I have custom config items in application/config/config.php.
Samples of my custom config items:
$config['website_title'] = 'ABC Website'; //Assume website title is fixed
.
.
.
etc
Now i can call $this->config->item('website_title') any where in my application. However, i don't find it efficient enough because i might have multiple $this->config->item('website_title') within the project. I came up with the following solution:
1.Create a function, within a helper, that return the config item as the following:
public function website_title() {
return $this->config->item('website_title');
}
2.Now i can call website_title() as many as i want.
Is this a good solution? Do you see any downsides?
Note: I try to avoid using global variables because i tried it and i
faced many unnecessary problems such as undefined variables,
surprised!
What do you mean by "efficient"? Runtime efficiency? Coding efficiency? Clarity?
In terms of runtime efficiency Truth's suggestion of using is perhaps the simplest and best. However, I prefer to code using a strict class/object implementation, and in reality defines are just global constants.
If you profile the vast majority of scripts, you will find that however you code your configuration referencing makes an immaterial impact on runtime, so I would suggest going for simplicity and clarity of coding every time.
One approach is to use a singleton class (there are lots of tutorials on doing this) and use the magic method __get() to allow you to dynamically overload parameter access. This is one case where I feel that you have to use a single class as these property methods only work with object (non-static) parameter references. Hence you can simply use:
$cfg = Configuration::get();
...
... $cfg->someConfigParam ... // to refer to a config parameter
...
... /* or even */ ... Configuration::get()->someOtherParameter ...
Note that $cfg in the above example essentially stores an object handle, so there is no material runtime cost in doing this, and you can put this statement at the top of each function or class constructor that references a config item if you don't want to litter your code with Configuration::get()->someOtherParameter type calls.
The Configuration::__get() access function , plus the class constructor can handle all the complexities of caching and access of the individual parameters. This also means that you con also encapsulate the source of the configuration: some application-specific D/B config table; one or more config files, ...; even cookies or URI parameters (so long as you include appropriate validation).
I personally don't recommend over loading with the __set() magic method as, IMO, overriding or setting a config parameter should be an explicit action, e.g. $cfg->setConfigItem( 'someValue', TRUE );
Here is a link to the documentation on my config class if you want some ideas.
I asked this sort of question on programmers once. I got a very good answer, simply use constants.
I.e. WEBSITE_TITLE
Related
I'm trying to improve my website engine. So I can stop setting global $vars inside functions
So now I'm setting all my global site vars with this instead:
define('ROOT_prefix', 'mysitename_');
define('ROOT_support', 'support#mysite.com');
I can access them anywhere. But it does not feel as good (or smart) practice..
I know very little about classes.. but couldn't/should't I use a class for this instead?
This works:
class ROOT {
public static $prefix = 'mysitename_';
public static $support = 'support#mysite.com';
}
And then anywhere on my site I can use this (even inside functions):
echo '<h1>Please contact support at: '.ROOT::$support.' </h1>';
Is this a good way, or is there a better way?
If the value of these "globals" will not be changed for the entire run-time of the script, then you absolutely should use constants, as this is exactly what they are for.
You should keep them all centralized in a common include file for readability.
(Edit based on comments follows)
Since it looks like you're using constants for some kind of localization of content, it might be prudent to use a class for this. As I have said: using constants for non-changing values in a procedurally oriented script isn't bad practice in itself, but in the context of localization, there are better ways.
One such would be to create a class with some static methods to translate a string based on the passed ini file, this would be in line with the dependency injection mentioned in other comments and answers here.
An example of such a class would look something like this:
class Localizer {
public static function localize($langFile, $string) {
if (!file_exists($langFile)) {
throw new Exception($langFile . 'not found!');
}
$lang = parse_ini_file($langFile);
return (!empty($lang[$string])) ? $lang[$string] : false;
}
}
You can use it like this:
echo Localizer::localize('./english.ini', 'hello') . "\n";
echo Localizer::localize('./english.ini', 'email') . "\n";
This assumes an ini file that looks like this:
; english.ini
hello = 'Hello!'
email = 'test#test.com'
Realistically, this is probably a more "proper" way than declating a boat load of constants for each language your application runs in, but it is going to open the file every time you need to localize a string, which wouldn't be optimal for a very high volume application on a large system. But, as with a constant, you will be able to access the static methods of a class in the scope of any function in your application so long as the class was included beforehand. No need to use constants or declare globals.
