python 全栈开发，Day99(作业讲解,DRF版本,DRF分页,DRF序列化进阶)

昨日内容回顾

1. 为什么要做前后端分离？
    - 前后端交给不同的人来编写，职责划分明确。
    - API        (IOS,安卓,PC,微信小程序...)
    - vue.js等框架编写前端时，会比之前写jQuery更简单快捷。

2. 简述http协议？
    - 基于socket
    - 数据格式：
        "GET /index?name=123&age=19 http1.1
host:www.luffyciti.com
content-type:application/json...

"
        
        "POST /index http1.1
host:www.luffyciti.com
content-type:application/json...

{name:'alex',age:18}"
        
        "POST /index http1.1
host:www.luffyciti.com
content-type:application/enform.....

name=alex&age=18&xx=19"
   
    - 无状态短链接
        一次请求一次响应之后断开连接
        
3. 简述restful 规范？
    https://www.luffycity.com/api/v1/courses/?sub_category=0
    https://www.luffycity.com/api/v1/courses/?sub_category=0
    看上面一段url，可以说出5个
    1. 使用https代替http  2.在URL中体现自己写的是API 3. 在URL中体现版本  4. 使用名词 5.参数要合理
    之后，请求方式，响应信息。可以说后面5个
    6. 根据请求方式不同,处理不同的操作 7.返回状态码 8.返回错误信息 9. 返回code 10.hyper link(超链接)
    
4. django rest framework组件的作用？
    - 快速实现符合restful 规范的api
        
5. 列举django rest framework组件（10个）？
    - 版本
    - 权限
    - 认证
    - 节流
    - 分页
    - 解析器
    - 序列化
    - 视图
    - 路由 
    - 渲染器
    
6. 路飞的表结构
    a. 课程分类 
        - 课程大类
        - 课程子类 
    b. 学位课 
        - 学位课
        - 奖学金 
        - 老师 
    c. 专题课 or 学位课模块
        - 专题课 or 学位课模块
        - 课程详细 
        - 课程大纲
        - 常见问题 
        - 章节 
        - 课时
        - 作业 
    d. 价格
        - 价格策略

7. django contenttypes组件的作用？
    为了解决一张表和多个表做外键关联

View Code

上面都是面试题

列举django rest framework的10个组件，可以根据django请求生命周期来记

1. 请求路径包含版本，请求先到达路由，2.进入组件。认证，权限，节流。3.到达视图，获取参数，使用解析器。4.获取数据库记录,做序列化返回。
5.数据太多，要做分页，返回给用户之后，要做渲染，利用渲染器。

一、作业讲解

下面代码：
https://github.com/987334176/luffycity/archive/v1.zip

修改models.py

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.db.models import Q
from django.utils.safestring import mark_safe
from django.db import models
import hashlib


# ######################## 课程相关 ########################

class CourseCategory(models.Model):
    """课程大类, e.g 前端  后端..."""
    name = models.CharField(max_length=64, unique=True)

    def __str__(self):
        return "%s" % self.name

    class Meta:
        verbose_name_plural = "01.课程大类"


class CourseSubCategory(models.Model):
    """课程子类, e.g python linux """
    category = models.ForeignKey("CourseCategory")
    name = models.CharField(max_length=64, unique=True)

    def __str__(self):
        return "%s" % self.name

    class Meta:
        verbose_name_plural = "02.课程子类"


class DegreeCourse(models.Model):
    """学位课程"""
    name = models.CharField(max_length=128, unique=True)
    course_img = models.CharField(max_length=255, verbose_name="缩略图")
    brief = models.TextField(verbose_name="学位课程简介", )
    total_scholarship = models.PositiveIntegerField(verbose_name="总奖学金(贝里)", default=40000)  # 2000 2000
    mentor_compensation_bonus = models.PositiveIntegerField(verbose_name="本课程的导师辅导费用(贝里)", default=15000)
    period = models.PositiveIntegerField(verbose_name="建议学习周期(days)", default=150)  # 为了计算学位奖学金
    prerequisite = models.TextField(verbose_name="课程先修要求", max_length=1024)
    teachers = models.ManyToManyField("Teacher", verbose_name="课程讲师")

    # 用于GenericForeignKey反向查询， 不会生成表字段，切勿删除
    # coupon = GenericRelation("Coupon")

    # 用于GenericForeignKey反向查询，不会生成表字段，切勿删除
    degreecourse_price_policy = GenericRelation("PricePolicy")

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "03.学位课"


class Teacher(models.Model):
    """讲师、导师表"""
    name = models.CharField(max_length=32)
    role_choices = ((0, '讲师'), (1, '导师'))
    role = models.SmallIntegerField(choices=role_choices, default=0)
    title = models.CharField(max_length=64, verbose_name="职位、职称")
    signature = models.CharField(max_length=255, help_text="导师签名", blank=True, null=True)
    image = models.CharField(max_length=128)
    brief = models.TextField(max_length=1024)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "04.导师或讲师"


class Scholarship(models.Model):
    """学位课程奖学金"""
    degree_course = models.ForeignKey("DegreeCourse")
    time_percent = models.PositiveSmallIntegerField(verbose_name="奖励档位(时间百分比)", help_text="只填百分值，如80,代表80%")
    value = models.PositiveIntegerField(verbose_name="奖学金数额")

    def __str__(self):
        return "%s:%s" % (self.degree_course, self.value)

    class Meta:
        verbose_name_plural = "05.学位课奖学金"


class Course(models.Model):
    """专题课/学位课模块表"""
    name = models.CharField(max_length=128, unique=True)
    course_img = models.CharField(max_length=255)
    sub_category = models.ForeignKey("CourseSubCategory")
    course_type_choices = ((0, '付费'), (1, 'VIP专享'), (2, '学位课程'))
    course_type = models.SmallIntegerField(choices=course_type_choices)

    # 不为空；学位课的某个模块
    # 为空；专题课
    degree_course = models.ForeignKey("DegreeCourse", blank=True, null=True, help_text="若是学位课程，此处关联学位表")

    brief = models.TextField(verbose_name="课程概述", max_length=2048)
    level_choices = ((0, '初级'), (1, '中级'), (2, '高级'))
    level = models.SmallIntegerField(choices=level_choices, default=1)
    pub_date = models.DateField(verbose_name="发布日期", blank=True, null=True)
    period = models.PositiveIntegerField(verbose_name="建议学习周期(days)", default=7)  #
    order = models.IntegerField("课程顺序", help_text="从上一个课程数字往后排")
    attachment_path = models.CharField(max_length=128, verbose_name="课件路径", blank=True, null=True)
    status_choices = ((0, '上线'), (1, '下线'), (2, '预上线'))
    status = models.SmallIntegerField(choices=status_choices, default=0)
    template_id = models.SmallIntegerField("前端模板id", default=1)

    # coupon = GenericRelation("Coupon")

    # 用于GenericForeignKey反向查询，不会生成表字段，切勿删除
    price_policy = GenericRelation("PricePolicy")

    asked_question = GenericRelation("OftenAskedQuestion")


    def __str__(self):
        return "%s(%s)" % (self.name, self.get_course_type_display())


    def save(self, *args, **kwargs):
        if self.course_type == 2:
            if not self.degree_course:
                raise ValueError("学位课程必须关联对应的学位表")
        super(Course, self).save(*args, **kwargs)


    class Meta:
        verbose_name_plural = "06.专题课或学位课模块"


class CourseDetail(models.Model):
    """课程详情页内容"""
    course = models.OneToOneField("Course")
    hours = models.IntegerField("课时")
    course_slogan = models.CharField(max_length=125, blank=True, null=True)
    video_brief_link = models.CharField(verbose_name='课程介绍', max_length=255, blank=True, null=True)
    why_study = models.TextField(verbose_name="为什么学习这门课程")
    what_to_study_brief = models.TextField(verbose_name="我将学到哪些内容")
    career_improvement = models.TextField(verbose_name="此项目如何有助于我的职业生涯")
    prerequisite = models.TextField(verbose_name="课程先修要求", max_length=1024)
    recommend_courses = models.ManyToManyField("Course", related_name="recommend_by", blank=True)
    teachers = models.ManyToManyField("Teacher", verbose_name="课程讲师")

