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Session.php
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1 <?PHP
2
3 #
4 # Axis--Session.php
5 # An Object for Maintaining the Values of Variables Across Pages
6 #
7 # Copyright 1999-2003 Axis Data
8 # This code is free software that can be used or redistributed under the
9 # terms of Version 2 of the GNU General Public License, as published by the
10 # Free Software Foundation (http://www.fsf.org).
11 #
12 # Author: Edward Almasy (almasy@axisdata.com)
13 #
14 # Part of the AxisPHP library v1.2.5
15 # For more information see http://www.axisdata.com/AxisPHP/
16 #
17
18
19 class Session {
20
21 # ---- PUBLIC INTERFACE --------------------------------------------------
22
23 function __construct(&$DB = NULL)
24 {
25 global $APSession_Shutdown_Sessions;
26
27 # create database object if none supplied
28 if ($DB === NULL)
29 {
30 $DB = new Database();
31 }
32
33 # save database object (if supplied) or create new one
34 $this->DB =& $DB;
35
36 # construct session variable name
37 $SessionVar = "APSessionId".md5($DB->DBHostName().$DB->DBName());
38
39 # if session ID available
40 if (isset($_SESSION[$SessionVar]))
41 {
42 # look for session ID in database
43 $this->SessionId = $_SESSION[$SessionVar];
44 $DB->Query("SELECT * FROM APSessions WHERE SessionId = "
45 .intval($this->SessionId));
46
47 # if matching session ID record not found in database
48 if ($DB->NumRowsSelected() < 1)
49 {
50 # clear session ID
51 unset($this->SessionId);
52 }
53 }
54
55 # if session ID found
56 if (isset($this->SessionId))
57 {
58 # load session variables from database
59 $DB->Query("SELECT * FROM APSessionData WHERE SessionId = "
60 .intval($this->SessionId));
61 while ($Record = $DB->FetchRow())
62 {
63 $VarName = $Record["DataName"];
64 $VarValue = unserialize($Record["DataValue"]);
65 if (substr($VarName, -2) == "-T")
66 {
67 $VarName = substr($VarName, 0, -2);
68 $this->SaveVarFlags[$VarName] = FALSE;
69 }
70 else
71 {
72 $this->SaveVarFlags[$VarName] = TRUE;
73 $this->TempVarFlags[$VarName] = FALSE;
74 }
75 $this->SessionVariables[$VarName] = $VarValue;
76 $GLOBALS[$VarName] = $VarValue;
77 }
78 }
79 else
80 {
81 # generate unique session ID
82 do
83 {
84 $this->SessionId = mt_rand();
85 } while ($DB->Query("SELECT COUNT(*) AS FoundCount FROM APSessionData"
86 ." WHERE SessionId = ".$this->SessionId, "FoundCount"));
87
88 # save session ID
89 $_SESSION[$SessionVar] = $this->SessionId;
90 }
91
92 # make sure session state will be saved when page ends
93 $APSession_Shutdown_Sessions[] =& $this;
94 }
95
96 function RegisterVariable($VariableName, $Value = NULL)
97 {
98 # add variable to list of variables to be saved
99 if ($Value !== NULL)
100 {
101 $this->SessionVariables[$VariableName] = $Value;
102 }
103 else
104 {
105 $this->SessionVariables[$VariableName] = $GLOBALS[$VariableName];
106 }
107 $this->SaveVarFlags[$VariableName] = TRUE;
108 $this->TempVarFlags[$VariableName] = FALSE;
109 }
110
111 function PassVariable($VariableName, $Value = NULL)
112 {
113 # add variable to list of variables to be saved
114 if ($Value !== NULL)
115 {
116 $this->SessionVariables[$VariableName] = $Value;
117 }
118 else
119 {
120 if (isset($GLOBALS[$VariableName]))
121 {
122 $this->SessionVariables[$VariableName] = $GLOBALS[$VariableName];
123 }
124 else
125 {
126 $this->SessionVariables[$VariableName] = NULL;
127 }
128 }
129 $this->SaveVarFlags[$VariableName] = TRUE;
130 $this->TempVarFlags[$VariableName] = TRUE;
131 }
132
133 function UnregisterVariable($VariableName)
134 {
135 # remove variable from list of variables to be saved (if present)
136 if (isset($this->SessionVariables[$VariableName]))
137 {
138 unset($this->SessionVariables[$VariableName]);
139 unset($this->TempVarFlags[$VariableName]);
140 }
141 }
142
143 function IsRegistered($VariableName)
144 {
145 return (isset($this->SessionVariables[$VariableName]) ? TRUE : FALSE);
146 }
147
148 function IsPassed($VariableName)
149 {
150 return ((isset($this->SessionVariables[$VariableName]) && $this->TempVarFlags[$VariableName])
151 ? TRUE : FALSE);
152 }
153
154 # retrieve variable with specified name
155 function Get($VariableName)
156 {
157 if (isset($this->SessionVariables[$VariableName]))
158 {
159 return $this->SessionVariables[$VariableName];
160 }
161 else
162 {
163 return NULL;
164 }
165 }
166
167 # retrieve variable with specified name from all active sessions
168 function GetFromAllSessions($VariableName)
169 {
170 # clear out any expired sessions
171 $this->DeleteExpiredSessions();
172
173 # start with empty array
174 $ReturnValue = array();
175
176 # for each instance of variable in session database
177 $DB =& $this->DB;
178 $DB->Query("SELECT SessionId,DataValue FROM APSessionData WHERE DataName = '".$VariableName."'");
179 while ($Record = $DB->FetchRow())
180 {
181 # unpack variable value and add to array to be returned
