Choices
I am learning OOP PHP, but some things are really confusing. I have a general idea of where to use static methods, but I’m not sure if here it’s a good idea.
My questions is about which is actually the best approach for the specific problem I am facing (described below). The general guidelines I’ve found online didn’t help for this specific problem. Here is what I thought (from more likely to be correct to less):
-
Extend the Language class, create a single object (that gets the language in the initialization) and call a method with the $id that would return the translated string.
-
Merge both classes into one. The language would be found when initialized and a method called when needed. But it would behave a little as a God object.
-
Make the Language class static. Therefore I would be able to use it from within the Text. I would create a Text instance and call a method with different $id. Similar to using it with globals. There’s almost no other place where I’d need to use the Language class.
-
Extend the Language class with Text, create an object for each translation. This would probably create too much overhead.
-
Not do anything. It’s tempting (don’t fix it if it’s not broken), but I intend to start developing with someone else soon, so clean and clear code is needed.
Code
Now the simple class:
class Language
{
public $Lang;
public function __construct()
{
if ( !empty($_POST['lang']) ) // If the user tries to change the language
{
$this->Lang = mysql_real_escape_string($_POST['lang']); // Assign the language to variable.
$_SESSION['lang'] = $this->Lang; //Sets the session to have that language.
if ($_SESSION['logged']==1) // If user is logged
{
$User=$_SESSION['user'];
mysql_query("UPDATE users SET lang='$this->Lang' WHERE email='$User'") or die(mysql_error()); // Saves the language into user preferences
}
}
else // If no request is done.
{
if ($_SESSION['logged']==1) // DO. Check for user's language
{
$User=mysql_real_escape_string($_SESSION['user']);
$result=mysql_query("SELECT * FROM users WHERE email='$User'");
$row=mysql_fetch_array($result);
$this->Lang=$row['lang'];
}
else
if ( !empty ($_SESSION['lang'])) // If the session exists (not empty)
$this->Lang = $_SESSION['lang']; // Assign the session language to variable.
else // If it doesn't exist
$this->Lang = substr ($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2); // Get it from the browser
}
//If the language is not supported (or still doesn't exist), then put "en" as default. Supported so far: en, es.
if ( $this->Lang !== "en" && $this->Lang !== "es") $this->Lang="en";
}
}
I have few methods inside this class, but that’s the only relevan code here. So I initialize it with $Language=new Language; and then use $Language->Lang; to obtain the user language. So far so good.
This is the function I want to reconvert to a class. It gets an integer or a string, searches it as an id with mysql and returns a translated string in the right language. Now, how do I achieve this? Here it’s the text() function. It was used with globals, which is apparently a really bad practice.
function text($Id)
{
// Already defined and tested that are valid (sql injection avoided also)
global $Lang;
global $Url;
global $Version;
global $Banner;
if (!empty($Url["folder"])) $FullUrl = "/".$Url["folder"]."/";
else $FullUrl="/";
if (!is_int($Id)) $Id = mysql_real_escape_string( $Id );
$numargs = func_num_args(); // Get the number of arguments that are being passed.
if ($numargs == 2) // If there are actually two
$Var=func_get_arg(1); // Set $Var with the second value (1).
if (is_int($Id)) // If a number is being passed
{
// Add AND page='$FullUrl' to control scope of the strings translated
$results = mysql_query("SELECT * FROM translations WHERE id='$Id'") or die ('Could not query:' . mysql_error());
$row = mysql_fetch_assoc($results);
if (!empty($row[$Lang]) && !isset($Var)) echo stripslashes($row[$Lang]); // If there is some, echo it
elseif ($Var==1) return stripslashes($row[$Lang]); // If it is required to be a returned string, send it.
else error($FullUrl,$Lang); // If there is nothing there, calls error function.
}
else // If a string is being passed
{
$results = mysql_query("SELECT * FROM htranslations WHERE keyword='$Id'") or die ('Could not query:' . mysql_error());
$row = mysql_fetch_assoc($results);
if (!empty($row[$Lang]) && !isset($Var)) echo stripslashes($row[$Lang]); // If it exists in the table, echo it
elseif (!empty($row[$Lang]) && isset($Var)) return stripslashes($row[$Lang]);
else // Else (it doesn't exist)
{
$Id = str_replace("_", " ", $Id); // Replace the "_" with " "
if (!isset($Var))
{
echo $Id; // Echo the passed string with spaces
}
else return $Id;
$Banner="There might be some misstranslation. Please report if needed.";
}
}
}
So the text function has lots of side effects; meaning, it’s touching a lot of
stuff, and sometimes returning and other times printing stuff to
standard output. This is usually not good because it is hard to debug, unit-test
and refactor
I would go with option 2: Merge both classes into one. The language would be found
when initialized and a method called when needed.
Below is how I would implement this (I kept as much code intact as possible so you could understand
what was changed in regards to OOP. There are many other things I would change; mostly what others
have already commented on plus not printing anything from within the method. It’s good practice
to have methods return something and not modify the application state from within
Things I changed:
The text function was actually changing a global variable ($Banner) during certain
times, using two global variables ($Url) and ($Lang which is actually from the language
object) and then returning an Id from the database or possibly printing to
standard output.
Since moving the text function into the Language class, I converted the global $Lang
variable to use the instance variable $Lang of the Language class
The $Url method is only being used in the text function and thus, can be passed into the text method
The global variable $Banner is actually being set by the text function which I consider a bad
side effect. I decided to replace this code:
$Banner = “There might be some misstranslation. Please report if needed.”;
with
return false.
This way, if the text method returns false, you can set the $Banner
variable to “There might be some mistranslation. Please report if needed.” which
is done from outside of the object.
Also, I removed the global variable $Version from the text function becaue it was not used within
the function
I would also recommend working on having the text method only return and not print to the
standard output. Misstranslation is spelt wrong. It should be mistranslation.
I hope this helps…