Python学习（三十六）—— Cookie、Session和自定义分页
一、Django中操作Cookie
获取Cookie
request.COOKIES['key'] request.get_signed_cookie(key, default=RAISE_ERROR, salt='', max_age=None)
参数：
- default: 默认值
- salt: 加密盐
- max_age: 后台控制过期时间
设置Cookie
rep = HttpResponse(...) rep ＝ render(request, ...) rep.set_cookie(key,value,...) rep.set_signed_cookie(key,value,salt='加密盐',...)
参数：
- key, 键
- value='', 值
- max_age=None, 超时时间
- expires=None, 超时时间(IE requires expires, so set it if hasn't been already.)
- path='/', Cookie生效的路径，/ 表示根路径，特殊的：根路径的cookie可以被任何url的页面访问
- domain=None, Cookie生效的域名
- secure=False, https传输
- httponly=False 只能http协议传输，无法被JavaScript获取（不是绝对，底层抓包可以获取到也可以被覆盖）
Cookie版登陆校验
def check_login(func): @wraps(func) def inner(request, *args, **kwargs): next_url = request.get_full_path() if request.get_signed_cookie("login", salt="SSS", default=None) == "yes": # 已经登录的用户... return func(request, *args, **kwargs) else: # 没有登录的用户，跳转刚到登录页面 return redirect("/login/?next={}".format(next_url)) return inner def login(request): if request.method == "POST": username = request.POST.get("username") passwd = request.POST.get("password") if username == "xxx" and passwd == "dashabi": next_url = request.GET.get("next") if next_url and next_url != "/logout/": response = redirect(next_url) else: response = redirect("/class_list/") response.set_signed_cookie("login", "yes", salt="SSS") return response return render(request, "login.html")
二、Session
Django中默认支持Session，其内部提供了5种类型的Session供开发者使用：
- 数据库（默认）
- 缓存
- 文件
- 缓存+数据库
- 加密cookie
数据库Session
SESSION_ENGINE = 'django.contrib.sessions.backends.db' # 引擎（默认）
缓存Session
SESSION_ENGINE = 'django.contrib.sessions.backends.cache' # 引擎 SESSION_CACHE_ALIAS = 'default' # 使用的缓存别名（默认内存缓存，也可以是memcache），此处别名依赖缓存的设置
文件Session
SESSION_ENGINE = 'django.contrib.sessions.backends.file' # 引擎 SESSION_FILE_PATH = None # 缓存文件路径，如果为None，则使用tempfile模块获取一个临时地址tempfile.gettempdir()
缓存+数据库
SESSION_ENGINE = 'django.contrib.sessions.backends.cached_db' # 引擎
加密Cookie Session
SESSION_ENGINE = 'django.contrib.sessions.backends.signed_cookies' # 引擎
其他公用设置项：
SESSION_COOKIE_NAME ＝ "sessionid" # Session的cookie保存在浏览器上时的key，即：sessionid＝随机字符串（默认） SESSION_COOKIE_PATH ＝ "/" # Session的cookie保存的路径（默认） SESSION_COOKIE_DOMAIN = None # Session的cookie保存的域名（默认） SESSION_COOKIE_SECURE = False # 是否Https传输cookie（默认） SESSION_COOKIE_HTTPONLY = True # 是否Session的cookie只支持http传输（默认） SESSION_COOKIE_AGE = 1209600 # Session的cookie失效日期（2周）（默认） SESSION_EXPIRE_AT_BROWSER_CLOSE = False # 是否关闭浏览器使得Session过期（默认） SESSION_SAVE_EVERY_REQUEST = False # 是否每次请求都保存Session，默认修改之后才保存（默认）
不管你怎么设置Session，使用方式都一样：
def index(request): # 获取、设置、删除Session中数据 request.session['k1'] request.session.get('k1',None) request.session['k1'] = 123 request.session.setdefault('k1',123) # 存在则不设置 del request.session['k1'] # 所有 键、值、键值对 request.session.keys() request.session.values() request.session.items() request.session.iterkeys() request.session.itervalues() request.session.iteritems() # 用户session的随机字符串 request.session.session_key # 将所有Session失效日期小于当前日期的数据删除 request.session.clear_expired() # 检查 用户session的随机字符串 在数据库中是否 request.session.exists("session_key") # 删除当前用户的所有Session数据 request.session.delete("session_key") request.session.set_expiry(value) * 如果value是个整数，session会在些秒数后失效。 * 如果value是个datatime或timedelta，session就会在这个时间后失效。 * 如果value是0,用户关闭浏览器session就会失效。 * 如果value是None,session会依赖全局session失效策略。
课后练习：Session版登陆验证
CBV中加装饰器相关
from django.utils.decorators import method_decorator
1. 加在get或post方法上
class LoginView(View): def dispatch(self, request, *args, **kwargs): return super(LoginView,self).dispatch(request, *args, **kwargs) def get(self,request): return render(request,'login.html') @method_decorator(test) def post(self,request): user = request.POST.get('user') pwd = request.POST.get('pwd') if user == 'alex' and pwd == "alex3714": # 生成随机字符串 # 写浏览器cookie： session_id: 随机字符串 # 写到服务端session： # { # "随机字符串": {'user_info':'alex} # } request.session['user_info'] = "alex" return redirect('/index/') return render(request, 'login.html')
