How to dynamically change a Model attribute in a controller? - php

Question

I have two tables users and users_metadata, where a single user hasMany metadata.
When I'm fetching all of the users, I want to be able to select certain fields, some of which exist in the metadata table.
users - id:1
users_metadata - user_id:1, key:username, value: MyUsername
users_metadata - user_id:1, key:birthday, value: 2017-11-16
Through the url, I can add on a fields attribute which lists what fields I want to select rather than all of them.
/api/v1/users?fields=username
What I'd like to be able to do is, instead of fetching all the metadata is to just fetch the metadata which is listed in the fields.
// Are we selecting all the fields?
if(!is_array($fields))
{
// We are not, so lets build an array
$fields = explode(',', $fields);
// Loop through the users
foreach($users as $user)
{
// Loop through the fields
foreach($fields as $field)
{
// Try to fetch it as metadata
if(array_key_exists($field, $user->metadata->toArray()))
{
$metadata[] = $field;
}
}
// Adjust the user metadata
$user->metadata = $user->metadata->filter(function($value, $key) use($metadata)
{
return in_array($key, $metadata);
});
}
}
However this isn't updating my data with the new metadata, and when I dump the user data I'm still getting all my original metadata rather than just the username.
/**
* Fetch all the metadata for a user.
*
* #return objects
*/
public function metadata()
{
return $this->hasMany(UserMetadata::class);
}
/**
* Fetch the metadata as an attribute.
*
* #return array
*/
public function getMetadataAttribute()
{
return $this->metadata()->get()->flatMap(function($values)
{
return [$values['key'] => $values['value']];
});
}
/**
* Update the metadata attribute.
*
* #param varied $value The new metadata attribute.
* #return void
*/
public function setMetadataAttribute($value)
{
$this->attributes['metadata'] = $value;
}

Answer 1

Could you use the only() method at the collection level?
For example, you have your fields array from the URL. In this case it is only the one metadata field.
$fields = ['username'];
Then get all the users:
$users_all = User::all(); or however you wish to get the collection of users.
Then use the only() method to filter the results to just the fields you need:
$filtered = $users_all->only($fields);
Then return the filtered collection:
$filtered->all();
From: https://laravel.com/docs/5.5/collections#method-only