Nothing 2007-7-18 09:30
用数据库管理PHP会话
[color=#000000][color=#0000cc]<[/color][color=#0000cc]?[/color][color=#0000ff]php[/color]
[color=#ff9900]/*
// =======================================
用数据库来管理会话的最大动机:
通过部署多个Web服务器，可以平衡HTTP负载并利用数据库服务器，也可以解决服务器的性能瓶颈问题。
// =======================================
*/[/color]
[color=#ff9900]/*
// 会话表结构
// 有一个附加的索引，它允许使用后面描述的自定义垃圾收集代码快速删除未使用的会话。
create talbe phpsession(
session_id varchar(50) not null,
session_variable text,
last_accessed decimal(15,3) not null,
primary key(session_id),
key last_acc (last_acessed)
)
*/[/color]
[color=#0000ff]function[/color] getMicroTime[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#ff9900]// microtime()返回自格林威治时间
[/color]
[color=#ff9900]// 1970年1月1日0:00:00起计算的秒数
[/color]
[color=#ff9900]// 作为微秒部分和一个秒部分
[/color]
[color=#ff9900]// 例如: 0.08344800 100952237
[/color]
[color=#ff9900]// 将这两部分转换到一个数组中
[/color]
[color=#0000ff]$[/color][color=#008080]mtime[/color] [color=#0000cc]=[/color] [color=#ff0000]explode[/color][color=#0000cc]([/color][color=#ff00ff]" "[/color][color=#0000cc],[/color] [color=#ff0000]microtime[/color][color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#ff9900]// 返回这两部分之和
[/color]
[color=#ff9900]// 例如: 100952237.08344800
[/color]
[color=#0000ff]return[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]mtime[/color][color=#0000cc][[/color]1[color=#0000cc]][/color][color=#0000cc]+[/color][color=#0000ff]$[/color][color=#008080]mtime[/color][color=#0000cc][[/color]0[color=#0000cc]][/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#ff9900]/*
// 每当初试化一个会话时由PHP调用会话打开处理器
// 总是返回true
*/[/color]
[color=#0000ff]function[/color] sessionOpen[color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]database_name[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]table_name[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#ff9900]// 数据库连接
[/color]
[color=#ff9900]// $connection
[/color]
[color=#ff9900]// 保存表名称的全局变量
[/color]
[color=#ff9900]// $session_table
[/color]
[color=#ff9900]// 将数据库名保存在一个全局变量中
[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc];[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]hostname[/color][color=#0000cc];[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]username[/color][color=#0000cc];[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]password[/color][color=#0000cc];[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]connection[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_connect[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]hostname[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]username[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]password[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#ff0000]mysql_select_db[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]database_name[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#ff9900]// 将表名保存在一个全局变量中
[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]session_table[/color][color=#0000cc];[/color]
[color=#0000ff]$[/color][color=#008080]session_table[/color] [color=#0000cc]=[/color] [color=#0000ff]$[/color][color=#008080]table_name[/color][color=#0000cc];[/color]
[color=#0000ff]return[/color] [color=#0000ff]true[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#ff9900]/*
// 每当调用session_start()和读会话变量时
// 调用该函数
// 当会话不存在时返回""
// 当会话存在时返回(串行化的)字符串
*/[/color]
[color=#0000ff]function[/color] sessionRead[color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]sess_id[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#ff9900]// 访问DBMS连接
[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc];[/color]
[color=#ff9900]// 访问保存表名称的全局变量
[/color]
[color=#ff9900]// 该表保存会话变量
[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]session_table[/color][color=#0000cc];[/color]
[color=#ff9900]// 组织一个查询以找到由$session_id识别的会话
[/color]
[color=#0000ff]$[/color][color=#008080]search_query[/color] [color=#0000cc]=[/color] [color=#ff00ff]"SELECT * FROM $sesson_table WHERE session_id= '$sess_id'"[/color][color=#0000cc];[/color]
[color=#ff9900]// 执行查询
[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_query[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]search_query[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#ff0000]mysql_num_rows[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color][color=#0000cc])[/color] [color=#0000cc]=[/color][color=#0000cc]=[/color] 0[color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#ff9900]// 没有找到会话，返回一个空字符串
[/color]
[color=#0000ff]return[/color] [color=#ff00ff]''[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color][color=#0000ff]else[/color][color=#0000cc]{[/color]
[color=#ff9900]// 找到一个会话，返回串行字符串
[/color]
[color=#0000ff]$[/color][color=#008080]row[/color] [color=#0000cc]=[/color] [color=#ff0000]mysql_fetch_array[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000ff]return[/color] [color=#0000ff]$[/color][color=#008080]row[/color][color=#0000cc][[/color][color=#ff00ff]"session_variable"[/color][color=#0000cc]][/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000cc]}[/color]
[color=#ff9900]/*
// 当利用session_start()调用初试化一个会话时，
// 当注册或注销变量时和当修改会话变量时,
// 调用该函数。成功则返回true
*/[/color]
[color=#0000ff]function[/color] sessionWrite[color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]sess_id[/color][color=#0000cc],[/color][color=#0000ff]$[/color][color=#008080]val[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc];[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]session_table[/color][color=#0000cc];[/color]