    def __str__(self):
        return "%s" % self.course

    class Meta:
        verbose_name_plural = "07.课程或学位模块详细"


class OftenAskedQuestion(models.Model):
    """常见问题"""
    content_type = models.ForeignKey(ContentType)  # 关联course or degree_course
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    question = models.CharField(max_length=255)
    answer = models.TextField(max_length=1024)


    def __str__(self):
        return "%s-%s" % (self.content_object, self.question)


    class Meta:
        unique_together = ('content_type', 'object_id', 'question')
        verbose_name_plural = "08. 常见问题"


class CourseOutline(models.Model):
    """课程大纲"""
    course_detail = models.ForeignKey("CourseDetail")
    title = models.CharField(max_length=128)
    # 前端显示顺序
    order = models.PositiveSmallIntegerField(default=1)

    content = models.TextField("内容", max_length=2048)

    def __str__(self):
        return "%s" % self.title

    class Meta:
        unique_together = ('course_detail', 'title')
        verbose_name_plural = "09. 课程大纲"


class CourseChapter(models.Model):
    """课程章节"""
    course = models.ForeignKey("Course")
    chapter = models.SmallIntegerField(verbose_name="第几章", default=1)
    name = models.CharField(max_length=128)
    summary = models.TextField(verbose_name="章节介绍", blank=True, null=True)
    pub_date = models.DateField(verbose_name="发布日期", auto_now_add=True)

    class Meta:
        unique_together = ("course", 'chapter')
        verbose_name_plural = "10. 课程章节"

    def __str__(self):
        return "%s:(第%s章)%s" % (self.course, self.chapter, self.name)


class CourseSection(models.Model):
    """课时目录"""
    chapter = models.ForeignKey("CourseChapter")
    name = models.CharField(max_length=128)
    order = models.PositiveSmallIntegerField(verbose_name="课时排序", help_text="建议每个课时之间空1至2个值，以备后续插入课时")
    section_type_choices = ((0, '文档'), (1, '练习'), (2, '视频'))
    section_type = models.SmallIntegerField(default=2, choices=section_type_choices)
    section_link = models.CharField(max_length=255, blank=True, null=True, help_text="若是video，填vid,若是文档，填link")
    video_time = models.CharField(verbose_name="视频时长", blank=True, null=True, max_length=32)  # 仅在前端展示使用
    pub_date = models.DateTimeField(verbose_name="发布时间", auto_now_add=True)
    free_trail = models.BooleanField("是否可试看", default=False)

    class Meta:
        unique_together = ('chapter', 'section_link')
        verbose_name_plural = "11. 课时"

    def __str__(self):
        return "%s-%s" % (self.chapter, self.name)


class Homework(models.Model):
    chapter = models.ForeignKey("CourseChapter")
    title = models.CharField(max_length=128, verbose_name="作业题目")
    order = models.PositiveSmallIntegerField("作业顺序", help_text="同一课程的每个作业之前的order值间隔1-2个数")
    homework_type_choices = ((0, '作业'), (1, '模块通关考核'))
    homework_type = models.SmallIntegerField(choices=homework_type_choices, default=0)
    requirement = models.TextField(max_length=1024, verbose_name="作业需求")
    threshold = models.TextField(max_length=1024, verbose_name="踩分点")
    recommend_period = models.PositiveSmallIntegerField("推荐完成周期(天)", default=7)
    scholarship_value = models.PositiveSmallIntegerField("为该作业分配的奖学金(贝里)")
    note = models.TextField(blank=True, null=True)
    enabled = models.BooleanField(default=True, help_text="本作业如果后期不需要了，不想让学员看到，可以设置为False")

    class Meta:
        unique_together = ("chapter", "title")
        verbose_name_plural = "12. 章节作业"

    def __str__(self):
        return "%s - %s" % (self.chapter, self.title)


# class CourseReview(models.Model):
#     """课程评价"""
#     enrolled_course = models.OneToOneField("EnrolledCourse")
#     about_teacher = models.FloatField(default=0, verbose_name="讲师讲解是否清晰")
#     about_video = models.FloatField(default=0, verbose_name="内容实用")
#     about_course = models.FloatField(default=0, verbose_name="课程内容通俗易懂")
#     review = models.TextField(max_length=1024, verbose_name="评价")
#     disagree_number = models.IntegerField(default=0, verbose_name="踩")
#     agree_number = models.IntegerField(default=0, verbose_name="赞同数")
#     tags = models.ManyToManyField("Tags", blank=True, verbose_name="标签")
#     date = models.DateTimeField(auto_now_add=True, verbose_name="评价日期")
#     is_recommend = models.BooleanField("热评推荐", default=False)
#     hide = models.BooleanField("不在前端页面显示此条评价", default=False)
#
#     def __str__(self):
#         return "%s-%s" % (self.enrolled_course.course, self.review)
#
#     class Meta:
#         verbose_name_plural = "13. 课程评价（购买课程后才能评价）"
#
#
# class DegreeCourseReview(models.Model):
#     """学位课程评价
#     为了以后可以定制单独的评价内容，所以不与普通课程的评价混在一起，单独建表
#     """
#     enrolled_course = models.ForeignKey("EnrolledDegreeCourse")
#     course = models.ForeignKey("Course", verbose_name="评价学位模块", blank=True, null=True,
#                                help_text="不填写即代表评价整个学位课程", limit_choices_to={'course_type': 2})
#     about_teacher = models.FloatField(default=0, verbose_name="讲师讲解是否清晰")
#     about_video = models.FloatField(default=0, verbose_name="视频质量")
#     about_course = models.FloatField(default=0, verbose_name="课程")
#     review = models.TextField(max_length=1024, verbose_name="评价")
#     disagree_number = models.IntegerField(default=0, verbose_name="踩")
#     agree_number = models.IntegerField(default=0, verbose_name="赞同数")
#     tags = models.ManyToManyField("Tags", blank=True, verbose_name="标签")
#     date = models.DateTimeField(auto_now_add=True, verbose_name="评价日期")
#     is_recommend = models.BooleanField("热评推荐", default=False)
#     hide = models.BooleanField("不在前端页面显示此条评价", default=False)
#
#     def __str__(self):
#         return "%s-%s" % (self.enrolled_course, self.review)
#
#     class Meta:
#         verbose_name_plural = "14. 学位课评价（购买课程后才能评价）"


class PricePolicy(models.Model):
    """价格与有课程效期表"""
    content_type = models.ForeignKey(ContentType)  # 关联course or degree_course
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    # course = models.ForeignKey("Course")
    valid_period_choices = ((1, '1天'), (3, '3天'),
                            (7, '1周'), (14, '2周'),
                            (30, '1个月'),
                            (60, '2个月'),
                            (90, '3个月'),
                            (180, '6个月'), (210, '12个月'),
                            (540, '18个月'), (720, '24个月'),
                            )
    valid_period = models.SmallIntegerField(choices=valid_period_choices)
    price = models.FloatField()

    class Meta:
        unique_together = ("content_type", 'object_id', "valid_period")
        verbose_name_plural = "15. 价格策略"

    def __str__(self):
        return "%s(%s)%s" % (self.content_object, self.get_valid_period_display(), self.price)

View Code

下载数据库使用(务必下载，上面的压缩包数据库是空的！！！)

https://github.com/987334176/luffycity/blob/master/db.sqlite3

修改api应用下的api_urls.py

from django.conf.urls import url
from api import views

urlpatterns = [
    url(r'index/$', views.CheckView.as_view()),
]

View Code

a

查看所有学位课并打印学位课名称以及授课老师

修改api应用下的views.py

from django.shortcuts import render,HttpResponse
from api import models
from django.views import View

# Create your views here.
class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # a.查看所有学位课并打印学位课名称以及授课老师
        degree_list = models.DegreeCourse.objects.all().values('name', 'teachers__name')
        print(degree_list)
        return HttpResponse('ok')

View Code

访问网页：http://127.0.0.1:8000/api/index/

查看控制台输出：

<QuerySet [{'teachers__name': '李泳谊', 'name': 'Linux自动化运维 · 中级'}, {'teachers__name': 'Alex 金角大王', 'name': 'Python全栈开发 · 中级'}]>

