1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
|
<?php
/**
* Elgg database procedural code.
*
* Includes functions for establishing and retrieving a database link,
* reading data, writing data, upgrading DB schemas, and sanitizing input.
*
* @package Elgg.Core
* @subpackage Database
*/
/**
* Query cache for all queries.
*
* Each query and its results are stored in this array as:
* <code>
* $DB_QUERY_CACHE[$query] => array(result1, result2, ... resultN)
* </code>
*
* @warning be array this var may be an array or ElggStaticVariableCache depending on when called :(
*
* @global ElggStaticVariableCache|array $DB_QUERY_CACHE
* @access private
*/
global $DB_QUERY_CACHE;
$DB_QUERY_CACHE = array();
/**
* Queries to be executed upon shutdown.
*
* These queries are saved to an array and executed using
* a function registered by register_shutdown_function().
*
* Queries are saved as an array in the format:
* <code>
* $DB_DELAYED_QUERIES[] = array(
* 'q' => str $query,
* 'l' => resource $dblink,
* 'h' => str $handler // a callback function
* );
* </code>
*
* @global array $DB_DELAYED_QUERIES
* @access private
*/
global $DB_DELAYED_QUERIES;
$DB_DELAYED_QUERIES = array();
/**
* Database connection resources.
*
* Each database link created with establish_db_link($name) is stored in
* $dblink as $dblink[$name] => resource. Use get_db_link($name) to retrieve it.
*
* @global resource[] $dblink
* @access private
*/
global $dblink;
$dblink = array();
/**
* Database call count
*
* Each call to the database increments this counter.
*
* @global integer $dbcalls
* @access private
*/
global $dbcalls;
$dbcalls = 0;
/**
* Establish a connection to the database servser
*
* Connect to the database server and use the Elgg database for a particular database link
*
* @param string $dblinkname The type of database connection. Used to identify the
* resource. eg "read", "write", or "readwrite".
*
* @return void
* @throws DatabaseException
* @access private
*/
function establish_db_link($dblinkname = "readwrite") {
// Get configuration, and globalise database link
global $CONFIG, $dblink, $DB_QUERY_CACHE;
if ($dblinkname != "readwrite" && isset($CONFIG->db[$dblinkname])) {
if (is_array($CONFIG->db[$dblinkname])) {
$index = rand(0, sizeof($CONFIG->db[$dblinkname]));
$dbhost = $CONFIG->db[$dblinkname][$index]->dbhost;
$dbuser = $CONFIG->db[$dblinkname][$index]->dbuser;
$dbpass = $CONFIG->db[$dblinkname][$index]->dbpass;
$dbname = $CONFIG->db[$dblinkname][$index]->dbname;
} else {
$dbhost = $CONFIG->db[$dblinkname]->dbhost;
$dbuser = $CONFIG->db[$dblinkname]->dbuser;
$dbpass = $CONFIG->db[$dblinkname]->dbpass;
$dbname = $CONFIG->db[$dblinkname]->dbname;
}
} else {
$dbhost = $CONFIG->dbhost;
$dbuser = $CONFIG->dbuser;
$dbpass = $CONFIG->dbpass;
$dbname = $CONFIG->dbname;
}
// Connect to database
if (!$dblink[$dblinkname] = mysql_connect($dbhost, $dbuser, $dbpass, true)) {
$msg = elgg_echo('DatabaseException:WrongCredentials',
array($dbuser, $dbhost, "****"));
throw new DatabaseException($msg);
}
if (!mysql_select_db($dbname, $dblink[$dblinkname])) {
$msg = elgg_echo('DatabaseException:NoConnect', array($dbname));
throw new DatabaseException($msg);
}
// Set DB for UTF8
mysql_query("SET NAMES utf8");
$db_cache_off = FALSE;
if (isset($CONFIG->db_disable_query_cache)) {
$db_cache_off = $CONFIG->db_disable_query_cache;
}
// Set up cache if global not initialized and query cache not turned off
if ((!$DB_QUERY_CACHE) && (!$db_cache_off)) {
// @todo everywhere else this is assigned to array(), making it dangerous to call
// object methods on this. We should consider making this an plain array
$DB_QUERY_CACHE = new ElggStaticVariableCache('db_query_cache');
}
}
/**
* Establish database connections
*
* If the configuration has been set up for multiple read/write databases, set those
* links up separately; otherwise just create the one database link.
*
* @return void
* @access private
*/
function setup_db_connections() {
global $CONFIG;
if (!empty($CONFIG->db->split)) {
establish_db_link('read');
establish_db_link('write');
} else {
establish_db_link('readwrite');
}
}
/**
* Display profiling information about db at NOTICE debug level upon shutdown.