[color=#0000ff]$[/color][color=#008080]time_stamp[/color] [color=#0000cc]=[/color] getMicroTime[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000ff]$[/color][color=#008080]search_query[/color] [color=#0000cc]=[/color] [color=#ff00ff]"SELECT session_id FROM $session_table
WHERE session_id = '$sess_id'"[/color][color=#0000cc];[/color]
[color=#ff9900]// 执行查询
[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_query[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]search_query[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#ff0000]mysql_num_rows[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color][color=#0000cc])[/color] [color=#0000cc]=[/color][color=#0000cc]=[/color] 0[color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#ff9900]// 没有找到会话，则插入一个新的会话
[/color]
[color=#0000ff]$[/color][color=#008080]insert_query[/color] [color=#0000cc]=[/color]
[color=#ff00ff]"INSERT INTO $session_table
(session_id, session_variable, last_accessed)
VALUES ('$sess_id', '$val', $time_stamp)"[/color][color=#0000cc];[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_query[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]insert_query[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000cc]}[/color][color=#0000ff]else[/color][color=#0000cc]{[/color]
[color=#ff9900]// 找到存在的会话，更新会话变量
[/color]
[color=#0000ff]$[/color][color=#008080]update_query[/color] [color=#0000cc]=[/color] [color=#ff00ff]"
UPDATE $session_table
SET session_variable = '$val',
last_accessed = $time_stamp
WHERE session_id = '$sess_id'"[/color][color=#0000cc];[/color]
[color=#ff9900]//
[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_query[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]update_query[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000cc]}[/color]
[color=#0000ff]return[/color] [color=#0000ff]true[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#ff9900]/*
// 在关闭会话时执行函数
// 总是返回true
*/[/color]
[color=#0000ff]function[/color] sessionClose[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#0000ff]return[/color] [color=#0000ff]true[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#ff9900]/*
// 每当发出session_destroy()函数调用时
// 就会调用该函数。如果会话已经成功地删除则返回true
*/[/color]
[color=#0000ff]function[/color] sessionDestroy[color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]sess_id[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc];[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]session_table[/color][color=#0000cc];[/color]
[color=#0000ff]$[/color][color=#008080]delete_query[/color] [color=#0000cc]=[/color] [color=#ff00ff]"
DELETE FROM $session_table
WHERE session_id = '$sess_id'"[/color][color=#0000cc];[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_query[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]update_query[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000ff]return[/color] [color=#0000ff]true[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#ff9900]/*
// 垃圾收集处理器
// 利用session.gc_probability中指定的可能性
// 在会话开始时调用该函数
// 通过删除所有已经有最后$max_lifetime秒未使用的
// 会话来执行垃圾收集，其中$max_lifetime在
// session.gc_maxlifetime中设置
// 如果DELELTE查询成功则返回true
*/[/color]
[color=#0000ff]function[/color] sessionGC[color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]max_lifetime[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc];[/color]
[color=#0000ff]global[/color] [color=#0000ff]$[/color][color=#008080]session_table[/color][color=#0000cc];[/color]
[color=#0000ff]$[/color][color=#008080]time_stamp[/color] [color=#0000cc]=[/color] getMicroTime[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000ff]$[/color][color=#008080]delete_query[/color] [color=#0000cc]=[/color] [color=#ff00ff]"
DELETE FROM $session_table
WHERE last_accessed < ($time_stamp - $max_lifetime)"[/color][color=#0000cc];[/color]
[color=#0000ff]if[/color][color=#0000cc]([/color][color=#0000cc]![/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]result[/color] [color=#0000cc]=[/color] [color=#0000cc]@[/color][color=#ff0000]mysql_query[/color][color=#0000cc]([/color][color=#0000ff]$[/color][color=#008080]delete_query[/color][color=#0000cc],[/color] [color=#0000ff]$[/color][color=#008080]connection[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc])[/color][color=#0000cc]{[/color]
showerror[color=#0000cc]([/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000ff]return[/color] [color=#0000ff]true[/color][color=#0000cc];[/color]
[color=#0000cc]}[/color]
[color=#0000cc]?[/color][color=#0000cc]>[/color][/color]
[color=#000][font=新宋体]
[/font][/color]
[color=#000][font=新宋体][color=#00cc]利用PHP来注册用户定义的会话处理器
[color=#0000cc]<?[/color][color=#0000ff]php[/color]
[color=#ff9900]// 调用来注册用户回调函数
[/color]
[color=#ff0000]session_set_save_handler[/color][color=#000000] [/color][color=#0000cc]([/color]
[color=#000000] [/color][color=#ff00ff]"sessionOpen"[/color][color=#0000cc],[/color]
[color=#000000] [/color][color=#ff00ff]"sessionClose"[/color][color=#0000cc],[/color]
[color=#000000] [/color][color=#ff00ff]"sessionRead"[/color][color=#0000cc],[/color]
[color=#000000] [/color][color=#ff00ff]"sessionWrite"[/color][color=#0000cc],[/color]
[color=#000000] [/color][color=#ff00ff]"sessionDestroy"[/color][color=#0000cc],[/color]
[color=#000000] [/color][color=#ff00ff]"sessionGC"[/color][color=#0000cc])[/color][color=#0000cc];[/color]
[color=#0000cc]?[/color][color=#0000cc]>[/color]
[/color][/font][/color]