第二种写法：

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # a.查看所有学位课并打印学位课名称以及授课老师
        queryset = models.DegreeCourse.objects.all()
        for row in queryset:
            print(row.name,row.teachers.all())
            
        return HttpResponse('ok')

View Code

查看控制台输出：

<QuerySet [{'teachers__name': '李泳谊', 'name': 'Linux自动化运维 · 中级'}, {'teachers__name': 'Alex 金角大王', 'name': 'Python全栈开发 · 中级'}]>

b

查看所有学位课并打印学位课名称以及学位课的奖学金

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # b.查看所有学位课并打印学位课名称以及学位课的奖学金
        c_obj=models.DegreeCourse.objects.all()
        for i in c_obj:
            # 利用degreecourse_price_policy字段进行反向查询
            print(i.name,i.degreecourse_price_policy.all().values('price'))

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

Python全栈开发 · 中级 <QuerySet [{'price': 10.0}]>
Linux自动化运维 · 中级 <QuerySet [{'price': 50.0}]>

第二种写法：

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # b.查看所有学位课并打印学位课名称以及学位课的奖学金
        degree_list = models.DegreeCourse.objects.all()
        for row in degree_list:
            print(row.name)
            scholarships = row.scholarship_set.all()
            for item in scholarships:
                print('------>',item.time_percent,item.value)

View Code

执行输出：

Python全栈开发 · 中级
------> 50 1000
Linux自动化运维 · 中级
------> 50 1000

c

展示所有的专题课

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # c. 展示所有的专题课
        c_obj = models.Course.objects.filter(degree_course__isnull=True)
        print(c_obj)

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

<QuerySet [<Course: Linux基础(付费)>]>

d

查看id=1的学位课对应的所有模块名称

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # d. 查看id=1的学位课对应的所有模块名称
        obj = models.DegreeCourse.objects.filter(id=1).values('course__name')
        print(obj)

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

<QuerySet [<Course: Linux基础(付费)>]>

e

获取id = 1的专题课，并打印：课程名、级别(中文)、why_study、what_to_study_brief、所有recommend_courses

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # e. 获取id = 1的专题课，并打印：课程名、级别(中文)、why_study、what_to_study_brief、所有recommend_courses
        c_obj = models.Course.objects.filter(id=1)
        print(c_obj.values('name'))
        print(c_obj.first().get_level_display())
        print(c_obj.values('coursedetail__why_study'))
        print(c_obj.values('coursedetail__what_to_study_brief'))
        print(c_obj.values('coursedetail__recommend_courses'))

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

<QuerySet [{'name': 'Python开发入门7天特训营'}]>
初级
<QuerySet [{'coursedetail__why_study': '适合零基础学编程的小白，语言简洁高效，为进入人工智能、数据分析和网站开发做好准备；如果你准备敲下你人生的第一行代码、写出你的第一个程序，路飞学城的入门特训营会是最好的选择'}]>
<QuerySet [{'coursedetail__what_to_study_brief': '1、Python如何才能掌握真正的要领；
2、看完理论课程自己怎么开始动手写出代码；
3、什么才是专业的代码；
4、最流行Python编程工具使用技巧；
5、如何系统且高效的学习Python，遇到问题该如何入手分析
6、可以自主开发各种小程序（如分数打印、猜年龄、用户登录程序、三级菜单等）'}]>
<QuerySet [{'coursedetail__recommend_courses': 1}]>

View Code

第二种写法：

Python开发入门7天特训营
适合零基础学编程的小白，语言简洁高效，为进入人工智能、数据分析和网站开发做好准备；如果你准备敲下你人生的第一行代码、写出你的第一个程序，路飞学城的入门特训营会是最好的选择
初级
7
适合零基础学编程的小白，语言简洁高效，为进入人工智能、数据分析和网站开发做好准备；如果你准备敲下你人生的第一行代码、写出你的第一个程序，路飞学城的入门特训营会是最好的选择
<QuerySet [<Course: Python开发入门7天特训营(付费)>]>

View Code

刷新网页，查看控制台输出：

Python开发入门7天特训营
适合零基础学编程的小白，语言简洁高效，为进入人工智能、数据分析和网站开发做好准备；如果你准备敲下你人生的第一行代码、写出你的第一个程序，路飞学城的入门特训营会是最好的选择
初级
7
适合零基础学编程的小白，语言简洁高效，为进入人工智能、数据分析和网站开发做好准备；如果你准备敲下你人生的第一行代码、写出你的第一个程序，路飞学城的入门特训营会是最好的选择
<QuerySet [<Course: Python开发入门7天特训营(付费)>]>

View Code

注意：显示choices的中文，使用get_字段名_display() 就可以了！

f

获取id = 1的专题课，并打印该课程相关的所有常见问题

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # f. 获取id = 1的专题课，并打印该课程相关的所有常见问题
        c_obj = models.Course.objects.filter(id=1).first()
        # 利用asked_question字段进行反向查询
        print(c_obj.asked_question.all().values('question'))

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

<QuerySet [{'question': '我是零基础，能学会吗？'}, {'question': '需要学习多长时间？'}]>

第二种写法：

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # f. 获取id = 1的专题课，并打印该课程相关的所有常见问题
        obj = models.Course.objects.get(id=1)
        ask_list = obj.asked_question.all()
        for item in ask_list:
            print(item.question)

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

我是零基础，能学会吗？
需要学习多长时间？

g

获取id = 1的专题课，并打印该课程相关的课程大纲

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # g.获取id = 1的专题课，并打印该课程相关的课程大纲
        c_obj = models.Course.objects.filter(id=1)
        print(c_obj.values('coursedetail__courseoutline__title'))

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

<QuerySet [{'coursedetail__courseoutline__title': 'Python基础知识'}, {'coursedetail__courseoutline__title': 'Python数据类型初识'}]>

第二种写法：

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # g.获取id = 1的专题课，并打印该课程相关的课程大纲
        obj = models.Course.objects.get(id=1)
        outline_list = obj.coursedetail.courseoutline_set.all()
        for item in outline_list:
            print(item.title,item.content)

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

Python基础知识 Python基础知识、开营直播课
Python数据类型初识 Python数据类型初识、流程控制

h

获取id = 1的专题课，并打印该课程相关的所有章节

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # h.获取id = 1的专题课，并打印该课程相关的所有章节
        c_obj = models.Course.objects.filter(id=1)
        print(c_obj.values('coursechapter__name'))

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

<QuerySet [{'coursechapter__name': 'Python基础知识'}, {'coursechapter__name': 'Python数据类型初识'}]>

第二种写法，使用反向查询

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # h.获取id = 1的专题课，并打印该课程相关的所有章节
        obj = models.Course.objects.get(id=1)
        chapter_list = obj.coursechapter_set.all() # 默认obj.表名_set.all()
        for item in chapter_list:
            print(item.name)

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

Python基础知识
Python数据类型初识

i

获取id = 1的专题课，并打印该课程相关的所有课时

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # i.获取id = 1的专题课，并打印该课程相关的所有课时
        c_obj = models.Course.objects.filter(id=1)
        for i in c_obj.values('coursechapter__chapter','coursechapter__name'):
            print(i.get('coursechapter__chapter'),i.get('coursechapter__name'))
            a_obj=models.CourseChapter.objects.filter(name=i.get('coursechapter__name'))
            for j in a_obj.values('coursesection__name'):
                print('  ',j.get('coursesection__name'))

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

1 Python基础知识
   python基础
2 Python数据类型初识
   数据类型

第二种写法：

class CheckView(View):
    """
    练习题相关
    """
    def get(self, request):
        # i.获取id = 1的专题课，并打印该课程相关的所有课时
        obj = models.Course.objects.get(id=1)
        chapter_list = obj.coursechapter_set.all()
        for chapter in chapter_list:
            print(chapter.name,chapter.coursesection_set.all())

        return HttpResponse('ok')

View Code

刷新网页，查看控制台输出：

Python数据类型初识 <QuerySet [<CourseSection: Python开发入门7天特训营(付费):(第2章)Python数据类型初识-数据类型>]>

