Laravel: How to Append Properties to an Array - php

Question

I have an array that gets returned from my show method. This is the show method:
public function show($id)
{
$track = Fuelconsumption::where('id', $id)->first();
return $track;
}
Returns this:
{
id: 6,
distance: 178.6,
volume: 14.31,
price: 1.45,
date: "2015-11-08 14:13:56",
created_at: "2015-11-30 03:29:57",
updated_at: "2015-11-30 03:29:57"
}
I want to make some calculations (averages etc.) from the values provided and append these variables to above json array.
Right now I am solving the problem, by creating a new Kpi object in a new KpiController. The controller passes the above array (which is a FuelConsumption Object) to my constructor.
This is the show method of my KpiController:
public function show($id)
{
$item = Fuelconsumption::where('id', $id)->first();
$kpi = new Kpi($item);
return $kpi['list'];
}
Constructor of my Kpi class:
protected $avgFuel;
protected $avgCost;
protected $cost;
protected $list;
/**
* Creates all necessary KPIs
*
* #param Object $item Fuelconsumption
*/
public function __construct(Fuelconsumption $item)
{
$this->avgFuel = $this->avgFuelperUnitofDistance($item);
$this->avgCost = $this->avgCostPerUnitOfDistance($item);
$this->cost = $this->cost($item);
$this->list = [
'avgFuelperUnitOfDistance' => $this->avgFuel,
'avgCostperUnitOfDistance' => $this->avgCost,
'cost' => $this->cost
];
}
And it returns a Json array that looks like this:
{
avgFuelperUnitOfDistance: 0.08,
avgCostperUnitOfDistance: 0.116,
cost: 20.75
}
The problem I have now is that the first array gets returned when I visit the following URI:
http://localhost:8000/fuelconsumption/6
And the second array gets returned when I visit this URI:
http://localhost:8000/fuelconsumption/6/kpi
The problem is that I want both Json Arrays to be combined in one Array and I am not sure how to accomplish this.
HERE ARE MY THOUGHTS:
Modify Fuelconsumption Class
Modify my FuelConsumptionController to this:
public function show($id)
{
$item = Fuelconsumption::where('id', $id)->first();
$kpi = new Fuelconsumption($item);
dd($kpi);
}
And have a constructor in my Fuelconsumption class:
class Fuelconsumption extends Model
{
protected $fillable = ['distance', 'volume', 'price', 'date'];
protected $dates = ['date'];
protected $cost;
public function __construct($item) {
$this->cost = $this->cost($item);
}
public function cost($item) {
return round($item->volume * $item->price, 2);
}
}
This unfortunately throws the error:
Missing argument 1 for App\Fuelconsumption::__construct()
In my understanding because the class is called even before I recall it in my controller a 2nd time. Not sure how to solve this.
Second Thought: Expand the KPI object
To include all other variables I want to have and then somehow return in my FuelConsumptionController#show method the complete array.
Third Thought: Somehow combine these arrays
Not sure how.
Right now I believe the easiest solution would be to expand on the KPI model (Second Thought of mine), yet I hoped to get rid of the KPI class altogether by somehow passing the item to my FuelConsumption constructor.

Answer 1

Your almost right.. because your class FuelConsumption is an Eloquent model the __construct is already been setup by Laravel and your tried to override it.
What Eloquent does is in case of using ->first() or ->find($id) returning a single model (like what you have). When using ->all() or ->get() it is returning a Eloquent Collection.
Suggestible approach:
class Fuelconsumption extends Model
{
protected $fillable = ['distance', 'volume', 'price', 'date'];
protected $dates = ['date'];
protected $cost;
public function cost() {
return round($this->volume * $this->price, 2);
}
public function avgFuelperUnitofDistance() {
return $this->distance / $volume; // do your thing, dummy calc
}
public function avgCostPerUnitOfDistance() {
return $this->distance / $price; // do your thing, dummy calc
}
}
And your api controller method could look like:
public function show($id)
{
$item = Fuelconsumption::find($id)->first();
// if $item == null if it is item was not found
if (!$item) {
return response('item was missing', 404);
}
// $item will look like:
// class Fuelconsumption: {
// id: 6,
// distance: 178.6,
// volume: 14.31,
// price: 1.45,
// date: "2015-11-08 14:13:56",
// created_at: "2015-11-30 03:29:57",
// updated_at: "2015-11-30 03:29:57"
// }
// doing more stuff over here
// create the json response
return response()->json([
'id' => $item->id,
'distance' => $item->distance,
'volume' => $item->volume,
'price' => $item->price,
'date' => $item->date,
'cost' => $item->cost(),
'avg_fuel' => $item->avgFuelperUnitofDistance(),
'avg_unit' => $item->avgCostperUnitofDistance(),
]);
}
or if you really want to create and merge the attributes:
public function show($id)
{
$item = Fuelconsumption::find($id)->first();
.....
$extra = [
'cost' => $item->cost(),
'avg_fuel' => $item->avgFuelperUnitofDistance(),
'avg_unit' => $item->avgCostperUnitofDistance(),
];
return array_merge($item->getAttributes(), $extra);
}

Answer 2

Another way to solve it would be the suggestion by user naneri with this link:
http://laravel.com/docs/5.1/eloquent-serialization#appending-values-to-json
Then my model would look like this:
class Fuelconsumption extends Model
{
protected $fillable = ['distance', 'volume', 'price', 'date'];
protected $dates = ['date'];
protected $appends = ['cost', 'avg_fuel_per_unit_of_distance', 'avg_cost_per_unit_of_distance'];
public function getCostAttribute()
{
return round($this->attributes['volume'] * $this->attributes['price'], 2);
}
public function getAvgFuelPerUnitOfDistanceAttribute()
{
return round($this->attributes['volume'] / $this->attributes['distance'], 3 );
}
public function getAvgCostPerUnitOfDistanceAttribute()
{
return round($this->attributes['volume'] * $this->attributes['price'] / $this->attributes['distance'], 3);
}
}
And the output of my show method would look like this when getting the URI http://localhost:8000/fuelconsumption/6
{
id: 6,
distance: 178.6,
volume: 14.31,
price: 1.45,
date: "2015-11-08 14:13:56",
created_at: "2015-11-30 03:29:57",
updated_at: "2015-11-30 03:29:57",
cost: 20.75,
avg_fuel_per_unit_of_distance: 0.08,
avg_cost_per_unit_of_distance: 0.116
}