*
* @return void
* @access private
*/
function db_profiling_shutdown_hook() {
global $dbcalls;
// demoted to NOTICE as it corrupts javasript at DEBUG
elgg_log("DB Queries for this page: $dbcalls", 'NOTICE');
}
/**
* Execute any delayed queries upon shutdown.
*
* @return void
* @access private
*/
function db_delayedexecution_shutdown_hook() {
global $DB_DELAYED_QUERIES;
foreach ($DB_DELAYED_QUERIES as $query_details) {
try {
$link = $query_details['l'];
if ($link == 'read' || $link == 'write') {
$link = get_db_link($link);
} elseif (!is_resource($link)) {
elgg_log("Link for delayed query not valid resource or db_link type. Query: {$query_details['q']}", 'WARNING');
}
$result = execute_query($query_details['q'], $link);
if ((isset($query_details['h'])) && (is_callable($query_details['h']))) {
$query_details['h']($result);
}
} catch (Exception $e) {
// Suppress all errors since these can't be dealt with here
elgg_log($e, 'WARNING');
}
}
}
/**
* Returns (if required, also creates) a database link resource.
*
* Database link resources are stored in the {@link $dblink} global. These
* resources are created by {@link setup_db_connections()}, which is called if
* no links exist.
*
* @param string $dblinktype The type of link we want: "read", "write" or "readwrite".
*
* @return resource Database link
* @access private
*/
function get_db_link($dblinktype) {
global $dblink;
if (isset($dblink[$dblinktype])) {
return $dblink[$dblinktype];
} else if (isset($dblink['readwrite'])) {
return $dblink['readwrite'];
} else {
setup_db_connections();
return get_db_link($dblinktype);
}
}
/**
* Execute an EXPLAIN for $query.
*
* @param string $query The query to explain
* @param mixed $link The database link resource to user.
*
* @return mixed An object of the query's result, or FALSE
* @access private
*/
function explain_query($query, $link) {
if ($result = execute_query("explain " . $query, $link)) {
return mysql_fetch_object($result);
}
return FALSE;
}
/**
* Execute a query.
*
* $query is executed via {@link mysql_query()}. If there is an SQL error,
* a {@link DatabaseException} is thrown.
*
* @internal
* {@link $dbcalls} is incremented and the query is saved into the {@link $DB_QUERY_CACHE}.
*
* @param string $query The query
* @param resource $dblink The DB link
*
* @return resource result of mysql_query()
* @throws DatabaseException
* @access private
*/
function execute_query($query, $dblink) {
global $dbcalls;
if ($query == NULL) {
throw new DatabaseException(elgg_echo('DatabaseException:InvalidQuery'));
}
if (!is_resource($dblink)) {
throw new DatabaseException(elgg_echo('DatabaseException:InvalidDBLink'));
}
$dbcalls++;
$result = mysql_query($query, $dblink);
if (mysql_errno($dblink)) {
throw new DatabaseException(mysql_error($dblink) . "\n\n QUERY: " . $query);
}
return $result;
}
/**
* Queue a query for execution upon shutdown.
*
* You can specify a handler function if you care about the result. This function will accept
* the raw result from {@link mysql_query()}.
*
* @param string $query The query to execute
* @param resource|string $dblink The database link to use or the link type (read | write)
* @param string $handler A callback function to pass the results array to
*
* @return true
* @access private
*/
function execute_delayed_query($query, $dblink, $handler = "") {
global $DB_DELAYED_QUERIES;
if (!isset($DB_DELAYED_QUERIES)) {
$DB_DELAYED_QUERIES = array();
}
if (!is_resource($dblink) && $dblink != 'read' && $dblink != 'write') {
return false;
}
// Construct delayed query
$delayed_query = array();
$delayed_query['q'] = $query;
$delayed_query['l'] = $dblink;
$delayed_query['h'] = $handler;
$DB_DELAYED_QUERIES[] = $delayed_query;
return TRUE;
}
/**
* Write wrapper for execute_delayed_query()
*
* @param string $query The query to execute
* @param string $handler The handler if you care about the result.
*
* @return true
* @uses execute_delayed_query()
* @uses get_db_link()
* @access private
*/
function execute_delayed_write_query($query, $handler = "") {
return execute_delayed_query($query, 'write', $handler);
}
/**
* Read wrapper for execute_delayed_query()
*
* @param string $query The query to execute
* @param string $handler The handler if you care about the result.
*
* @return true
* @uses execute_delayed_query()
* @uses get_db_link()
* @access private
*/
function execute_delayed_read_query($query, $handler = "") {
return execute_delayed_query($query, 'read', $handler);
}
/**
* Retrieve rows from the database.
*
* Queries are executed with {@link execute_query()} and results
* are retrieved with {@link mysql_fetch_object()}. If a callback
* function $callback is defined, each row will be passed as the single
* argument to $callback. If no callback function is defined, the
* entire result set is returned as an array.
