2.文件数据记录删除（先删除子表数据记录）files.delete()# 3.数据删除（再父表数据记录删除）obj.delete()except Exception as e:transaction.rollback(save_point)logger.info('obj->{} file delete error:{}'.format(obj, e))else:transaction.savepoint_commit(save_point)msg = '数据删除成功！Data loading......'return msgdef get_page_all_data(total, rows, sortOrder, pageNumber, pageSize):for i in range(len(rows)):if sortOrder == 'desc':no = total - (pageNumber - 1) * pageSize - ielse:no = (pageNumber - 1) * pageSize + i + 1rows[i]['no'] = nodata = {"total": total, "rows": rows}return data

3.分页查询数据处理

class DataStructureListView(APIView):def get(self, request):pageSize = int(request.GET.get('pageSize', 10))pageNumber = int(request.GET.get('pageNumber', 1))search_kw = request.GET.get('search_kw', '')sortName = request.GET.get('sortName', '')sortOrder = request.GET.get('sortOrder', '')ds_all = DataStructure.objects.all()# 查询if search_kw:ds_all = ds_all.filter(Q(title__icontains=search_kw) | Q(description__icontains=search_kw) | Q(full_name__icontains=search_kw))if sortName == 'no':sortName = 'id'# 排序if sortOrder == 'desc':ds_list = ds_all.order_by('-{}'.format(sortName))[(pageNumber - 1) * pageSize:(pageNumber) * pageSize]else:ds_list = ds_all.order_by(sortName)[(pageNumber - 1) * pageSize:(pageNumber) * pageSize]total = ds_all.count()# print(ds_list)# page_data = self.get_page_data(ds_list, total, sortOrder, pageNumber, pageSize)rows = TeamDataStructureQuerySerializer(ds_list, many=True).datapage_data = get_page_all_data(total, rows, sortOrder, pageNumber, pageSize)if page_data:return JsonResponse(page_data)return api_bad_request('数据加载失败！')def get_page_data(self, obj_list, total, sortOrder, pageNumber, pageSize):"""不使用序列化器，前端需要修改attachment字段获取方式"""ds_list_len = len(obj_list)rows = []data = {"total": total, "rows": rows}for i in range(ds_list_len):attachments = {}attachments['file_name'] = [i.filename for i in obj_list[i].attachments.all()]attachments['id'] = [i.id for i in obj_list[i].attachments.all()]if sortOrder == 'desc':no = total - (pageNumber - 1) * pageSize - ielse:no = (pageNumber - 1) * pageSize + i + 1row = {'id': obj_list[i].id,'no': no,'title': obj_list[i].title,'description': obj_list[i].description,'team': obj_list[i].team,'created_date': obj_list[i].created_date,'full_name': obj_list[i].full_name,'knowledge_category': obj_list[i].knowledge_category,'attachments': attachments,}rows.append(row)return data

下面附上前端分页的代码

{% extends "base.html" %} {% load static %}{% block main %}
Key Features
Add some introduction here!

{#                            #                                 alt="">#}
Highrise ParameterList
Common Platform ParameterList
Other Features
Data Structure List
 Add new data structure
Team Members
Add some introduction here!
Tian Xia
Manager,....
Yang Fang
Responsibility
Wang Xiaonan
Responsibility
Ding Chenchen
Responsibility

{% endblock %}{% block script %}
{% endblock %}

免声明：以上内容和代码仅供参考！