Laravel4: Checking many-to-many relationship attribute even when it does not exist
- by Simo A.
This is my first time with Laravel and also Stackoverflow...
I am developing a simple course management system. The main objects are User and Course, with a many-to-many relationship between them. The pivot table has an additional attribute, participant_role, which defines whether the user is a student or an instructor within that particular course.
class Course extends Eloquent {
public function users() {
return $this->belongsToMany('User')->withPivot('participant_role')->withTimestamps();
}
}
However, there is an additional role, system admin, which can be defined on the User object. And this brings me mucho headache. In my blade view I have the following:
@if ($course->pivot->participant_role == 'instructor') {
// do something here...
}
This works fine when the user has been assigned to that particular $course and there is an entry for this user-course combination in the pivot table.
However, the problem is the system administrator, who also should be able to access course details. The if-clause above gives Trying to get property of non-object error, apparently because there is no entry in the pivot table for system administrator (as the role is defined within the User object).
I could probably solve the problem by using some off-the-shelf bundle for handling role-based permissions. Or I could (but don't want to) do something like this with two internal if-clauses:
if (!empty($course->pivot)) {
if ($course->pivot->participant_role == 'instructor') {
// do something...
}
}
Other options (suggested in partially similar entries in Stackoverflow) would include 1) reading all the pivot table entries to an array, and use in_array to check if a role exists, or even 2) SQL left join to do this on database level.
However, ultimately I am looking for a compact one-line solution? Can I do anything similar to this, which unfortunately does not seem to work?
if (! empty ($course->pivot->participant_role == 'instructor') ) {
// do something...
}
The shorter the answer, the better :-). Thanks a lot!
