strak组件（3）：URL别名的优化

将生成URL别名的功能进行解耦。效果和上一节的一样。

效果图：

新增函数

get_url_name(self, param)   # 生成url别名，需要一个参数（list/add/edit/delete）
get_list_url_name(self)  # 获取列表页面URL的name  property
get_add_url_name(self)  # 获取添加页面URL的name  property
get_edit_url_name(self)  # 获取编辑页面URL的name  property
get_delete_url_name(self)  # 获取删除页面URL的name  property

Stark组件

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

class StarkHandler(object):
    def __init__(self, model_class, prev):
        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_url_name(self, crud):
        app_label, model_name = self.model_class._meta.app_label, self.model_class._meta.model_name
        if self.prev:
            return '%s_%s_%s_%s' % (app_label, model_name, self.prev, crud)
        return '%s_%s_%s' % (app_label, model_name, crud)

    @property
    def get_list_url_name(self):
        """
        获取列表页面URL的name
        :return:
        """
        return self.get_url_name('list')

    @property
    def get_add_url_name(self):
        """
        获取添加页面URL的name
        :return:
        """
        return self.get_url_name('add')

    @property
    def get_edit_url_name(self):
        """
        获取编辑页面URL的name
        :return:
        """
        return self.get_url_name('edit')

    @property
    def get_delete_url_name(self):
        """
        获取删除页面URL的name
        :return:
        """
        return self.get_url_name('delete')

    def get_urls(self):
        patterns = [
            re_path(r'^list/$', self.list_view, name=self.get_list_url_name),
            re_path(r'^add/$', self.add_view, name=self.get_add_url_name),
            re_path(r'^edit/(\d+)/$', self.edit_view, name=self.get_edit_url_name),
            re_path(r'^delete/(\d+)/$', self.delete_view, name=self.get_delete_url_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()