所有视图都集中在views.py中，扩展不方便。

删除views.py，并创建目录views

在views目录里面创建course.py，它表示和课程相关的视图

注意：视图名最好加上View，这是约定俗成的

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView

class CourseView(APIView):
    def get(self,request,*args,**kwargs):
        return HttpResponse('ok')

View Code

修改api_urls.py

from django.conf.urls import url
from api.views import course

urlpatterns = [
    url(r'course/$', course.CourseView.as_view()),
]

View Code

访问网页：http://127.0.0.1:8000/api/course/

二、DRF版本

在Django rest-framework中提供了5中version设置方式

基于url的get传参方式

比如：/course?version=v1

settings.py，最后一行添加。这里面规定了版本为v1和v2，如果是其他版本，会报404错误！

REST_FRAMEWORK = {
    'DEFAULT_VERSION': 'v1',            # 默认版本
    'ALLOWED_VERSIONS': ['v1', 'v2'],   # 允许的版本
    'VERSION_PARAM': 'version'          # URL中获取值的key
}

View Code

api_urls.py

from django.conf.urls import url
from api.views import course

urlpatterns = [
    url(r'course/$', course.CourseView.as_view(),name='test'),
]

View Code

course.py

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.versioning import QueryParameterVersioning
from rest_framework.response import Response

class CourseView(APIView):
    # 开启版本支持功能
    versioning_class = QueryParameterVersioning

    def get(self, request, *args, **kwargs):
        # 获取版本
        print(request.version)
        # 获取版本管理的类
        print(request.versioning_scheme)

        # 反向生成URL
        reverse_url = request.versioning_scheme.reverse('test', request=request)
        print(reverse_url)

        return Response('GET请求，响应内容')

View Code

访问网页： http://127.0.0.1:8000/api/course/

查看Pycharm控制台输出：

v1
<rest_framework.versioning.QueryParameterVersioning object at 0x000001AAE5245F28>
http://127.0.0.1:8000/api/course/?version=v1

基于url的正则方式(推荐)

比如：/v1/users/

settings.py，保持不变

api_urls.py

from django.conf.urls import url
from api.views import course

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/course/$', course.CourseView.as_view(), name='test'),
]

View Code

course.py，修改versioning_class

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.versioning import URLPathVersioning
from rest_framework.response import Response

class CourseView(APIView):
    # 开启版本支持功能
    versioning_class = URLPathVersioning

    def get(self, request, *args, **kwargs):
        # 获取版本
        print(request.version)
        # 获取版本管理的类
        print(request.versioning_scheme)

        # 反向生成URL
        reverse_url = request.versioning_scheme.reverse('test', request=request)
        print(reverse_url)

        return Response('GET请求，响应内容')

View Code

访问网页： http://127.0.0.1:8000/api/v1/course/

注意要带版本，否则报错

查看Pycharm控制台输出：

v1
<rest_framework.versioning.URLPathVersioning object at 0x00000200F0F2E4A8>
http://127.0.0.1:8000/api/v1/course/

基于 accept 请求头方式

比如：Accept: application/json; version=1.0

老外喜欢用这种方法，因为比较安全

settings.py，保持不变

api_urls.py

from django.conf.urls import url
from api.views import course

urlpatterns = [
    url(r'^course/$', course.CourseView.as_view(), name='test'),
]

View Code

course.py，修改versioning_class

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.versioning import AcceptHeaderVersioning
from rest_framework.response import Response

class CourseView(APIView):
    # 开启版本支持功能
    versioning_class = AcceptHeaderVersioning

    def get(self, request, *args, **kwargs):
        # 获取版本 HTTP_ACCEPT头
        print(request.version)
        # 获取版本管理的类
        print(request.versioning_scheme)
        # 反向生成URL
        reverse_url = request.versioning_scheme.reverse('test', request=request)
        print(reverse_url)

        return Response('GET请求，响应内容')

View Code

使用postman发送get请求，增加一个头version

查看Pycharm控制台输出：

v1
<rest_framework.versioning.AcceptHeaderVersioning object at 0x000001AEA89206D8>
http://127.0.0.1:8000/api/course/

基于主机名方式

比如：v1.example.com

settings.py，允许所有主机访问

ALLOWED_HOSTS = ['*']

api_urls.py，保持不变

course.py，修改versioning_class

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.versioning import HostNameVersioning
from rest_framework.response import Response

class CourseView(APIView):
    # 开启版本支持功能
    versioning_class = HostNameVersioning

    def get(self, request, *args, **kwargs):
        # 获取版本
        print(request.version)
        # 获取版本管理的类
        print(request.versioning_scheme)

        # 反向生成URL
        reverse_url = request.versioning_scheme.reverse('test', request=request)
        print(reverse_url)

        return Response('GET请求，响应内容')

View Code

修改本机的hosts文件，增加2条记录

127.0.0.1    v1.example.com
127.0.0.1    v2.example.com

访问url: http://v1.example.com:8000/api/course/

查看Pycharm控制台输出：

v1
<rest_framework.versioning.HostNameVersioning object at 0x000001DE71A00470>
http://127.0.0.1:8000/api/course/

访问url： http://v2.example.com:8000/api/course/

查看Pycharm控制台输出：

v2
<rest_framework.versioning.HostNameVersioning object at 0x000001B31D5C3E48>
http://v2.example.com:8000/api/course/

基于django路由系统的namespace

比如：example.com/v1/users/

settings.py，保持不变

api_urls.py

from django.conf.urls import url
from api.views import course

urlpatterns = [
    url(r'^v1/', ([url(r'course/', course.CourseView.as_view(), name='test'), ], None, 'v1')),
    url(r'^v2/', ([url(r'course/', course.CourseView.as_view(), name='test'), ], None, 'v2')),
]

View Code

course.py

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.versioning import NamespaceVersioning
from rest_framework.response import Response

class CourseView(APIView):
    # 开启版本支持功能
    versioning_class = NamespaceVersioning

    def get(self, request, *args, **kwargs):
        # 获取版本
        print(request.version)
        # 获取版本管理的类
        print(request.versioning_scheme)

        # 反向生成URL
        reverse_url = request.versioning_scheme.reverse('test', request=request)
        print(reverse_url)

        return Response('GET请求，响应内容')

View Code

访问url: http://127.0.0.1:8000/api/v1/course/

查看Pycharm控制台输出：

v1
<rest_framework.versioning.NamespaceVersioning object at 0x0000020BC5FAFDA0>
http://127.0.0.1:8000/api/v1/course/

全局使用方式

settings.py

REST_FRAMEWORK = {
    'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.URLPathVersioning",
    'DEFAULT_VERSION': 'v1',
    'ALLOWED_VERSIONS': ['v1', 'v2'],
    'VERSION_PARAM': 'version' 
}

View Code

api_urls.py

from django.conf.urls import url
from api.views import course

urlpatterns = [
    url(r'^course/', course.CourseView.as_view(), name='test'),
]

View Code

course.py

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
# from rest_framework.versioning import NamespaceVersioning
from rest_framework.response import Response

class CourseView(APIView):
    # 开启版本支持功能
    # versioning_class = NamespaceVersioning

    def get(self, request, *args, **kwargs):
        # 获取版本
        print(request.version)
        # 获取版本管理的类
        print(request.versioning_scheme)

        # # 反向生成URL
        # reverse_url = request.versioning_scheme.reverse('test', request=request)
        # print(reverse_url)

        return Response('GET请求，响应内容')

View Code

访问url: http://127.0.0.1:8000/api/course/

查看Pycharm控制台输出：

v1
<rest_framework.versioning.URLPathVersioning object at 0x000001FF069907F0>

默认版本为v1

源码分析，请参考链接：

http://www.cnblogs.com/derek1184405959/p/8724270.html

总结：在认证，权限，节流之前做了版本处理

API编写

先做专题课

第一版，json

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
import json

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        """
        获取所有专题课信息
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        # 方式一：
        course_list = list(models.Course.objects.all().values('id','name'))
        return HttpResponse(json.dumps(course_list,ensure_ascii=False))

View Code

访问页面： http://127.0.0.1:8000/api/course/

第二版，序列化组件

在api应用目录下创建serializers文件夹，在里面创建course.py

from rest_framework import serializers


class CourseSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    name = serializers.CharField()

