发生故障时更改 MySQL 连接 - PHP

Question

我正在做一个项目，我需要测试远程 MySQL 连接，如果它失败，那么我需要代码切换到使用本地 MySQL 连接。我遇到的问题是代码总是显示错误，这真的会扼杀最终用户体验。

我尝试过的事情：

1. 尝试捕获异常
2. 用@ 抑制错误
3. 对着电脑大喊

代码：

//-----Remote MySQL Server-----------
$rem_host="99.99.999.999"; //Host Name 
$rem_user="testUser"; //MySQL Username 
$rem_pass="testPass"; //MySQL Password 
$rem_db="testDb"; //Database Name 


//----Local MySQL Server-----------
$local_host="127.0.0.1"; //Host Name 
$local_user="testLocal"; //MySQL Username 
$local_pass="passLocal"; //MySQL Password 
$local_db="localDb"; //Database Name 


$remoteConnection = mysqli_connect("$rem_host","$rem_user","$rem_pass","$rem_db");

if(!$remoteConnection){ $check_connection=0; }
else{ $check_connection=1; mysqli_close($remoteConnection); }


if($check_connection==1){

$db_host = $rem_host; //Host Name 
$db_user = $rem_user; //MySQL Username 
$db_pass = $rem_pass; //MySQL Password 
$db_name = $rem_db; //Database Name 

}
else{

$db_host = $local_host; //Host Name 
$db_user = $local_user; //MySQL Username 
$db_pass = $local_pass; //MySQL Password 
$db_name = $local_db; //Database Name 

}

?>

Answer 1

根据您的选择更改第 2 行。首先我获取 URL，然后检查它是否有“localhost”字样，然后我按照 localhost 详细信息（我在本地机器中使用 localhost/）。如果 $actual_link 无法获取 localhost 则关注在线详情

<?php
$actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
if (strpos($actual_link,'localhost') !== false) 
{
    //local db detail
    $servername='localhost';     
    $dbusername='root';          
    $dbpassword='';              
    $dbname='db_gbook';
    echo "local";
}
else
{
    //online db detail
    $servername='localhost';     
    $dbusername='dbaname';          
    $dbpassword='dbpassword';              
    $dbname='yourdbname';
    echo "web";
}

global $link;
$link=mysql_connect ("$servername","$dbusername","$dbpassword");
if(!$link)
{
    die("Could not connect to MySQL");
}
mysql_select_db("$dbname",$link) or die ("could not open db".mysql_error());    
echo "Succesive";
?>