Django学习笔记

环境：

• DataBase：mysql5.7 community
• mysql 下载地址：https://dev.mysql.com/downloa…
• 开发语言：Python 3.7.3 64bit
• 下载 mysql 驱动：https://www.lfd.uci.edu/~gohl…
• admin 后台优化：django-xadmin
• django 安装：pip install django==2.2 -i https://pypi.douban.com/simple
• 镜像安装：https://pypi.douban.com/simple，例：pip install django==2.2 -i https://pypi.douban.com/simple
• captcha 插件：django simple captcha https://django-simple-captcha…
• redis windows：https://github.com/ServiceSta…
• redis python 驱动：https://github.com/andymccurd…
• 分页插件：django pure pagination https://github.com/jamespacil…

技术点：

• format 格式化

>>>"{} {}".format("hello", "world")    # 不设置指定位置，按默认顺序
'hello world'
 
>>> "{0} {1}".format("hello", "world")  # 设置指定位置
'hello world'
 
>>> "{1} {0} {1}".format("hello", "world")  # 设置指定位置
'world hello world'

• http 数据传给前端

from django.http import HttpResponseRedirect, JsonResponse

return JsonResponse({})

• FORM 字段单独验证

class RegisterPostForm(forms.Form):
    mobile = forms.CharField(required=True, min_length=11, max_length=11)
    code = forms.CharField(required=True, min_length=4, max_length=4)
    password = forms.CharField(required=True)

    # 验证手机号是否已注册
    def clean_mobile(self):
        mobile = self.data.get("mobile")
        user = UserProfile.objects.filter(mobile=mobile)
        if user:
            raise forms.ValidationError("该手机号已被注册")
        return mobile

• 防止 basemodel 字段生成表

class BaseModel(models.Model):
    add_time = models.DateTimeField(default=datetime.now, verbose_name="添加时间")

    class Meta:
        # 防止 BaseModel 生成表
        abstract = True

• django 内置用户密码加密方法

user = UserProfile(mobile=mobile)
user.set_passdjangoword(password)  # set_password 生成加密后的密码 

• HttpResponseRedirect 页面重定向跳转

if user is not None:
    # 查询到用户
    login(request, user)
    # HttpResponseRedirect 页面重定向
    return HttpResponseRedirect(reverse("index"))

• model 外键定义

class Lesson(BaseModel):
    # on_delete 表示对应的外键数据被删除后，当前的数据应该怎么办
    # 值为 models.SET_NULL 不级联删除，还需参数 null=True, blank=True。值为 models.CASCADE 会级联删除
    # course = models.ForeignKey(Course, on_delete=models.SET_NULL, null=True, blank=True)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    name = models.CharField(verbose_name="章节名", max_length=100)
    learn_times = models.IntegerField(verbose_name="学习时长 ( 分钟数)", default=0)

    class Meta:
        verbose_name = "课程章节"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name

• 分页

class CourseListView(View):
    def get(self, request, *args, **kwargs):
        # 获取课程列表
        all_courses = Course.objects.all().order_by("-add_time")

        # 对课程数据进行分页
        try:
            page = request.GET.get('page', 1)
        except PageNotAnInteger:
            page = 1

        p = Paginator(all_courses, per_page=5, request=request)

        courses = p.page(page)

        return render(request, "course-list.html", {"all_courses": courses})


# 注意 all_courses.object_list
{% for course in all_courses.object_list %}
{% endfor %}

<div class="pageturn">
    <ul class="pagelist">

        {% if all_courses.has_previous %}
            <li class="long"><a href="?{{all_courses.previous_page_number.querystring}}"> 上一页 </a>
            </li>
        {% endif %}
        {% for page in all_courses.pages %}
            {% if page %}
                {% ifequal page all_courses.number %}
                    <li class="active"><a href="?{{page.querystring}}">{{page}}</a></li>
                {% else %}
                    <li><a href="?{{page.querystring}}" class="page">{{page}}</a></li>
                {% endifequal %}
            {% else %}
                <li class="none">...</li>
            {% endif %}
        {% endfor %}
        {% if all_courses.has_next %}
            <li class="long"><a
                    href="?{{all_courses.next_page_number.querystring}}"> 下一页 </a></li>
        {% endif %}
    </ul>
</div>

• 取外键属性值

<!-- 外键查找属性 查找课程外键课程机构的名称 -->
<a href="course-detail.html">
    <span class="fl"> 来自 {{course.course_org.name}}</span>
</a>

• model 数据查询倒序

# order_by 倒序字段前加“-”all_courses = Course.objects.all().order_by("-add_time")

• template 对 model charfiled choices 取值

# model
class Course(BaseModel):
    degree = models.CharField(verbose_name="难度", choices=(("cj", "初级"), ("zj", "中级"), ("gj", "高级")), max_length=2)

# html
难度：<i class="key">{{course.get_degree_display}}</i>

• template media_url 拼接

<img src="{{course.image.url}}"/>
# 等同于
<img src="{{MEDIA_URL}}{{course.image}}"/>

• url 中设置参数字段获取

urlpatterns = [url(r'(?P<course_id>\d+)/detail/$', CourseDetailView.as_view(), name='detail'),
]

class CourseDetailView(View):
    def get(self, request, course_id, *args, **kwargs):
        pass

• 字典循环取数据快捷写法

user_courses = UserCourse.objects.filter(course=course)
user_ids = [user_course.user.id for user_course in user_courses]

• template for 循环取索引下标

{% for teacher in hot_teachers %}
# forloop.counter0 会得到从 0 开始计算的下标
# forloop.counter 会得到从 1 开始计算的下标
<span class="num fl">{{forloop.counter}}</span>
{% endfor %}

• template 过滤处理

<input type="text" value="{{user.birthday|default_if_none:''|date:'Y-m-d'}}"/>