Python Day71 Django Pagination and session Introduction

One, Django paging

The following examples are custom paging:

"" "Pagination Component use Example: Def index (request): obj = pagination (request). Get.get (' page ', 1), Len (user_list), request.path_info) page_user_list = user_list[obj.start:obj.end] page_html = OBJ.PA Ge_html () return render (Request, ' index.html ', {' users ':p age_user_list, ' page_html ':p age_html}) "" "Class pagination (        Object): Def __init__ (self,current_page,all_count,base_url,per_page_num=10,pager_count=11): "" "encapsulates paging-related data  :p Aram Current_page: Current page:p Aram All_count: Total number of data bars in the database:p Aram Per_page_num: Number of data bars per page:p Aram Base_url: URL prefixes displayed in pagination:p Aram Pager_count: Maximum number of page numbers "" "Try:current_page = Int (current_        page) except Exception as E:current_page = 1 if current_page <1:current_page = 1 Self.current_page = Current_page Self.all_count = All_count Self.per_page_num = per_page_num s Elf.base_url = base_url # Total page number All_pager, tmp = Divmod (All_count, Per_page_num)       If Tmp:all_pager + = 1 Self.all_pager = All_pager Self.pager_count = Pager_count SE lf.pager_count_half = Int ((pager_count-1)/2) @property def start (self): return (self.current_page-1) * Self.per_page_num @property def End (self): return self.current_page * self.per_page_num def page_html (self ): # If total page number < 11: if Self.all_pager <= self.pager_count:pager_start = 1 pager_e nd = Self.all_pager + 1 # Total page number > all else: # current page If the <= page shows a maximum of 11/2 pages if Self.curren            T_page <= Self.pager_count_half:pager_start = 1 Pager_end = self.pager_count + 1 # The current page is greater than 5 else: # page number turns to last if (Self.current_page + self.pager_count_half) > S Elf.all_pager:pager_end = Self.all_pager + 1 Pager_start = SELF.ALL_PAGER-SELF.PA           Ger_count + 1     Else:pager_start = Self.current_page-self.pager_count_half Pager_end = self. Current_page + self.pager_count_half + 1 page_html_list = [] first_page = ' <li><a href= '%s?page=%s ' > Home </a></li> '% (self.base_url,1,) page_html_list.append (first_page) if Self.current_page &lt = 1:prev_page = ' <li><a href= ' # ' > prev </a></li> ' else:prev_page = ' & Lt;li><a href= "%s?page=%s" > Previous </a></li> '% (self.base_url,self.current_page-1,) Page_html_li St.append (prev_page) for I in range (Pager_start, pager_end): if i = = Self.current_page:t EMP = ' <li class= ' active ' ><a href= '%s?page=%s ' >%s</a></li> '% (self.base_url,i, I,) Els            E:temp = ' <li><a href= '%s?page=%s ' >%s</a></li> '% (self.base_url,i, I,) Page_html_list.append (tEMP) if self.current_page >= self.all_pager:next_page = ' <li><a href= ' # ' > Next &LT;/A&GT;&L T;/li> ' else:next_page = ' <li><a href= '%s?page=%s ' > Next </a></li> '% (Self.bas E_url,self.current_page + 1,) page_html_list.append (next_page) last_page = ' <li><a href= '%s?page=%s "> Last </a></li> '% (Self.base_url,self.all_pager,) page_html_list.append (last_page) return '. J Oin (Page_html_list)

The page_html () function in the above class returns the string containing the Li tag in the page list, and replaces it in the corresponding HTML file in the following way:

function to get the string:

The string is converted into HTML:

Second, Session Introduction

1. Cookie and Session comparison

(a) A cookie is a key-value pair stored on the browser side, while the session is a key-value pair on the server side of the save, but relies on cookies.

(b) In the case of login, the cookie is a key-value pair set in clear text after successful login, and the key-value pair is sent to the client, the plaintext information may be leaking and unsafe; The session generates a random string, which is sent to the user and written to the browser's cookie, and the server also saves one copy.

(c) At the time of login verification, the cookie: determines the key value of the cookie that accompanies the request when the browser sends it, and if so, validates the pass; session: Gets a random string in the cookie of the requesting user, Validates the corresponding value in the session based on a random string

2, session of the classification

As above, according to the session in the server to save the location of the following 5 kinds:

(1) Database session

As the name implies, the session value is stored in the database, Django default support session, and the default is to store session data in the database, namely: Django_session table. Before using this type of session, you need to create a table for the session by executing the following two commands. As follows:

Python manage.py Makemigrationspython manage.py Migrate

The basic file configuration for this type of session is as follows, in the configuration settings in the setting.py file:

    Session_engine = ' django.contrib.sessions.backends.db '   # engine (default)        session_cookie_name = "SessionID"                       # Session cookie saved on browser key, i.e.: sessionid= random string (default)    Session_cookie_path = "/"                               # SESSION Cookie saved Path (default)    Session_cookie_domain = None                             # SESSION COOKIE saved domain name (default)    session_cookie_secure = False                            # Whether the HTTPS transport cookie (default)    session_cookie_httponly = True                           # If the SESSION's cookie only supports HTTP transport (default)    Session_cookie_ Age = 1209600                             # SESSION Cookie Expiration date (2 weeks) (default)    session_expire_at_browser_close = False                  # Whether to close the browser so that the session expires (default)    session_save_every_request = False                       # Whether each request is saved session, the default is not saved after the change (default)

The session is used as follows:

Set up:

Get:

Delete:

 def index (request): # GET, set, delete data in session request.session[' K1 '] request.session.get (' K1 ', None)         request.session[' k1 ' = 123 request.session.setdefault (' K1 ', 123) # exists then does not set del request.session[' K1 '] # All keys, values, key-value pairs Request.session.keys () request.session.values () Request.session.items () requ        Est.session.iterkeys () request.session.itervalues () Request.session.iteritems () # Random string for user session Request.session.session_key # Delete all data with session expiration date less than current date request.session.clear_expired () # Check Whether the random string of the user session is Request.session.exists ("Session_key") in the database # deletes all session data for the current user request.session.d            Elete ("Session_key") Request.session.set_expiry (value) * If value is an integer, the session will expire after a few seconds.            * If value is a datatime or timedelta,session, it will expire after this time.            * If value is 0, the user closes the browser session will expire. * If value is none,session, it will depend on the global session expiration policy. 

(2) Cache session

Use the same way, its configuration file content is as follows:

Configure settings.py     session_engine = ' Django.contrib.sessions.backends.cache '  # engine    Session_cache_alias = '                            the cache alias (default memory cache, or memcache) used by the alias, where the aliases depend on the cache settings      session_cookie_name = "SessionID"                        # The session's cookie is stored on the browser when the key, namely: Sessionid= random string    Session_cookie_path = "/"                                # SESSION of the cookie saved path    session_ Cookie_domain = None                              # SESSION cookie saved domain name    session_cookie_secure = False                             # Whether HTTPS transport cookie    Session_cookie_httponly = True                            # Whether the SESSION's COOKIE only supports HTTP transport    session_cookie_age = 1209600                              # Session cookie Expiration Date (2 weeks)    session_expire_at_browser_close = False                   # whether to close the browser so that the session expires    Session_save_ Every_request = False                        # If the session is saved every time the request is changed, it is saved after the default modification

(3) File session

(4) cache + Database session

(5) Encryption Cookie session

Python Day71 Django Pagination and session Introduction