exclude certain fields conditionally on a API resource

@Sinnbeck no, I want to exclude fields on the UserResource which is a subset of the resource fields shown in my example.

@panthro then do it in that resource? Can you show the resource if you are in doubt (and an example of what should be hidden by what)

@Sinnbeck I don't want to do it in that resource. For example, a user resource should return everything for the user, but when a user is loaded on a related model such as a post, I want to exclude items such as the related users email.

.... Other fields
'user' => new UserResource($this->whenLoaded('user')), // the related model resource - exclude `email` required
'start_date' => $this->when($this->start_date, $this->start_date), // a field on the `post` resource
 'end_date' => $this->when($this->end_date, $this->end_date),
.... Other fields

@panthro Untested, but you could perhaps try something like this

'user' => collect(new UserResource($this->whenLoaded('user'))->toArray($request))-only(['name'])->toArray(),

@Sinnbeck nice idea, but fails when the relationship is not loaded (what the $this->whenLoaded is for).

@panthro Above the code..

if (! $this->resource->relationLoaded('user')) {
          $user = null;
} else {
   $user = new UserResource($this->resource->{$relationship}->only(['name']));
}

Or

'user' => new UserResource($this->whenLoaded('user', function() {
       return this->resource->user->only(['name']);
}),

@Sinnbeck afraid not Attempt to read property \"username\" on array"

@panthro which example?

this was for your first response, I will now try your second response - thanks!

With this:

'user' => new UserResource($this->whenLoaded('user'), function () {
                dd('i never die!');
            }),

Seems like fnc never called as it never dies.

@panthro but there is a user relation returned?

Oops. Remove the )

$this->whenLoaded('user', function

@Sinnbeck yes I can now die.

But same error Attempt to read property \"username\" on array

I suspect what is happening, we are filtering the user correctly and only returning one field, but when its wrapped in the UserResource, it's looking for all of the other fields and failing:

UserResource:

 public function toArray($request)
    {
        return [
            'username' => $this->when($this->username, $this->username),
            'email' => $this->when($this->email, $this->email),
            'url' => $this->when($this->url, $this->url),
            'bio' => $this->when($this->bio, $this->bio),
            .....

@panthro do a dd() on what you have in the function and post it

'user' => new UserResource($this->whenLoaded('user', function() {
       dd(this->resource->user);
}),

@Sinnbeck I get the user model:

App\Models\User {#1402
  #fillable: array:6 [
    0 => "username"
    1 => "email"
    2 => "password"
    3 => "url"
    4 => "bio"
    5 => "newsletter_opt_in_at"
  ]
....

This:

dd($this->resource->user->only('username'));

Gives:

array:1 [
  "username" => "camron08"
]

@panthro Try this

dd($this->resource->user->makeHidden(['password', 'email']));

@Sinnbeck returns the user model, with those fields under hidden

App\Models\User {#1402
  #fillable: array:6 [
    0 => "username"
    1 => "email"
    2 => "password"
    3 => "url"
    4 => "bio"
    5 => "newsletter_opt_in_at"
  ]
  #hidden: array:5 [
    0 => "email"
    1 => "password"
    2 => "remember_token"
    3 => "password"
    4 => "email"
  ]

If you do this in the fnc:

$this->resource->user->makeHidden(['password', 'email']);

return $this->resource->user;

The email address is still returned.

@panthro Ok this then

'user' => new UserResource($this->whenLoaded('user', function() {
       $user = $this->resource->user;
$fake = new User;
$fake->username = $user->username;
return $fake;
}),

@Sinnbeck that works!

@panthro Sweet. Please mark a best answer

@Sinnbeck no problem, thanks for your help.