Hệ thống quản lý phòng khám trực tuyến bằng PHP

ajax_check_unique.php
project /

1 <?php
2     /**
3      * Checks if the value of a specific unique field already exists
4      * @param t table name
5      * @param f field name
6      * @param id the value of the PK of the record if it already exists
7      * @param value the value to be checked for being a duplicate
8      * @returns json result: { "result": "ok" } or { "result": "error" }
9      */
10     $currDir=dirname(__FILE__);
11     include("$currDir/defaultLang.php");
12     include("$currDir/language.php");
13     include("$currDir/lib.php");
14
15     /* maintenance mode */
16     handle_maintenance();
17
18     /* return json */
19     header('Content-type: application/json');
20
21     $error_return = '{ "result": "error" }';
22     $ok_return = '{ "result": "ok" }';
23
24     /* capture inputs */
25     $table = new Request('t');
26     $field = new Request('f');
27     $id = new Request('id');
28     $value = new Request('value');
29
30     /* prevent conventional error output via a shutdown handler */
31     function cancel_all_buffers(){
32         while(ob_get_level()) ob_end_clean();
33         echo $GLOBALS['result'];
34     }
35     $GLOBALS['result'] = $error_return; // error message to return if any error occurs
36     ob_start();
37     register_shutdown_function('cancel_all_buffers');
38
39     /* user has access to table? */
40     $table_accessible = get_sql_from($table->raw);
41     if(!$table_accessible) exit();
42
43     /* PK field name */
44     $pk = getPKFieldName($table->raw);
45     if(!$pk) exit();
46     $spk = makeSafe($pk, false);
47
48     /* check if value exists in records other than the current record */
49     $where = "`{$field->sql}`='{$value->sql}'";
50     if($id->raw){ // existing record to be excluded from search
51         $where .= " and `{$spk}`!='{$id->sql}'";
52     }
53     $chk_query = "select count(1) from `{$table->sql}` where {$where}";
54     $exists = sqlValue($chk_query);
55
56     /* return error if exists or a query error took place */
57     if($exists !== 0 && $exists !== '0') exit();
58
59     /* return ok if unique */
60     $GLOBALS['result'] = $ok_return;