The most proper and efficent way to do it would be to instantiate a class instead of using static methods, which would load the files into memory once and keep them there, eliminating the need to open the file for every string translated. But this would require that you are able to pass the variable containing the instantiation of this class to every function in your code that requires it, or declare it as global, which was exactly what you were trying to avoid in the first place.
So in order to do this, you would probably need to re-structure your code to allow for dependency injection throughout.
To continue with your current code and structure, you can continue using generated constants, which will be much messier, less "proper", and not expandable, but the advantage is that you will only read the ini files once, and keep them in memory.
Or you can use a static method, which is more "proper" but needs to read a file every time you localize a string, meaning that on large systems, it could cause some inefficiency. Realistically though, if your application in low volume, you will likely never see problems arise from this.
The main advantages of this method are expandability, and clean code. While declaring constants might be more efficient in terms of file opening and memory usage in the very short term, in most cases, it's not as expandable, because you can have an unlimited number of strings and language files, which means you could end up in a situation in the future where your loading thousands and thousands of constants every time your application loads.
If you use a class, and only load the files/strings that are needed by that specific user at run time, you can avoid this, no matter how many languages and strings you support.
Static class variables aren't any better than constants. They're still globally accessible values. There's no real change.
If you want to be improving your style, you should be using dependency injection. This simply means that you pass all variables that a function or class needs into the function/class as parameters. It's that simple, really. If you want to decouple your code, you need to create borders between different pieces. That means one piece does not "reach out" and get a global variable; instead you define that piece as accepting a parameter and write another piece that passes it that parameter.
Please read How Not To Kill Your Testability Using Statics for an in-depth explanation of this topic.
You may set variable to global when you need it. Just use global ${$variablename};.
where $variablename contain name of needs variable. For example it may be array keys or values.
Declaring your properties as public allows for their modification.
If you want them to be constants, as they were when created with define, you'll have to declare them as protected and use methods to access them :
class ROOT {
protected $prefix = 'mysitename_';
protected $support = 'support#mysite.com';
public static getPrefix(){
return $this->prefix;
}
public static getSupport(){
return $this->getSupport;
}
}
This way is actually quite better than using define() actually.
It's a step forward to singleton patterns (http://en.wikipedia.org/wiki/Singleton_pattern).
Next step is the building of an Application class (ROOT name sounds fine) which would contain these constants, and perhaps load them from a configuration file.
In this Application singleton, you can build some main function, like an init() for a bootstrap, inclusion of other classes, database configuration, logging system, templating system, and so on...
I built some the following i18n function which is called several times when rendering view :
function e_($text)
{
$t = Translate::Instance();
vprintf($t->_($text), array_slice(func_get_args(), 1)); // outputs translated text
}
Currently, I get the instance of the Translate singleton Class inside the function.
I've read that dependency injection should be used instead.
But If I do use dependency injection, I will have to pass the Translate object each time into the function, right ?
This would became :
<?php e_('my text', $this->Translate);
and not simply <?php e_('my text'); ?>
Well I'd like to avoid that.
The way you use the e_ function is actually using an alias. That's fine as long as you can live with it. You don't need to use a singleton to implement an alias:
function e_($text)
{
return $GLOBALS['e_alias']->alias(func_get_args());
}
When setting up the view layer, set the dependency:
$GLOBALS['e_alias'] = $translate;
In application context, set the global variable $translate. This will allow you to move away from the singleton (which are liars), and you actually only need a global variable.
Additionally it allows you to test views with the e_ alias against different translation implementations.
The downside is that you need to manage a list of all these special global variables, like you need to maintain for the global functions like e_.
See as well this answer to the Getting $this inside function question.
True. The reason you would use dependency injection instead is so that you could swap out the translation method for any particular use of e_().
In this particular case, I'm not sure it would be worth it unless you wish to test different translation methods during testing.
One thing you could do to help a little with performance is make $t static so that Translate::Instance() is only ever called once no matter how many calls to e_() are made.
coming from Java, I only have a few vacational visits to PHP. Looking at magic get and set methods, my (Java influenced) tummy starts hurting: It looks as if you were accessing properties directly (although, of course, you are actually are using __get and __set).