*
* @param mixed $query The query being passed.
* @param string $callback Optionally, the name of a function to call back to on each row
*
* @return array An array of database result objects or callback function results. If the query
* returned nothing, an empty array.
* @access private
*/
function get_data($query, $callback = "") {
return elgg_query_runner($query, $callback, false);
}
/**
* Retrieve a single row from the database.
*
* Similar to {@link get_data()} but returns only the first row
* matched. If a callback function $callback is specified, the row will be passed
* as the only argument to $callback.
*
* @param mixed $query The query to execute.
* @param string $callback A callback function
*
* @return mixed A single database result object or the result of the callback function.
* @access private
*/
function get_data_row($query, $callback = "") {
return elgg_query_runner($query, $callback, true);
}
/**
* Handles returning data from a query, running it through a callback function,
* and caching the results. This is for R queries (from CRUD).
*
* @access private
*
* @param string $query The query to execute
* @param string $callback An optional callback function to run on each row
* @param bool $single Return only a single result?
*
* @return array An array of database result objects or callback function results. If the query
* returned nothing, an empty array.
* @since 1.8.0
* @access private
*/
function elgg_query_runner($query, $callback = null, $single = false) {
global $DB_QUERY_CACHE;
// Since we want to cache results of running the callback, we need to
// need to namespace the query with the callback and single result request.
// http://trac.elgg.org/ticket/4049
$hash = (string)$callback . (int)$single . $query;
// Is cached?
if ($DB_QUERY_CACHE) {
$cached_query = $DB_QUERY_CACHE[$hash];
if ($cached_query !== FALSE) {
elgg_log("DB query $query results returned from cache (hash: $hash)", 'NOTICE');
return $cached_query;
}
}
$dblink = get_db_link('read');
$return = array();
if ($result = execute_query("$query", $dblink)) {
// test for callback once instead of on each iteration.
// @todo check profiling to see if this needs to be broken out into
// explicit cases instead of checking in the iteration.
$is_callable = is_callable($callback);
while ($row = mysql_fetch_object($result)) {
if ($is_callable) {
$row = $callback($row);
}
if ($single) {
$return = $row;
break;
} else {
$return[] = $row;
}
}
}
if (empty($return)) {
elgg_log("DB query $query returned no results.", 'NOTICE');
}
// Cache result
if ($DB_QUERY_CACHE) {
$DB_QUERY_CACHE[$hash] = $return;
elgg_log("DB query $query results cached (hash: $hash)", 'NOTICE');
}
return $return;
}
/**
* Insert a row into the database.
*
* @note Altering the DB invalidates all queries in {@link $DB_QUERY_CACHE}.
*
* @param mixed $query The query to execute.
*
* @return int|false The database id of the inserted row if a AUTO_INCREMENT field is
* defined, 0 if not, and false on failure.
* @access private
*/
function insert_data($query) {
elgg_log("DB query $query", 'NOTICE');
$dblink = get_db_link('write');
_elgg_invalidate_query_cache();
if (execute_query("$query", $dblink)) {
return mysql_insert_id($dblink);
}
return FALSE;
}
/**
* Update a row in the database.
*
* @note Altering the DB invalidates all queries in {@link $DB_QUERY_CACHE}.
*
* @param string $query The query to run.
*
* @return bool
* @access private
*/
function update_data($query) {
elgg_log("DB query $query", 'NOTICE');
$dblink = get_db_link('write');
_elgg_invalidate_query_cache();
if (execute_query("$query", $dblink)) {
return TRUE;
}
return FALSE;
}
/**
* Remove a row from the database.
*
* @note Altering the DB invalidates all queries in {@link $DB_QUERY_CACHE}.
*
* @param string $query The SQL query to run
*
* @return int|false The number of affected rows or false on failure
* @access private
*/
function delete_data($query) {
elgg_log("DB query $query", 'NOTICE');
$dblink = get_db_link('write');
_elgg_invalidate_query_cache();
if (execute_query("$query", $dblink)) {
return mysql_affected_rows($dblink);
}
return FALSE;
}
/**
* Invalidate the query cache
*
* @access private
*/
function _elgg_invalidate_query_cache() {
global $DB_QUERY_CACHE;
if ($DB_QUERY_CACHE) {
/* @var ElggStaticVariableCache $DB_QUERY_CACHE */
$DB_QUERY_CACHE->clear();
elgg_log("Query cache invalidated", 'NOTICE');
}
}
/**
* Return tables matching the database prefix {@link $CONFIG->dbprefix}% in the currently
* selected database.
