stark组件（2）：提取公共视图函数、URL分发和设置别名

效果图：

Handler类里处理的增删改查、路由分发、给URL设置别名等包括以后还要添加的很多功能，每一个数据库的类都需要，所以我们要把Handler提取成一个基类。提取成基类后，每一个数据表都可以继承这个基类，然后有需要的话可以在这个基类的基础上重写函数，定制自己的方法。

Handler下新增函数get_urls是为了解耦Stark类下的get_urls

一、stark组件

stark/service/core_func.py

from django.urls import re_path
from django.shortcuts import HttpResponse, render

class StarkHandler(object):
    def __init__(self, model_class, prev=None):
        self.model_class = model_class
        self.prev = prev

    def list_view(self, request):
        """
        列表页面
        :param request:
        :return:
        """
        data_list = self.model_class.objects.all()
        return render(request, 'stark/data_list.html', {'data_list': data_list})

    def add_view(self, request):
        """
        添加页面
        :param request:
        :return:
        """
        return HttpResponse('添加页面')

    def edit_view(self, request, pk):
        """
        编辑页面
        :param request:
        :return:
        """
        return HttpResponse('编辑页面')

    def delete_view(self, request, pk):
        """
        删除页面
        :param request:
        :param pk:
        :return:
        """
        return HttpResponse('删除页面')

    def get_urls(self):
        app_name, model_name = self.model_class._meta.app_label, self.model_class._meta.model_name
        if self.prev:
            patterns = [
                re_path(r'^list/$', self.list_view, name="%s_%s_%s_list" % (app_name, model_name, self.prev)),
                re_path(r'^add/$', self.add_view, name="%s_%s_%s_add" % (app_name, model_name, self.prev)),
                re_path(r'^edit/(\d+)/$', self.edit_view, name="%s_%s_%s_edit" % (app_name, model_name, self.prev)),
                re_path(r'^delete/(\d+)/$', self.delete_view,
                        name="%s_%s_%s_delete" % (app_name, model_name, self.prev)),
            ]
        else:
            patterns = [
                re_path(r'^list/$', self.list_view, name="%s_%s_list" % (app_name, model_name,)),
                re_path(r'^add/$', self.add_view, name="%s_%s_add" % (app_name, model_name,)),
                re_path(r'^edit/(\d+)/$', self.edit_view, name="%s_%s_edit" % (app_name, model_name,)),
                re_path(r'^delete/(\d+)/$', self.delete_view,
                        name="%s_%s_delete" % (app_name, model_name,)),
            ]
        patterns.extend(self.extra_urls())
        return patterns

    def extra_urls(self):
        return []

class StarkSite(object):
    def __init__(self):
        self._registry = []
        self.app_name = 'stark'
        self.namespace = 'stark'

    def register(self, model_class, handler_class=None, prev=None):
        """
        :param model_class: 是models中的数据库表对应的类。
        :param handler_class: 处理请求的视图函数所在的类
        :param prev: 生成URL的前缀
        :return:
        """

        if not handler_class:
            handler_class = StarkHandler
        self._registry.append({'model_class': model_class, 'handler': handler_class(model_class, prev), 'prev': prev})

    def get_urls(self):
        patterns = []
        for item in self._registry:
            model_class = item['model_class']
            handler = item['handler']
            prev = item['prev']
            app_name, model_name = model_class._meta.app_label, model_class._meta.model_name
            if prev:
                patterns.append(
                    re_path(r'^%s/%s/%s/' % (app_name, model_name, prev,), (handler.get_urls(), None, None)))
            else:
                patterns.append(re_path(r'^%s/%s/' % (app_name, model_name,), (handler.get_urls(), None, None)))

        return patterns

    @property
    def urls(self):
        return self.get_urls(), self.app_name, self.namespace

site = StarkSite()

二、业务处理

web/stark.py

from django.urls import re_path

from django.shortcuts import HttpResponse
from stark.service.core_func import site, StarkHandler

from web import models

class DepartmentHandler(StarkHandler):
    def extra_urls(self):
        """
        增加额外的URL
        :return:
        """
        # 给部门增加了详情页：/stark/web/department/private/detail/1
        return [
            re_path(r'^detail/(\d+)', self.detail_view)
        ]

    def detail_view(self, request, pk):
        return HttpResponse('详细页面')

class UserInfoHandler(StarkHandler):
    def get_urls(self):
        """
        修改url
        :return:
        """
        # 用户信息只有list和add的url
        patterns = [
            re_path(r'^list/$', self.list_view),
            re_path(r'^add/$', self.add_view),
        ]

        return patterns

site.register(models.Department, DepartmentHandler, prev='private')  # 给部门的url增加了前缀：/stark/web/department/private/
site.register(models.UserInfo, UserInfoHandler)