182 $ReturnValue[$Record["SessionId"]] = unserialize($Record["DataValue"]);
183 }
184
185 # return array of variable values to caller
186 return $ReturnValue;
187 }
188
189
190 # ---- PRIVATE INTERFACE -------------------------------------------------
191
192 # handle to SQL database we use to store session information
193 var $DB;
194
195 # session ID
196 var $SessionId;
197
198 # array containing variables to be maintained between pages
199 var $SessionVariables;
200
201 # flags indicating whether to save variable for next session
202 var $SaveVarFlags;
203
204 # flags indicating whether to mark variable as temporary for next session
205 var $TempVarFlags;
206
207 # how long before sessions will expire (in minutes)
208 var $SessionExpirationTime = 180;
209
210 function SaveState()
211 {
212 # if session record not found in database
213 $this->DB->Query("SELECT * FROM APSessions WHERE SessionId = "
214 .intval($this->SessionId));
215 if ($this->DB->NumRowsSelected() < 1)
216 {
217 # create new session record
218 $this->DB->Query(sprintf("INSERT INTO APSessions "
219 ."(SessionId, LastActiveDate) VALUES "
220 ."(%d, NOW())",
221 $this->SessionId));
222 }
223 else
224 {
225 # update last active timestamp for session
226 $this->DB->query("UPDATE APSessions "
227 ."SET LastActiveDate=NOW() "
228 ."WHERE SessionId = ".intval($this->SessionId));
229 }
230
231 # clear all old stored session variables from database
232 $this->DB->Query(sprintf("DELETE FROM APSessionData WHERE SessionId = '%d'",
233 $this->SessionId));
234
235 # save session variables to database (if any)
236 if (isset($this->SessionVariables))
237 {
238 foreach ($this->SessionVariables as $VariableName => $VariableValue)
239 {
240 if ($this->SaveVarFlags[$VariableName])
241 {
242 if ($this->TempVarFlags[$VariableName]) { $VariableName .= "-T"; }
243 $this->DB->Query(sprintf("INSERT INTO APSessionData "
244 ."(SessionId, DataName, DataValue) VALUES "
245 ."(%d, '%s', '%s')",
246 $this->SessionId,
247 $VariableName,
248 addslashes(serialize($VariableValue))));
249 }
250 }
251 }
252
253 # clear any expired sessions from database
254 $this->DeleteExpiredSessions();
255 }
256
257 function DeleteExpiredSessions()
258 {
259 # retrieve expired session records
260 $DB =& $this->DB;
261 $DB->Query(sprintf("SELECT * FROM APSessions WHERE DATE_SUB(NOW(), INTERVAL %d MINUTE) > LastActiveDate",
262 $this->SessionExpirationTime));
263
264 # if expired sessions were found
265 if ($DB->NumRowsSelected() > 0)
266 {
267 # for each record
268 while ($Record = $DB->FetchRow())
269 {
270 # save record ID
271 $Id[$Record["SessionId"]] = 1;
272 }
273
274 # for each saved session record ID
275 while (list($SessionId) = each($Id))
276 {
277 # delete any stored session data
278 $DB->Query(sprintf("DELETE FROM APSessionData WHERE SessionId=%d",
279 $SessionId));
280 }
281
282 # delete expired session records
283 $DB->Query(sprintf("DELETE FROM APSessions WHERE DATE_SUB(NOW(), INTERVAL %d MINUTE) > LastActiveDate",
284 $this->SessionExpirationTime));
285 }
286 }
287 };
288
289 function APSession_Shutdown()
290 {
291 global $APSession_Shutdown_Sessions;
292
293 # if we have Sessions to shut down
294 if (isset($APSession_Shutdown_Sessions))
295 {
296 # call shutdown functions
297 while (list($Key) = each($APSession_Shutdown_Sessions))
298 {
299 $SessionObject =& $APSession_Shutdown_Sessions[$Key];
300 $SessionObject->SaveState();
301 }
302 }
303 }
304
305 register_shutdown_function("APSession_Shutdown");
306
307
308 ?>
Session\$TempVarFlags
$TempVarFlags
Definition: Session.php:205
Session\Get
Get($VariableName)
Definition: Session.php:155
Database
SQL database abstraction object with smart query caching.
Definition: Database.php:22
Session\$SessionId
$SessionId
Definition: Session.php:196
Session\GetFromAllSessions
GetFromAllSessions($VariableName)
Definition: Session.php:168
Session\DeleteExpiredSessions
DeleteExpiredSessions()
Definition: Session.php:257
Session\$SessionExpirationTime
$SessionExpirationTime
Definition: Session.php:208
Session\IsPassed
IsPassed($VariableName)
Definition: Session.php:148
Session\UnregisterVariable
UnregisterVariable($VariableName)
Definition: Session.php:133
Session\$SaveVarFlags
$SaveVarFlags
Definition: Session.php:202
PHP
PHP
Definition: RSSClient--Test.php:12
Session\$DB
$DB
Definition: Session.php:193
Session\PassVariable
PassVariable($VariableName, $Value=NULL)
Definition: Session.php:111
Session\$SessionVariables
$SessionVariables
Definition: Session.php:199
Session
Definition: Session.php:19
Session\SaveState
SaveState()
Definition: Session.php:210
APSession_Shutdown
APSession_Shutdown()
Definition: Session.php:289
Session\RegisterVariable
RegisterVariable($VariableName, $Value=NULL)
Definition: Session.php:96
Session\__construct
__construct(&$DB=NULL)
Definition: Session.php:23
Session\IsRegistered
IsRegistered($VariableName)
Definition: Session.php:143