Question

I am having this problem getting a variable by its name. What I am doing is including a path with connections and I want the connections are named in a certain way. I want to iterate through those conenctions and add them to a queue but the problem is, I cannot use ‘.’ to concat a variable.

Code looks like this. Config File:

//Set the host the databse will connect too
    $config_db_hostname='xxx.xxx.xxx';
    //Set the user who is connecting to the database
    $config_db_user='a user';
    //Set the password for user who is connecting to the database
    $config_db_pass='abc123';
    //Set the database type
    $config_db_type='mysql';
    //Set the name of the database
    $config_db_name='phonephare_development';
    //Optional: Set the schema, if any
    $config_db_schema='';
    //Optional: Set the port, otherwise default port will be used
    $config_db_port='';
    //Set the prefix for the table names
    $config_db_prefix='pf_';

    //Set the host the databse will connect too
    $config_db_hostname_1='localhost';
    //Set the user who is connecting to the database
    $config_db_user_1='test';
    //Set the password for user who is connecting to the database
    $config_db_pass_1='test';
    //Set the database type
    $config_db_type_1='mysql';
    //Set the name of the database
    $config_db_name_1='test_development';
    //Optional: Set the schema, if any
    $config_db_schema_1='';
    //Optional: Set the port, otherwise default port will be used
    $config_db_port_1='';
    //Set the prefix for the table names
    $config_db_prefix_1='pv_';

Function for getting values:

public static function init(){
        if(file_exists(PV_DB_CONFIG)){
            include(PV_DB_CONFIG);


            for ($i = 0; $i <= 3; $i++) {
                if($i){
                    $profile_id='_'.$i;
                } else {
                    $profile_id='';
                }
                // Database variables
                self::$connections['connection'.$profile_id]['dbhost'] = ($config_db_hostname.$profile_id);
                self::$connections['connection'.$profile_id]['dbuser'] = $config_db_user.$profile_id;
                self::$connections['connection'.$profile_id]['dbpass'] = $config_db_pass.$profile_id;
                self::$connections['connection'.$profile_id]['dbtype'] = $config_db_type.$profile_id;
                self::$connections['connection'.$profile_id]['dbname'] = $config_db_name.$profile_id;
                self::$connections['connection'.$profile_id]['dbport'] = $config_db_port.$profile_id;
                self::$connections['connection_'.$profile_id]['dbschema'] = $config_db_schema.$profile_id;
                self::$connections['connection_'.$profile_id]['dbprefix'] = $config_db_prefix.$profile_id;
            }

        }

}//end init

So how can I dynamically read this variables?

Answer 1

You can read ‘dynamic’ variables like this:

$varname = 'config_db_user';
if ($i)
  $varname .= '_' . $i;

$varvalue = $$varname; // $varvalue contains the value now.

But this will make your code really hard to read and hard to maintain. Rather make your config like this:

$profiles[1]['config_db_user'] = 'whatever';

Then, you can just read $profiles[$profile_id]['configfield] to get what you want. There are probably other ways that may even be better, but stop putting together dynamic variable names, because that’s the worst of all.