View Code

修改views目录下的course.py

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
from api.serializers.course import CourseSerializer

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        """
        获取所有专题课信息
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        # 方式二：
        course_list = models.Course.objects.all()
        ser = CourseSerializer(instance=course_list,many=True)
        return Response(ser.data)

View Code

刷新页面，效果如下：

三、DRF分页

如果当数据量特别大的时候，需要使用分页
REST框架支持自定义分页风格，如果使用的是APIView,你就需要自己调用分页API，确保返回一个分页后的响应。

指定每页大小

修改views目录下course.py

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
from api.serializers.course import CourseSerializer
from rest_framework.pagination import PageNumberPagination

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        # 从数据库中获取数据
        queryset = models.Course.objects.all()

        # 分页
        page = PageNumberPagination()
        # paginate_queryset 接收3参数,分别是queryset对象,request,视图
        # 这里的self就是CourseView视图
        course_list = page.paginate_queryset(queryset,request,self)
        # 分页之后的结果执行序列化
        ser = CourseSerializer(instance=course_list,many=True)
        return Response(ser.data)

View Code

修改settings.py，指定每页大小。这里表示每页一条数据

REST_FRAMEWORK = {
    'DEFAULT_VERSIONING_CLASS':"rest_framework.versioning.URLPathVersioning",
    'DEFAULT_VERSION': 'v1',
    'ALLOWED_VERSIONS': ['v1', 'v2'],
    'VERSION_PARAM': 'version',
    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
    'PAGE_SIZE':1
}

View Code

访问网页： http://127.0.0.1:8000/api/course/

效果如下：

获取下一页

怎么获取下一页呢？在url上面加一个参数page=页码数，比如：

http://127.0.0.1:8000/api/course/?page=2

效果如下

为什么参数是page呢？而不是其他的呢？看下面的源码

class PageNumberPagination(BasePagination):
    """
    A simple page number based style that supports page numbers as
    query parameters. For example:

    http://api.example.org/accounts/?page=4
    http://api.example.org/accounts/?page=4&page_size=100
    """
    # The default page size.
    # Defaults to `None`, meaning pagination is disabled.
    page_size = api_settings.PAGE_SIZE

    django_paginator_class = DjangoPaginator

    # Client can control the page using this query parameter.
    page_query_param = 'page'
    page_query_description = _('A page number within the paginated result set.')

    # Client can control the page size using this query parameter.
    # Default is 'None'. Set to eg 'page_size' to enable usage.
    page_size_query_param = None
    page_size_query_description = _('Number of results to return per page.')

    # Set to an integer to limit the maximum page size the client may request.
    # Only relevant if 'page_size_query_param' has also been set.
    max_page_size = None

    last_page_strings = ('last',)

    template = 'rest_framework/pagination/numbers.html'

    invalid_page_message = _('Invalid page.')

View Code

看这一行

page_query_param = 'page'

它指定了url参数为page

返回code

这里有一个问题，如果连接不上数据，就会报错
所以需要使用异常判断，定义一个字典，返回code

1000表示成功，500表示错误。备注：这个是自己定义的，看你的心情了！

修改views下的course.py

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
from api.serializers.course import CourseSerializer
from rest_framework.pagination import PageNumberPagination

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        response = {'code':1000,'data':None,'error':None}
        try:
            # 从数据库中获取数据
            queryset = models.Course.objects.all()

            # 分页
            page = PageNumberPagination()
            # paginate_queryset 接收3参数,分别是queryset对象,request,视图
            # 这里的self就是CourseView视图
            course_list = page.paginate_queryset(queryset,request,self)
            # 分页之后的结果执行序列化
            ser = CourseSerializer(instance=course_list,many=True)
            response['data'] = ser.data
        except Exception as e:
            response['code'] = 500
            response['error'] = '获取数据失败'

        return Response(response)

View Code

访问页面，发现数据多了几个key

模拟出错

修改views下的course.py，将ORM语句故意改错

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
from api.serializers.course import CourseSerializer
from rest_framework.pagination import PageNumberPagination

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        response = {'code':1000,'data':None,'error':None}
        try:
            # 从数据库中获取数据
            queryset = models.Course.objects.allxx()  # 模拟错误

            # 分页
            page = PageNumberPagination()
            # paginate_queryset 接收3参数,分别是queryset对象,request,视图
            # 这里的self就是CourseView视图
            course_list = page.paginate_queryset(queryset,request,self)
            # 分页之后的结果执行序列化
            ser = CourseSerializer(instance=course_list,many=True)
            response['data'] = ser.data
        except Exception as e:
            response['code'] = 500
            response['error'] = '获取数据失败'

        return Response(response)

View Code

刷新页面，提示失败

注意：每一个接口，一定要加try，防止程序崩溃

在公司里面写代码，必须这样。因为线上环境比较复杂，有各自攻击行为存在。所以，必须写异常判断。

而且，需要将异常信息写入日志。方便后续的排错，因为线上的代码，不能直接print，影响业务！

定义code类

这个视图定义了一个字典，用来做初始状态返回。那么其他视图，也需要返回code，再定义一遍？

如果有100个呢？所以，需要为这个功能，单独定义一个类。

这种是通用类，我们一般会放在应用(这里指的是api)下的utils(工具)文件夹中。

在api目录下创建utils文件夹，新建文件response.py

class BaseResponse(object):

    def __init__(self):
        self.code = 1000
        self.data = None
        self.error = None

    @property  # 负责把一个方法变成属性调用
    def dict(self):
        return self.__dict__

View Code

python中的类，都会从object里继承一个__dict__属性，这个属性中存放着类的属性和方法对应的键值对

修改views下的course.py，导入response

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
from api.serializers.course import CourseSerializer
from rest_framework.pagination import PageNumberPagination
from api.utils.response import BaseResponse

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        # response = {'code':1000,'data':None,'error':None}
        ret = BaseResponse()
        try:
            # 从数据库中获取数据
            queryset = models.Course.objects.all()

            # 分页
            page = PageNumberPagination()
            # paginate_queryset 接收3参数,分别是queryset对象,request,视图
            # 这里的self就是CourseView视图
            course_list = page.paginate_queryset(queryset,request,self)
            # 分页之后的结果执行序列化
            ser = CourseSerializer(instance=course_list,many=True)
            ret.data = ser.data
        except Exception as e:
            ret.code = 500
            ret.error = '获取数据失败'

        return Response(ret.__dict__)

View Code

刷新页面，效果如下：

第二版，到这里，就结束了。推荐使用第二种！

四、DRF序列化进阶

ModelSerializer

通常你会想要与Django模型相对应的序列化类。

ModelSerializer类能够让你自动创建一个具有模型中相应字段的Serializer类。

这个ModelSerializer类和常规的Serializer类一样，不同的是：

它根据模型自动生成一组字段。
它自动生成序列化器的验证器，比如unique_together验证器。
它默认简单实现了.create()方法和.update()方法。

查看serializers目录下course.py，这里我是手动指定了要序列化的字段，比如id和name

但是，还有更方便的方法。使用ModelSerializer，它会自动和ORM表关联。

修改serializers目录下course.py

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # id = serializers.IntegerField()
    # name = serializers.CharField()

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name']  # 指定序列化的字段

View Code

默认情况下，所有的模型的字段都将映射到序列化器上相应的字段。

模型中任何关联字段比如外键都将映射到PrimaryKeyRelatedField字段。默认情况下不包括反向关联，除非像serializer relations文档中规定的那样显示包含。

刷新页面，效果同上！

Model.get_FOO_display

查看官方文档

https://docs.djangoproject.com/en/dev/ref/models/instances/#django.db.models.Model.get_FOO_display

对于具有选择集的每个字段，该对象将具有一个get_FOO_display（）方法，其中FOO是该字段的名称。此方法返回字段的“可读”值。

查看models.py里面的Course类，看下面这2行

level_choices = ((0, '初级'), (1, '中级'), (2, '高级'))
level = models.SmallIntegerField(choices=level_choices, default=1)

level_choices 它只是一个变量而已，上面2行，可以合并为一行

level = models.SmallIntegerField(choices=((0, '初级'), (1, '中级'), (2, '高级')), default=1)