*
* @return array|false List of tables or false on failure
* @static array $tables Tables found matching the database prefix
* @access private
*/
function get_db_tables() {
global $CONFIG;
static $tables;
if (isset($tables)) {
return $tables;
}
try{
$result = get_data("show tables like '" . $CONFIG->dbprefix . "%'");
} catch (DatabaseException $d) {
// Likely we can't handle an exception here, so just return false.
return FALSE;
}
$tables = array();
if (is_array($result) && !empty($result)) {
foreach ($result as $row) {
$row = (array) $row;
if (is_array($row) && !empty($row)) {
foreach ($row as $element) {
$tables[] = $element;
}
}
}
} else {
return FALSE;
}
return $tables;
}
/**
* Optimise a table.
*
* Executes an OPTIMIZE TABLE query on $table. Useful after large DB changes.
*
* @param string $table The name of the table to optimise
*
* @return bool
* @access private
*/
function optimize_table($table) {
$table = sanitise_string($table);
return update_data("optimize table $table");
}
/**
* Get the last database error for a particular database link
*
* @param resource $dblink The DB link
*
* @return string Database error message
* @access private
*/
function get_db_error($dblink) {
return mysql_error($dblink);
}
/**
* Runs a full database script from disk.
*
* The file specified should be a standard SQL file as created by
* mysqldump or similar. Statements must be terminated with ;
* and a newline character (\n or \r\n) with only one statement per line.
*
* The special string 'prefix_' is replaced with the database prefix
* as defined in {@link $CONFIG->dbprefix}.
*
* @warning Errors do not halt execution of the script. If a line
* generates an error, the error message is saved and the
* next line is executed. After the file is run, any errors
* are displayed as a {@link DatabaseException}
*
* @param string $scriptlocation The full path to the script
*
* @return void
* @throws DatabaseException
* @access private
*/
function run_sql_script($scriptlocation) {
if ($script = file_get_contents($scriptlocation)) {
global $CONFIG;
$errors = array();
// Remove MySQL -- style comments
$script = preg_replace('/\-\-.*\n/', '', $script);
// Statements must end with ; and a newline
$sql_statements = preg_split('/;[\n\r]+/', $script);
foreach ($sql_statements as $statement) {
$statement = trim($statement);
$statement = str_replace("prefix_", $CONFIG->dbprefix, $statement);
if (!empty($statement)) {
try {
update_data($statement);
} catch (DatabaseException $e) {
$errors[] = $e->getMessage();
}
}
}
if (!empty($errors)) {
$errortxt = "";
foreach ($errors as $error) {
$errortxt .= " {$error};";
}
$msg = elgg_echo('DatabaseException:DBSetupIssues') . $errortxt;
throw new DatabaseException($msg);
}
} else {
$msg = elgg_echo('DatabaseException:ScriptNotFound', array($scriptlocation));
throw new DatabaseException($msg);
}
}
/**
* Format a query string for logging
*
* @param string $query Query string
* @return string
* @access private
*/
function elgg_format_query($query) {
// remove newlines and extra spaces so logs are easier to read
return preg_replace('/\s\s+/', ' ', $query);
}
/**
* Sanitise a string for database use, but with the option of escaping extra characters.
*
* @param string $string The string to sanitise
* @param string $extra_escapeable Extra characters to escape with '\\'
*
* @return string The escaped string
*/
function sanitise_string_special($string, $extra_escapeable = '') {
$string = sanitise_string($string);
for ($n = 0; $n < strlen($extra_escapeable); $n++) {
$string = str_replace($extra_escapeable[$n], "\\" . $extra_escapeable[$n], $string);
}
return $string;
}
/**
* Sanitise a string for database use.
*
* @param string $string The string to sanitise
*
* @return string Sanitised string
*/
function sanitise_string($string) {
// @todo does this really need the trim?
// there are times when you might want trailing / preceeding white space.
return mysql_real_escape_string(trim($string));
}
/**
* Wrapper function for alternate English spelling
*
* @param string $string The string to sanitise
*
* @return string Sanitised string
*/
function sanitize_string($string) {
return sanitise_string($string);
}
/**
* Sanitises an integer for database use.
*
* @param int $int Value to be sanitized
* @param bool $signed Whether negative values should be allowed (true)
* @return int
*/
function sanitise_int($int, $signed = true) {
$int = (int) $int;
if ($signed === false) {
if ($int < 0) {
$int = 0;
}
}
return (int) $int;
}
/**
* Sanitizes an integer for database use.
* Wrapper function for alternate English spelling (@see sanitise_int)
*
* @param int $int Value to be sanitized
* @param bool $signed Whether negative values should be allowed (true)
* @return int
*/
function sanitize_int($int, $signed = true) {
return sanitise_int($int, $signed);
}
/**
* Registers shutdown functions for database profiling and delayed queries.
*
* @access private
*/
function init_db() {
register_shutdown_function('db_delayedexecution_shutdown_hook');
register_shutdown_function('db_profiling_shutdown_hook');
}
elgg_register_event_handler('init', 'system', 'init_db');
|