2. 加在dispatch方法上
class LoginView(View): @method_decorator(test) def dispatch(self, request, *args, **kwargs): return super(LoginView, self).dispatch(request, *args, **kwargs) def get(self, request): return render(request, 'login.html') def post(self, request): user = request.POST.get('user') pwd = request.POST.get('pwd') if user == 'alex' and pwd == "alex3714": # 生成随机字符串 # 写浏览器cookie： session_id: 随机字符串 # 写到服务端session： # { # "随机字符串": {'user_info':'alex} # } request.session['user_info'] = "alex" return redirect('/index/') return render(request, 'login.html')
3. 加在类上
@method_decorator(test,name='get') class LoginView(View): def dispatch(self, request, *args, **kwargs): return super(LoginView,self).dispatch(request, *args, **kwargs) def get(self,request): return render(request,'login.html') def post(self,request): user = request.POST.get('user') pwd = request.POST.get('pwd') if user == 'alex' and pwd == "alex3714": # 生成随机字符串 # 写浏览器cookie： session_id: 随机字符串 # 写到服务端session： # { # "随机字符串": {'user_info':'alex} # } request.session['user_info'] = "alex" return redirect('/index/) return render(request, 'login.html')
4. CSRF Token相关只能加到dispatch方法上
from django.views.decorators.csrf import csrf_exempt, csrf_protect class LoginView(View): @method_decorator(csrf_exempt) def dispatch(self, request, *args, **kwargs): return super(LoginView,self).dispatch(request, *args, **kwargs) def get(self,request): return render(request,'login.html') def post(self,request): user = request.POST.get('user') pwd = request.POST.get('pwd') if user == 'alex' and pwd == "alex3714": # 生成随机字符串 # 写浏览器cookie： session_id: 随机字符串 # 写到服务端session： # { # "随机字符串": {'user_info':'alex} # } request.session['user_info'] = "alex" return redirect('/index/') return render(request, 'login.html')
三、自定义分页
稳扎稳打版
data = [] for i in range(1, 302): tmp = {"id": i, "name": "alex-{}".format(i)} data.append(tmp) print(data) def user_list(request): # user_list = data[0:10] # user_list = data[10:20] try: current_page = int(request.GET.get("page")) except Exception as e: current_page = 1 per_page = 10 # 数据总条数 total_count = len(data) # 总页码 total_page, more = divmod(total_count, per_page) if more: total_page += 1 # 页面最多显示多少个页码 max_show = 11 half_show = int((max_show-1)/2) if current_page <= half_show: show_start = 1 show_end = max_show else: if current_page + half_show >= total_page: show_start = total_page - max_show show_end = total_page else: show_start = current_page - half_show show_end = current_page + half_show # 数据库中获取数据 data_start = (current_page - 1) * per_page data_end = current_page * per_page user_list = data[data_start:data_end] # 生成页面上显示的页码 page_html_list = [] # 加首页 first_li = '<li><a href="/user_list/?page=1">首页</a></li>' page_html_list.append(first_li) # 加上一页 if current_page == 1: prev_li = '<li><a href="#">上一页</a></li>' else: prev_li = '<li><a href="/user_list/?page={}">上一页</a></li>'.format(current_page - 1) page_html_list.append(prev_li) for i in range(show_start, show_end+1): if i == current_page: li_tag = '<li class="active"><a href="/user_list/?page={0}">{0}</a></li>'.format(i) else: li_tag = '<li><a href="/user_list/?page={0}">{0}</a></li>'.format(i) page_html_list.append(li_tag) # 加下一页 if current_page == total_page: next_li = '<li><a href="#">下一页</a></li>' else: next_li = '<li><a href="/user_list/?page={}">下一页</a></li>'.format(current_page+1) page_html_list.append(next_li) # 加尾页 page_end_li = '<li><a href="/user_list/?page={}">尾页</a></li>'.format(total_page) page_html_list.append(page_end_li) page_html = "".join(page_html_list) return render(request, "user_list.html", {"user_list": user_list, "page_html": page_html})