真正在数据库中，生成字段的是level。choices=xxx，表示它是一个选择集。真正在数据库存储的是1，后面的中文，主要是在前端展示的。这样做的目的，是为了节省磁盘空间。一般数据库用utf-8，一个中文占用3字节。而数字只占用1字节！

那么前端如何显示中文呢？使用get_level_display() ，注意：level是数据库的字段，值的类型必须是choices

修改serializers目录下course.py

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn']  # 指定序列化的字段

View Code

注意：level_cn只是一个变量名而已，约定俗成会定义为字段名。这里的get_level_display不需要加括号，它会自动执行！

刷新页面，效果如下：

一对一

Course和CourseDetail是一对一关系

现在需要显示课时，但是课时在另外一个表(CourseDetail课程详情表)中，可以用双下方法吗？

fields = ['id','name','level_cn','coursedetail__hours']

刷新页面，会报错

针对一对一的跨表查询，可以使用表名小写.字段名

修改serializers目录下course.py

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours']  # 指定序列化的字段

View Code

重启django项目，刷新页面

在Pycharm控制台，会有一个警告信息

UnorderedObjectListWarning: Pagination may yield inconsistent results with an unordered object_list:

百度翻译一下：

unOrdEdObjistList警告：分页可能与无序的对象列表产生不一致的结果：

啥意思呢？大概意思就是分页时，没有给它指定排序规则

修改views下的course.py，增加一个order_by就可以了

order_by('pk')，表示以主键排序，默认是升序

from django.shortcuts import render,HttpResponse
from api import models
from rest_framework.views import APIView
from rest_framework.response import Response
from api.serializers.course import CourseSerializer
from rest_framework.pagination import PageNumberPagination
from api.utils.response import BaseResponse

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        # response = {'code':1000,'data':None,'error':None}
        ret = BaseResponse()
        try:
            # 从数据库中获取数据
            queryset = models.Course.objects.all().order_by('pk')

            # 分页
            page = PageNumberPagination()
            # paginate_queryset 接收3参数,分别是queryset对象,request,视图
            # 这里的self就是CourseView视图
            course_list = page.paginate_queryset(queryset,request,self)
            # 分页之后的结果执行序列化
            ser = CourseSerializer(instance=course_list,many=True)
            ret.data = ser.data
        except Exception as e:
            ret.code = 500
            ret.error = '获取数据失败'

        return Response(ret.__dict__)

View Code

重启django项目，刷新页面。再次查看Pycharm控制台，就没有警告了！

多对多

CourseDetail表的recommend_courses字段和Course表，是多对多的关系

如果要显示recommend_courses(推荐课程)呢？可以使用表名小写.字段名吗？测试一下

修改serializers目录下course.py

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')
    recommend_courses = serializers.CharField(source='coursedetail.recommend_courses')

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours','recommend_courses']  # 指定序列化的字段

View Code

刷新页面，效果如下：

发现recommend_courses字段，并不是我们想要的结果

再加一个.all

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')
    recommend_courses = serializers.CharField(source='coursedetail.recommend_courses.all')

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours','recommend_courses']  # 指定序列化的字段

View Code

刷新页面，效果如下：

发现它是一个queryset对象，如何获取对象里面的属性呢？

get_{field_name}

它是用来获取别的表字段的。

查看serializers目录下course.py，点击CharField。搜索关键字get_{field_name}，看源码

    def bind(self, field_name, parent):
        # In order to enforce a consistent style, we error if a redundant
        # 'method_name' argument has been used. For example:
        # my_field = serializer.SerializerMethodField(method_name='get_my_field')
        default_method_name = 'get_{field_name}'.format(field_name=field_name)
        assert self.method_name != default_method_name, (
            "It is redundant to specify `%s` on SerializerMethodField '%s' in "
            "serializer '%s', because it is the same as the default method name. "
            "Remove the `method_name` argument." %
            (self.method_name, field_name, parent.__class__.__name__)
        )

        # The method name should default to `get_{field_name}`.
        if self.method_name is None:
            self.method_name = default_method_name

        super(SerializerMethodField, self).bind(field_name, parent)

View Code

修改serializers目录下course.py，专门定义一个方法，用来获取recommend_courses

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')
    # 显示推荐课程,对于多对多,使用def_字段名
    # SerializerMethodField表示序列化字段,使用方法获取
    recommend_courses = serializers.SerializerMethodField()

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours','recommend_courses']  # 指定序列化的字段

    def get_recommend_courses(self,row):
        recommend_list = []  # 空列表
        # row表示一行数据,  .all()表示取所有关联的书籍
        for item in row.coursedetail.recommend_courses.all():
            recommend_list.append({'id':item.id,'name':item.name})
            
        return recommend_list

View Code

重启2遍django项目，刷新页面，效果如下：

上面代码中的，列表里面添加字典数据，可以改成列表生成

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')
    # 显示推荐课程,对于多对多,使用def_字段名
    # SerializerMethodField表示序列化字段,使用方法获取
    recommend_courses = serializers.SerializerMethodField()

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours','recommend_courses']  # 指定序列化的字段

    def get_recommend_courses(self,row):
        recommend_list = row.coursedetail.recommend_courses.all()
        return [{'id': item.id, 'name': item.name} for item in recommend_list]

View Code

重启django项目，刷新页面，效果同上！

看下图中的代码

这个名字，必须一一对应，否则报错

因为源码里面定义了，它是取get_字段名方法的。

SerializerMethodField 拆分成3个单词：Serializer Method Field。可以理解为序列化，方法，字段

一对多

Course表的degree_course字段和DegreeCourse表示一对多关系

要显示总奖学金

修改serializers目录下course.py

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')
    # 显示推荐课程,对于多对多,使用def_字段名
    # SerializerMethodField表示序列化字段,使用方法获取
    recommend_courses = serializers.SerializerMethodField()
    # 显示总奖学金,使用表名.字段
    total_scholarship = serializers.CharField(source='degree_course.total_scholarship')

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours','recommend_courses','total_scholarship']  # 指定序列化的字段

    def get_recommend_courses(self,row):
        recommend_list = row.coursedetail.recommend_courses.all()
        return [{'id': item.id, 'name': item.name} for item in recommend_list]

View Code

刷新页面，效果如下：

contenttypes反向查询

Course表的price_policy字段和PricePolicy表，是用contenttypes关联的

from rest_framework import serializers
from api import models

class CourseSerializer(serializers.ModelSerializer):
    # 显示choices里面的中文
    level_cn = serializers.CharField(source='get_level_display')
    # 显示课时,对于一对一，使用表名.字段
    hours = serializers.CharField(source='coursedetail.hours')
    # 显示推荐课程,对于多对多,使用def_字段名
    # SerializerMethodField表示序列化字段,使用方法获取
    recommend_courses = serializers.SerializerMethodField()
    # 显示总奖学金,使用表名.字段
    total_scholarship = serializers.CharField(source='degree_course.total_scholarship')
    # 显示价格策略，contenttypes反向查询，使用def_字段名
    price_strategy = serializers.SerializerMethodField()

    class Meta:  # 配置项
        model = models.Course  # Course表
        fields = ['id','name','level_cn','hours','recommend_courses','total_scholarship','price_strategy']  # 指定序列化的字段

    def get_recommend_courses(self,row):
        recommend_list = row.coursedetail.recommend_courses.all()
        return [{'id': item.id, 'name': item.name} for item in recommend_list]

    def get_price_strategy(self,row):
        # .all 表示查询关联的价格策略
        price_list = row.price_policy.all()
        return [{'id': item.id, 'valid_period': item.valid_period,'price': item.price} for item in price_list]

View Code

重启django项目，刷新页面，效果如下：

总结：

序列化类

一对一，使用表名小写.字段名

一对多，使用表名小写.字段名

多对多，使用def_字段名。注意字段必须先声明为serializers.SerializerMethodField()。字段名和def_字段名必须一一对应！

contenttypes反向查询，使用def_字段名。利用contenttypes字段，也是要声明serializers.SerializerMethodField()...

