Constraining a nested 3rd level relationship - laravel

Question

I'm building an api using eager loading so i can simply return the user model with its deep relations and it automatically be converted as json. Here's the set up.
users
id
..
clients
id
..
user_clients
id
user_id
client_id
..
campaigns
id
..
client_campaigns
id
client_id
campaign_id
..
campaign_activities
id
campaign_id
..
client_campaign_activity_templates
id
campaign_activity_id
client_id *(templates are unique per client)*
..
I've setup the models' relationships.
User
public function clients() {
return $this->belongsToMany('App\Client','user_clients');
}
Client
public function campaigns() {
return $this->belongsToMany('App\Campaign','client_campaigns');
}
Campaign
public function activities() {
return $this->hasMany('App\CampaignActivity');
}
CampaignActivity
public function templates() {
return $this->hasMany('App\ClientCampaignActivityTemplate')
}
I have a simple api endpoint to provide a JSON of a User object including its deep relations using eager loading.
public function getLoggedInUser(Request $request) {
return \App\User::with('clients.campaigns.activities.templates')->find($request->user()->id);
}
Testing this using postman, I can get the user including its deep relations.
{
"user": {
"id": 1,
"name": "user1",
"clients": [
{
"id": 1,
"name": "client1",
"campaigns": [
{
"id": 1,
"name": "campaign1",
"activities": [
{
"id": 1,
"name": "activity1",
"templates": [
{
"id": 1,
"name": "template1 for client1",
"client_id": 1,
"body": "this is a template.",
}, {
"id": 2,
"name": "template1 for client2",
"client_id": 2,
"body": "This is a template for client2"
}
]
}, {
"id": 2,
"name": "activity2",
"templates": []
}, {
"id": 3,
"name": "activity3",
"templates": []
}
]
}
]
}
]
}
}
However, on the user->clients->campaigns->activities->templates level, it will list all the templates for that activity. I know based on the code of the relationships of the models above that it's supposed to behave like that.
So the question is How would you filter the templates to filter for both campaign_activity_id and client_id?
I've been experimenting on how to filter the templates so it will only list templates for that activity AND for that client as well. I have a working solution but it's N+1, I'd prefer eloquent approach if possible. I've been scouring with other questions, answers and comments for a closely similar problem, but I had no luck, hence I'm posting this one and seek for your thoughts. Thank you

Answer 1

I think what you need are eager loading constraints.
public function getLoggedInUser(Request $request) {
return \App\User::with('clients.campaigns.activities.templates',
function($query) use($request) {
$client_ids = Client::whereHas('users', function($q) use($request){
$q->where('id', $request->user()->id);
})->pluck('id');
$query->whereIn('templates.client_id', $client_ids);
})->find($request->user()->id);
}
Not tested but it should only require one additional query.
What I am doing is: define a constraint for your eager loading, namely only show those templates that have a client_id that is in the list (pluck) of Client IDs with a relation to the User.

Answer 2

Try using closures to filter through related models:
$users = App\User::with([
'clients' => function ($query) {
$query->where('id', $id);
},
'clients.campaigns' => function ($query) {
$query->where('id', $id);
}
])->get();

Answer 3

Here's my working solution, but I'm still interested if you guys have a better approach of doing this.
On the CampaignActivity model, I added a public property client_id and modified the relationship code to
CampaignActivity
public $client_id = 0
public function templates() {
return $this->hasMany('App\ClientCampaignActivityTemplate')->where('client_id', $this->client_id);
}
and on my controller, limit the eager loading to activities only (actually, there are more sqls executed using eager loading[9] in this case vs just iterating[7], and also eager loading doesn't make sense anymore because we're iterating lol)
public function getLoggedInUser(Request $request) {
foreach ($user->clients as $client)
foreach( $client->campaigns as $campaign)
foreach ($campaign->activities as $activity) {
$activity->client_id = $client->id;
$activity->templates; //to load the values
}
return $user;
}