Select an unpersisted entity - php

Question

I'm using a twig for loop to display a list of elements. These elements come from a decoded json array, from an API.
I have a OneToMany relation between my user and these elements.
User needs to chose one of these elements, which will be added to the user with the addElement() function.
I tried to do so using a Symfony2 form in the loop, but it is only displayed on the first element. I also tried using a link to a controller function, but since none of these elements are persisted in my DB, I got this error:
"Unable to guess how to get a Doctrine instance from the request information."
Here's how I display my elements:
{% block itinerary %}
{% for element in elements %}
<aside class="flights-results__by-price col-md-3">
<span class="flights-results__price">{{ element.price ? element.price : 'Unknown' }}</span>
Delete
</aside>
{% endfor %}
{% endblock itinerary %}
Here is the function where I create and fill my elements :
public function getAvailabilities($availabilities, $planes, $airports)
{
$reservations = array();
foreach ($availabilities as $ar)
{
$leg = new Leg();
$leg->getId();
foreach($ar as $a)
{
$leg = $this->fillLeg($leg, $a);
foreach($a->availabilities as $aleg)
{
$leg->setAirplaneType($this->findPlane($planes, $aleg->airplane_type_id));
$leg->setAirportStart($this->findAirport($airports, $a->lfi_from));
$leg->setAirportEnd($this->findAirport($airports, $a->lfi_to));
$leg->setDurationLeg($aleg->duration);
$leg->setEndHour($aleg->datetime_to);
}
$startdate = $a->datetime;
}
$reservations[] = $leg;
}
return $reservations;
}
and here is the result when I dump($elements) :
FlightController.php on line 55:
array:4 [▼
0 => {#953 ▼
+"3e1f975601f59090decc8f2d5ced72010162e48e": {#954 ▼
+"lfi_from": "FR58957"
+"lfi_to": "FR45300"
+"datetime": "2015-09-10 20:00:00"
+"nb_pax": "4"
+"availabilities": array:1 [▼
0 => {#955 ▶}
]
}
}
1 => {#956 ▼
+"3e1f975601f59090decc8f2d5ced72010162e48e": {#957 ▼
+"lfi_from": "FR45300"
+"lfi_to": "AG00060"
+"datetime": "2015-09-10 23:00:00"
+"nb_pax": "4"
+"availabilities": array:1 [▼
0 => {#958 ▶}
]
}
}
2 => {#959 ▼
+"3e1f975601f59090decc8f2d5ced72010162e48e": {#960 ▼
+"lfi_from": "FR45300"
+"lfi_to": "AG00060"
+"datetime": "2015-11-30 23:00:00"
+"nb_pax": "4"
+"availabilities": array:1 [▼
0 => {#961 ▶}
]
}
}
3 => {#962 ▼
+"3e1f975601f59090decc8f2d5ced72010162e48e": {#963 ▼
+"lfi_from": "FR45300"
+"lfi_to": "OLOLOL"
+"datetime": "2015-09-18 23:00:00"
+"nb_pax": "2"
+"availabilities": array:1 [▼
0 => {#964 ▶}
]
}
}
]
The main problem is that the API returns several thousands results. For obvious reasons, I cannot persist them all.
I guess the easiest way to ask would be "What is the best way to send datas on an entity to another function in my controller, without persisting this entity?". So far, I've always worked with persisted elements, with an id as identifier, but I realize it gets trickier when we deal with non-persisted entities.

Answer 1

If you have a OneToMany relation between your User and these Elements, it means the Elements are persisted somehow. So why can't you use the id of the element ?
In case you persist it, you may need to add a ParamConverter in your controller code somewhere along those lines:
/**
* #Route("/selectLeg/{element}")
* #ParamConverter("element", class="YourBundle:Element", options={"mapping": {"name": "element.whatever_param"}})
* #Template()
*/
public function selectLegAction(Element $element)
The fact is, if Symfony2 doesn't know about your Element entity, you won't be able to do addElement() to your User.
What I guess is that you get the elements' list in the frontend and then try to update your User object. In this case I would json_encode your element in Twig (it's a simple array after all if I understand) :
Select this leg
and create a new Element in your controller :
/**
* #Route("/selectLeg/{legAsJSONString}")
*/
public function selectLegAction($legAsJSONString) {
$e = json_decode($legAsJSONString);
$leg = new Leg();
$leg->setWhateverParameter($e->parameter_in_the_array);
// more parameters here
$em->persist($leg)->flush();
/// Now here you have $leg->getId(); if ever you need it
}
EDIT : Adapted to your comment. If you don't need to persist the element (leg) before the user has chosen a particular one, then send the element in string form in a GET parameter, in the route parameters, or in the data of a POST request (cleaner solution). You don't need the id since you can pass the full object in the request, as a JSON string.
Remove your useless $leg->getId(); from getAvailabilities() as well, it doesn't actually do anything, and the id doesn't exist anyway.
If I miss the point and that the $leg object is too complicated and therefore not serializable in JSON, then you will need to persist it since two consequent requests will need to have access to it.