封装保存版
class Pagination(object): def __init__(self, current_page, total_count, base_url, per_page=10, max_show=11): """ :param current_page: 当前页 :param total_count: 数据库中数据总数 :param per_page: 每页显示多少条数据 :param max_show: 最多显示多少页 """ try: current_page = int(current_page) except Exception as e: current_page = 1 self.current_page = current_page self.total_count = total_count self.base_url = base_url self.per_page = per_page self.max_show = max_show # 总页码 total_page, more = divmod(total_count, per_page) if more: total_page += 1 half_show = int((max_show - 1) / 2) self.half_show = half_show self.total_page = total_page @property def start(self): return (self.current_page - 1) * self.per_page @property def end(self): return self.current_page * self.per_page def page_html(self): if self.current_page <= self.half_show: show_start = 1 show_end = self.max_show else: if self.current_page + self.half_show >= self.total_page: show_start = self.total_page - self.max_show show_end = self.total_page else: show_start = self.current_page - self.half_show show_end = self.current_page + self.half_show # 生成页面上显示的页码 page_html_list = [] # 加首页 first_li = '<li><a href="{}?page=1">首页</a></li>'.format(self.base_url) page_html_list.append(first_li) # 加上一页 if self.current_page == 1: prev_li = '<li><a href="#">上一页</a></li>' else: prev_li = '<li><a href="{0}?page={1}">上一页</a></li>'.format(self.base_url, self.current_page - 1) page_html_list.append(prev_li) for i in range(show_start, show_end + 1): if i == self.current_page: li_tag = '<li class="active"><a href="{0}?page={1}">{1}</a></li>'.format(self.base_url, i) else: li_tag = '<li><a href="{0}?page={1}">{1}</a></li>'.format(self.base_url, i) page_html_list.append(li_tag) # 加下一页 if self.current_page == self.total_page: next_li = '<li><a href="#">下一页</a></li>' else: next_li = '<li><a href="{0}?page={1}">下一页</a></li>'.format(self.base_url, self.current_page + 1) page_html_list.append(next_li) # 加尾页 page_end_li = '<li><a href="{0}?page={1}">尾页</a></li>'.format(self.base_url, self.total_page) page_html_list.append(page_end_li) return "".join(page_html_list)
封装保存版使用指南
def user_list(request): pager = Pagination(request.GET.get("page"), len(data), request.path_info) user_list = data[pager.start:pager.end] page_html = pager.page_html() return render(request, "user_list.html", {"user_list": user_list, "page_html": page_html})
扩展：
Django内置分页
内置分页view部分
from django.shortcuts import render from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger L = [] for i in range(999): L.append(i) def index(request): current_page = request.GET.get('p') paginator = Paginator(L, 10) # per_page: 每页显示条目数量 # count: 数据总个数 # num_pages:总页数 # page_range:总页数的索引范围，如: (1,10),(1,200) # page: page对象 try: posts = paginator.page(current_page) # has_next 是否有下一页 # next_page_number 下一页页码 # has_previous 是否有上一页 # previous_page_number 上一页页码 # object_list 分页之后的数据列表 # number 当前页 # paginator paginator对象 except PageNotAnInteger: posts = paginator.page(1) except EmptyPage: posts = paginator.page(paginator.num_pages) return render(request, 'index.html', {'posts': posts})
内置分页HTML部分
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title></title> </head> <body> <ul> {% for item in posts %} <li>{{ item }}</li> {% endfor %} </ul> <div class="pagination"> <span class="step-links"> {% if posts.has_previous %} <a href="?p={{ posts.previous_page_number }}">Previous</a> {% endif %} <span class="current"> Page {{ posts.number }} of {{ posts.paginator.num_pages }}. </span> {% if posts.has_next %} <a href="?p={{ posts.next_page_number }}">Next</a> {% endif %} </span> </div> </body> </html>