作业

接口

# a.查看所有学位课并打印学位课名称以及授课老师

# b.查看所有学位课并打印学位课名称以及学位课的奖学金

# c.展示所有的专题课

# d. 查看id=1的学位课对应的所有模块名称

# e.获取id = 1的专题课，并打印：课程名、级别(中文)、why_study、what_to_study_brief、所有recommend_courses

# f.获取id = 1的专题课，并打印该课程相关的所有常见问题

# g.获取id = 1的专题课，并打印该课程相关的课程大纲

# h.获取id = 1的专题课，并打印该课程相关的所有章节

View Code

将上面几个查询改成接口方式，返回json格式。

注意：每一个查询，都是一个独立的接口

vue.js

通过axios向API发送ajax请求，并显示结果（展示所有的专题课）。

注意：会出现跨域问题。请自行百度！提示：搜索关键字cors

参考答案

接口

修改api_urls.py

from django.conf.urls import url
from api.views import course,degreecourse

urlpatterns = [
    url(r'courses/$',course.CoursesView.as_view()),
    url(r'courses/(?P<pk>d+)/$',course.CourseDetailView.as_view()),
    url(r'courses/thematic/$',course.CourseThematicView.as_view()),
    url(r'courses/module/(?P<pk>d+)/$',course.CourseModuleView.as_view()),
    url(r'courses/faq/(?P<pk>d+)/$',course.CourseFAQView.as_view()),
    url(r'courses/outline/(?P<pk>d+)/$',course.CourseOutlineView.as_view()),
    url(r'courses/chapter/(?P<pk>d+)/$',course.CourseChapterView.as_view()),

    url(r'degreecourse/$',degreecourse.DegreeCourseView.as_view()),
    url(r'degreecourse/teachers/$',degreecourse.DegreeCourseTeachersView.as_view()),
    url(r'degreecourse/scholarship/$',degreecourse.DegreeCourseScholarshipView.as_view()),
]

View Code

修改serializers目录下的course.py

from rest_framework import serializers
from api import models

class CourseModelSerializer(serializers.ModelSerializer):  # 所有课程
    level_name = serializers.CharField(source='get_level_display')
    hours = serializers.CharField(source='coursedetail.hours')
    course_slogan = serializers.CharField(source='coursedetail.course_slogan')
    recommend_courses = serializers.SerializerMethodField()

    class Meta:
        model = models.Course
        fields = ['id','name','level_name','hours','course_slogan','recommend_courses']

    def get_recommend_courses(self,row):
        recommend_list = row.coursedetail.recommend_courses.all()
        return [ {'id':item.id,'name':item.name} for item in recommend_list]

class CourseThematicModelSerializer(serializers.ModelSerializer):  # 所有的专题课
    level_name = serializers.CharField(source='get_level_display')
    course_type = serializers.CharField(source='get_course_type_display')
    status = serializers.CharField(source='get_status_display')
    degree_course = serializers.CharField(source='degree_course.total_scholarship')

    class Meta:
        model = models.Course
        fields = '__all__'

class CourseModuleModelSerializer(serializers.ModelSerializer):  # 所有的专题课
    degree_course = serializers.CharField(source='degree_course.name')
    class Meta:
        model = models.Course
        fields = ['id','degree_course']

class CourseDetailModelSerializer(serializers.ModelSerializer):  # 具体id的学位课对应的所有模块名称
    level_name = serializers.CharField(source='get_level_display')
    why_study = serializers.CharField(source='coursedetail.why_study')
    what_to_study_brief = serializers.CharField(source='coursedetail.what_to_study_brief')

    recommend_courses = serializers.SerializerMethodField()
    price_strategy = serializers.SerializerMethodField()

    class Meta:
        model = models.Course
        fields = ['id','name','level_name','why_study','what_to_study_brief','recommend_courses','price_strategy']

    def get_recommend_courses(self,row):
        recommend_list = row.coursedetail.recommend_courses.all()
        return [ {'id':item.id,'name':item.name} for item in recommend_list]

    def get_price_strategy(self,row):
        price_list = row.price_policy.all()
        return [{'id': item.id, 'valid_period': item.valid_period,'price': item.price} for item in price_list]

class CourseFAQModelSerializer(serializers.ModelSerializer):  # 具体id专题课程相关的所有常见问题
    asked_question = serializers.SerializerMethodField()

    class Meta:
        model = models.Course
        fields = ['id','name', 'asked_question']

    def get_asked_question(self, row):
        faq_list = row.asked_question.all()
        return [{'id': item.id, 'question': item.question, 'answer': item.answer} for item in faq_list]


class CourseOutlineModelSerializer(serializers.ModelSerializer):  # 具体id课程相关的课程大纲
    asked_question = serializers.SerializerMethodField()

    class Meta:
        model = models.Course
        fields = ['id', 'name', 'asked_question']

    def get_asked_question(self, row):
        outline_list = row.coursedetail.courseoutline_set.all()
        return [{'id': item.id, 'title': item.title, 'content': item.content} for item in outline_list]

class CourseChapterModelSerializer(serializers.ModelSerializer):  # 具体id课程相关的所有章节
    chapter = serializers.SerializerMethodField()

    class Meta:
        model = models.Course
        fields = ['id', 'name', 'chapter']

    def get_chapter(self, row):
        chapter_list = row.coursechapter_set.all()
        return [{'id': item.id, 'name': item.name} for item in chapter_list]

View Code

修改serializers目录下的degreecourse.py

from rest_framework import serializers
from api import models

class DegreeCourseModelSerializer(serializers.ModelSerializer):  # 学位课所有信息
    class Meta:
        model = models.DegreeCourse
        fields = '__all__'

class DegreeCourseTeachersModelSerializer(serializers.ModelSerializer):  # 学位课的老师
    teachers = serializers.SerializerMethodField()

    class Meta:
        model = models.DegreeCourse
        fields = ['name','teachers']

    def get_teachers(self,row):
        teachers_list = row.teachers.all()
        return [ {'id':item.id,'name':item.name} for item in teachers_list]

class DegreeCourseScholarshipModelSerializer(serializers.ModelSerializer):  # 学位课的奖学金
    degreecourse_price_policy = serializers.SerializerMethodField()
    class Meta:
        model = models.DegreeCourse
        fields = ['name','degreecourse_price_policy']

    def get_degreecourse_price_policy(self,row):
        scholarships = row.scholarship_set.all()
        return [ {'id':item.id,'time_percent':item.time_percent,'value':item.value} for item in scholarships]

View Code

在api目录下utils文件夹，创建文件serialization_general.py

from api.utils.response import BaseResponse
from rest_framework.pagination import PageNumberPagination

class SerializedData(object):  # 序列化通用格式数据
    def __init__(self,request,queryset,serializer_class):
        self.request = request
        self.queryset = queryset
        self.serializer_class = serializer_class


    def get_data(self):
        ret = BaseResponse()
        try:
            # 从数据库获取数据
            queryset = self.queryset.order_by('id')

            # 分页
            page = PageNumberPagination()
            course_list = page.paginate_queryset(queryset, self.request, self)

            # 分页之后的结果执行序列化
            ser = self.serializer_class(instance=course_list, many=True)

            ret.data = ser.data
        except Exception as e:
            print(e)
            ret.code = 500
            ret.error = '获取数据失败'

        return ret.dict

View Code

修改views目录下的course.py

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.versioning import URLPathVersioning
from rest_framework.pagination import PageNumberPagination

from api import models
from api.serializers.course import CourseModelSerializer, CourseThematicModelSerializer, CourseModuleModelSerializer, 
    CourseDetailModelSerializer,CourseFAQModelSerializer,CourseOutlineModelSerializer,CourseChapterModelSerializer
from api.utils.response import BaseResponse
from api.utils.serialization_general import SerializedData

class CoursesView(APIView):  # 所有课程,分页展示,每页1个

    def get(self, request, *args, **kwargs):
        # response = {'code':1000,'data':None,'error':None}
        queryset = models.Course.objects.all()
        serializer_class = CourseModelSerializer
        data = SerializedData(request,queryset,serializer_class).get_data()
        return Response(data)


class CourseDetailView(APIView):  # 课程详情
    def get(self, request, pk, *args, **kwargs):
        queryset = models.Course.objects.filter(id=pk)
        serializer_class = CourseDetailModelSerializer
        data = SerializedData(request, queryset, serializer_class).get_data()
        return Response(data)