So - except for less code you have to write, are there any advantages to using magic getter and setter methods instead of traditional getX()/setX() methods? Should I start using them when coding PHP?
Thanks and best!
The only benefit of __get() is the possibility of less code, but even then it's not necessarily the case. For example, if you have a set of 10 private members and you want the getter to reveal 5, you have to write __get() so that if one of the psuedo-visible members is called, you send it. Otherwise, you either issue an error (that would otherwise come naturally without __get() or return a value such as null that may not actually be helpful.
I must excoriate anyone who suggests using getters and setters in general at all. This usually indicates a problem with architecture. Explain the conceptual difference between the two following code blocks, for instance:
class _ {
public $_;
}
vs.
class _ {
private $_;
public function get_() {
return $this->_;
}
}
There isn't a difference.
However, as many will point out the advantage of having a getter is that this allows you to modify the return value in some way transparently to make it useful for the recipient. However, we come back to architecture problems. You should never have to expose the contents of a class for any reason at all. Instead, you should tell the class to perform an action (which may vary based on its state). Using getters generally lends to querying the class' state and performing an action externally based on the viewed state.
I have essentially the same arguments against __set() and setters, but there is one nice thing that __set() lets you do:
class _ {
private $_ = array();
public function __set($key, $val) {
$this->_[$key] = $val;
}
}
This lets you type the very nice $_obj->key = 'val'. Note that there is not much difference from this and adding another method such as add() that takes the key and value and does the same thing, I just prefer the object setter notation.
__get__ and __set__ are fully dynamic. So for example you can start a database request if they are called to enable lazy loading. Of course, you could do this with getters and setters, too, but then you would have to do this every time. You can also do something like AOP because every property call gets passed through one single method. So all in all __get__/__set__ offer more flexilibility against time they take to process. You can do really advanced/cool stuff with it.
The advantages are that when you're refactoring, direct assignments / reads can be handled without the need to immediately change the complete codebase too, the code can be somewhat shorter, and people can create strings somewhat more easily (for example: $title="<title>{$obj->title}</title>"; vs. $title='<title>'.$obj->getTitle().'</title>';.
However, __get & __set methods can become large and unwieldy fairly quickly, and when coding properly & explicitly, it is in my opinion better to use explicit set/getX() methods to make clear functions are called, and the minor increase of code verbosity is as far as I'm concerned justified as one can easily see what actually calls a function and what doesn't. A possible exception could be when you are building a decorator for another class/object, but that's about it.
there is few difference between getter and setter methods and __set() and __get() methods! these are magic methods!
__set() use when you wanna assign undefined state to a object and so __get() also use to fetch value of undefined state!
setter and getter are used to assign or fetch value of defined states
except for less code you have to write, are there any advantages to using magic getter and setter >methods instead of traditional getX()/setX() methods? Should I start using them when coding PHP?
Given that less code to write it's already a strong reason to start use them.
the other reason is that you can add a common behaviour to all your getter/setter
function __set() {
//> Do some code in common between all setter
//> set your var here
}
When writing getX()/setX() for each attribute, practically speaking, you'll have at a minimum, 7 lines of code. This is assuming that your opening method brace is on the same line as the definition and you only put a single line of code into the method, then you have your closing brace on its own line.
For a non-trivial object, multiply that by 6 (YMMV). That is 42 lines just for attribute access/mutation. That does not include input validation or normalization. For an alternative, check out: https://github.com/metaphp/attributes
There are overheads in dynamic programming (e.g. using magic methods). An old benchmark: Benchmarking magic
As PHP is a dynamic (and not a completely enterprise) language, reducing code lines and missing some nanoseconds seems good idea in many cases (for debugging, scalability, reducing errors and etc).
i have an application done in php and all configuration variables are loaded in a big $conf variable at the beginning of the script.
What is the better way to communicate this configuration variable to all other functions ?
make it a parameter of every function ? or use it with "global $conf;" statement in every function ?
is there a better way to do ?
Thanks
Use PHP constants.
