Laravel set global variable for all custom helpers,controllers, and models

Question

i've ever asked this question before in codeigniter, now I want to ask about this in laravel.

I want to set a global variable for custom helpers, models, and controllers the variable is got from database result..

Here is the example:

don't know where to put the variable

 $data= DB::table('categories')->where('id', '2')->first();
 $this->product_var = $data->product;  **//main global variable**

custom helper

function test() {
    if($this->product_var=="product name") {

    }
}

my controller

function index() {
    echo $this->product_var;
}

my model

function get_data() {
     echo $this->product_var;
}

As you can see my scripts above, $this->product_var is almost used for custom helper, my controller, and my model. in codeigniter we create Globals.php in libraries folder, or just put the variable in core controllers. Where should i set the global variable?

@Tpojka i have so many variables. is it best practice to add all variable in session? — Willyanto Halim, May 22 '17 at 08:27

score 12 · Accepted Answer · answered May 24 '17 at 11:47

Like @Mozammil mentioned:

The idea is to use the "Laravel configurations". This allows you to keep values in global scope for one request cycle.

You can access these value through out the application using the config() helper of Laravel.

You just need to set it once like:

config(['app.product_data' => $data]);

And, this will be available for you globally in the application just use config('app.product_data') to access the data.

Like:

In custom helper

function test() {
    if(config('app.product_data')->product_var=="product name") {
         //do something
    }

}

Your controller

function index() {
    echo config('app.product_data')->product_var;
}

Your model

function get_data() {
     return config('app.product_data')->product_var;
}

Hope this would help.

score 11 · Answer 2 · answered May 25 '17 at 12:12

Config is not a good way to hold a global variable. As the framework suggests config should only contain configuration for your project. And they should be independent of request.

Laravel provides much better way to handle global variables, you can use Singletons. Why? Because a singleton holds on to application a deepest level, it can be called and available at in part of request. Once declared its pretty hard to change singleton in the middle of request.

You can put this code in Your AppServiceProvider or you can create your own ProductVarServiceProvider.

App::singleton('product_var', function(){
     return DB::table('categories')->where('id', '2')->first();
});

This is way you can we sure about the origin of product_var. Later you can use helper function app('product_var') anywhere in you code.

You should be careful when declaring global variables.

Perfect, because singleton is perfect way here to get uniform value everywhere in application. But i have doubt, will it fire query single time or everytime its being called ? — Pratik Soni, May 29 '17 at 13:59
No, once is singleton resolved, laravel will holds to its value. — anwerj, May 29 '17 at 14:09

score 5 · Answer 3 · answered May 22 '17 at 09:02

I recently answered a question whereby the author had a very nice way of globally caching table values.

The idea is that he was fetching table values (also caching it) and he made a Settings ServiceProvider to be able to access it as a configuration variable later on.

Maybe this would work out very well for you too.

score 2 · Answer 4 · answered May 29 '17 at 14:22

Another simplest way to manage multiple data at same time.


     <?php

        namespace App\Utilities;

        class DataBus
        {
            private static $data = [];

            public static function setData($key, $value)
            {
                self::$data[$key] = $value;
            }

            public static function getData($key)
            {
                if(isset(self::$data[$key]))
                {
                    return self::$data[$key];
                }

                throw new \Exception("key is not set");
            }
        }

Use it like this way

<?php

namespace App\Xyz;

use App\Utilities\DataBus;


class ABC{

    function setData()
    {
        $data= DB::table('categories')->where('id', '2')->first();

        DataBus::setData('product_var', $data->product);

        // get data by below syntax anywhere in application after setting data.

        DataBus::getData('product_var');
    }
}

Laravel set global variable for all custom helpers,controllers, and models

4 Answers4