class CourseThematicView(APIView):  # 所有的专题课
    def get(self, request, *args, **kwargs):
        queryset = models.Course.objects.all()
        serializer_class = CourseThematicModelSerializer
        data = SerializedData(request, queryset, serializer_class).get_data()
        return Response(data)


class CourseModuleView(APIView):  # 具体id的学位课对应的所有模块名称
    def get(self, request, pk, *args, **kwargs):
        queryset = models.Course.objects.filter(degree_course_id=pk)
        serializer_class = CourseModuleModelSerializer
        data = SerializedData(request, queryset, serializer_class).get_data()
        return Response(data)


class CourseFAQView(APIView):  # 具体id的课程相关的所有常见问题
    def get(self, request, pk, *args, **kwargs):
        queryset = models.Course.objects.filter(id=pk)
        serializer_class = CourseFAQModelSerializer
        data = SerializedData(request, queryset, serializer_class).get_data()
        return Response(data)


class CourseOutlineView(APIView):  # 具体id课程相关的课程大纲
    def get(self, request, pk, *args, **kwargs):
        queryset = models.Course.objects.filter(id=pk)
        serializer_class = CourseOutlineModelSerializer
        data = SerializedData(request, queryset, serializer_class).get_data()
        return Response(data)


class CourseChapterView(APIView):  # 具体id课程相关的所有章节
    def get(self, request, pk, *args, **kwargs):
        queryset = models.Course.objects.filter(id=pk)
        serializer_class = CourseChapterModelSerializer
        data = SerializedData(request, queryset, serializer_class).get_data()
        return Response(data)

View Code

在views目录下创建文件degreecourse.py

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.versioning import URLPathVersioning
from rest_framework.pagination import PageNumberPagination

from api import models
from api.serializers.degreecourse import DegreeCourseModelSerializer,DegreeCourseTeachersModelSerializer
from api.serializers.degreecourse import DegreeCourseScholarshipModelSerializer
from api.utils.response import BaseResponse

class DegreeCourseView(APIView):  # 所有学位课

    def get(self,request,*args,**kwargs):
        # response = {'code':1000,'data':None,'error':None}
        ret = BaseResponse()
        try:
            # 从数据库获取数据
            queryset = models.DegreeCourse.objects.all()

            # 分页
            page = PageNumberPagination()
            course_list = page.paginate_queryset(queryset,request,self)

            # 分页之后的结果执行序列化
            ser = DegreeCourseModelSerializer(instance=course_list,many=True)

            ret.data = ser.data
        except Exception as e:
            ret.code = 500
            ret.error = '获取数据失败'

        return Response(ret.dict)


class DegreeCourseTeachersView(APIView):  # 学位课对应的老师
    def get(self, request, *args, **kwargs):
        ret = BaseResponse()
        try:
            # 从数据库获取数据
            # 防止出现UnorderedObjectListWarning: Pagination may yield...
            queryset = models.DegreeCourse.objects.get_queryset().order_by('id')
            print(queryset)
            # 分页
            page = PageNumberPagination()
            course_list = page.paginate_queryset(queryset, request, self)

            # 分页之后的结果执行序列化
            ser = DegreeCourseTeachersModelSerializer(instance=course_list, many=True)
            print(ser.data)

            ret.data = ser.data
        except Exception as e:

            print(e)

            ret.code = 500
            ret.error = '获取数据失败'

        return Response(ret.dict)

class DegreeCourseScholarshipView(APIView):  # 学位课对应的老师
    def get(self, request, *args, **kwargs):
        ret = BaseResponse()
        try:
            # 从数据库获取数据
            # 防止出现UnorderedObjectListWarning: Pagination may yield...
            queryset = models.DegreeCourse.objects.get_queryset().order_by('id')
            print(queryset)
            # 分页
            page = PageNumberPagination()
            course_list = page.paginate_queryset(queryset, request, self)

            # 分页之后的结果执行序列化
            ser = DegreeCourseScholarshipModelSerializer(instance=course_list, many=True)
            print(ser.data)

            ret.data = ser.data
        except Exception as e:

            print(e)

            ret.code = 500
            ret.error = '获取数据失败'

        return Response(ret.dict)

View Code

访问以下url:

查看所有学位课并打印学位课名称以及授课老师

http://127.0.0.1:8000/api/v1/degreecourse/teachers/

查看所有学位课并打印学位课名称以及学位课的奖学金

http://127.0.0.1:8000/api/v1/degreecourse/scholarship/

展示所有的专题课

http://127.0.0.1:8000/api/v1/courses/thematic/

查看id=1的学位课对应的所有模块名称

http://127.0.0.1:8000/api/v1/courses/module/1/

获取id = 1的专题课，并打印：课程名、级别(中文)、why_study、what_to_study_brief、所有recommend_courses

http://127.0.0.1:8000/api/v1/courses/1/

获取id = 1的专题课，并打印该课程相关的所有常见问题

http://127.0.0.1:8000/api/v1/courses/faq/1/

coursedetail获取id = 1的专题课，并打印该课程相关的课程大纲

http://127.0.0.1:8000/api/v1/courses/outline/1/

获取id = 1的专题课，并打印该课程相关的所有章节

http://127.0.0.1:8000/api/v1/courses/chapter/1/

vue.js

在cmd中进入一个空目录，输入下面的命令，创建一个项目mysite

vue init webpack mysite

执行之后有很多选项，详情请参考：

https://www.cnblogs.com/xiao987334176/p/9372479.html#autoid-5-1-0

执行2个命令，启动vue项目

cd mysite
npm run dev

访问vue的网页：http://localhost:8080

进入vue项目，里面有一个index.html，它是最大的母版。

里面定义了一个div，id为app

进入src目录，修改App.vue。删除图片和css样式

<template>
  <div id="app">

    <router-view/>
  </div>
</template>

<script>
export default {
  name: 'App'
}
</script>

<style>

</style>

View Code

进入src-->components，修改HelloWorld.vue，删除多余的a标签

<template>
  <div class="hello">
    <h1>{{ msg }}</h1>
  </div>
</template>

<script>
export default {
  name: 'HelloWorld',
  data () {
    return {
      msg: '欢迎使用路飞学城'
    }
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
h1, h2 {
  font-weight: normal;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  display: inline-block;
  margin: 0 10px;
}
a {
  color: #42b983;
}
</style>

View Code

关闭vue项目，安装axios

npm install axios --save

重新启动vue项目

npm run dev

修改main.js，导入axios，并定义一个全局变量$axios

// The Vue build version to load with the `import` command
// (runtime-only or standalone) has been set in webpack.base.conf with an alias.
import Vue from 'vue'
import App from './App'
import router from './router'
import axios from 'axios'  //导入axios

Vue.prototype.$axios = axios  //声明全局变量
Vue.config.productionTip = false

/* eslint-disable no-new */
new Vue({
  el: '#app',
  router,
  components: { App },
  template: '<App/>'
})

View Code

进入src-->components，修改HelloWorld.vue。让页面加载完成后，使用axios发送请求

<template>
  <div class="hello">
    <h1>{{ msg }}</h1>
  </div>
</template>

<script>
export default {
  name: 'HelloWorld',
  data () {
    return {
      msg: '欢迎使用路飞学城'
    }
  },
  mounted(){  //页面加载完成后
    this.initCourse();  //执行此方法
  },
  methods:{
    initCourse:function () {
      //向后台发送ajax请求
      this.$axios.request({
        url:'http://127.0.0.1:8000/api/v1/courses/',
        method:'GET',
        responseType:'json',
      }).then(function (arg) {
        //成功之后
        console.log(arg);
      }).catch(function (err) {
        //发生错误
        console.log(err);
      })
    }
  },
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
h1, h2 {
  font-weight: normal;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  display: inline-block;
  margin: 0 10px;
}
a {
  color: #42b983;
}
</style>

View Code

刷新网页，查看Console，提示不允许访问

只要看到了Access-Control-Allow-Origin，就表示出现跨域了

关于跨域问题，如何解决。请访问下一篇文章：

https://www.cnblogs.com/xiao987334176/articles/9457580.html