For ponies sake, avoid using global variables at all costs :)
EDIT
Some explanations about "avoiding global variables at all costs" and possible alternatives:
https://stackoverflow.com/questions/357187/when-are-global-variables-acceptable/357361#357361
http://my.opera.com/zomg/blog/2007/08/30/globals-are-evil
https://stackoverflow.com/questions/1285700/what-are-some-good-tips-for-a-new-php-developer (especially section Scope of the accepted answer)
Make a configuration class that stores the options. Make it a singleton PHP Manual describes that here. This is just an alternative to global variables. It would allow you to define a method to load options from a file or a php array and store them in the class. Other classes can use the configuration object by getting the single instance and accessing the data.
I think this is better than a global variable as the other answer also says. But it still lets you define options as arrays, or even nested arrays if you want (and set up your class accordingly)
Your use of a single global-scoped variable $conf is perfectly fine. Many PHP applications do that. But there are drawbacks to combat.
In particular it's often more effort to write global $conf in each function where you want to access them. In that case I would recommend a simple global wrapper function instead:
function conf($key, $sub="") {
global $conf;
if (defined($key))
{ return constant($key); }
elseif ($sub)
{ return $conf[$key][$sub]; }
else
{ return $conf[$key]; }
}
This allows you to write conf("setting1") or conf("main", "opt3") whereever you need it. Still you can access the global $conf where that is more suitable. As extra bonus you can make this wrapper function more intelligent, by allowing it to query alternative settings etc. Also see how easy it is to also sneak in conf("CONSTANT") support.
Keeping this adds some flexibility in defining your configuration settings. Personally I use a similar approach, albeit with defining the array step-wise rather than at once:
$app_config["title"] = ...;
$app_config["editor.btns"] = ...;
define("RESTRICTED_MODE", true);
I'm preferring the array() approach, but transitioning to an ini-file for storage at a later point is not a problem. Also you can still make your config array read-only if the need arises. For that just define an:
class Read_Only_Array extends ArrayObject { function offsetSet() {} }
$conf = new ReadOnlyArray($conf);
So it's still accessible as array, but you easily established what others use cumbersome registries or syntactic workarounds for.
The "globals are evil" meme is completely baloney. It's parrotted on SO by cargo cult programmers with a desire for oversimplification and newcomers who glance over bold headlines without understanding the language semantics.
In your case, you just use a single $conf variable, and do not pollute the shared scope. When it is coherently accessed from the whole application, then it's not an issue. You should however strictly avoid to modify contents at runtime (use Read_Only_Array if need be). Create a secondary $app_var[] aray for that, and keep your config settings static.
On my site I have a config file which has many settings that need to be accessed in many pages, including inside many class files. The config file is included into the header of every page build. Since I will be using a registry method to store some objects in, I am wondering if it would be better for me to store some setting in this class ass well since it will be available to all my other objects? From my experience over the last couple days, it seems accessing CONSTANTS inside of my class files is difficult sometimes. I am just not sure if it would be a good idea as it would need to call several methods to set and get the settings. Is it common practice to store settings in a registry type object? I have seen on some large projects that they have the methods in place to set/get settings but I have never really seen it in action.
I avoid constants in PHP, they make untestable. This is the gist of my preferred solution:
whatever.ini:
<?php
return array(
'setting-1' => 'value',
'setting-2' => 'another value',
);
config.php:
class config
{
public function __construct($path)
{
$this->cfg = include $path;
}
private $cfg;
public function get($key, $default)
{
return array_key_exists($this->cfg, $key)
? $this->cfg[$key]
: $default
;
}
}
index.php:
$cfg = new config('my.ini');
...
I like to keep things like this in a registry of some sort. Although for me this is because
the majority of my configuration
values are actually multiple parts
(ie arrays) so to map much of this
out using constants would get pretty
long winded. Additionally i dont
use php for my config files i always
use XML or YAML which is then parsed
any way so it jsut makes more sense
to go ahead and stick them in a
registry as opposed to using constant or globals.
It allows for a single api to get
these type of values whther its a db
connection object or the path to the
webroot on the filesystem
With that said i think it really depends on what the values are and how you intend to use them and if they are structure or essentially flat.
I use a combination of two approaches:
1: In every class/controller, I always start with a require_once('app_config.php') in which I have code like:
define('APP_SMTP_SERVER', 'mail.company.com');
that I can then reference as a constant.
2: I have a singleton "Registry" class where I can store keys and values. It has two exposed methods, getAttribute($key) and setAttribute($key, $value). When I save it to the database, I serialize the value, so it can store any data type you throw at it (single values or arrays, etc.).