if/else Logic in Eloquent Query - if-statement

Question

I need to be able to query a model based on specific criteria within a route closure.
I have this route:
Route::get('courses/{category_slug}/{slug}', function($category_slug, $slug) {
$category = Category::where('slug', $category_slug)->first();
$course = Course::leftJoin('categories', 'categories.id', '=', 'courses.category_id')
->where('categories.slug', '=', $category_slug)
->where('courses.slug', '=', $slug)
->orWhere('categories.parent_id', '=', $category->id)
->where('categories.slug', '=', $slug)
->firstOrFail();
return View::make('courses.show')->with('course', $course);
});
This partially works but I need to be able to either use get() or firstOrFail() depending on whether the route points to a sub-category or an actual page.
It would also be nice to change the name of the variable based on this criteria, as well as the return value to use a different blade template.
Is this approach feasible? Thanks.
UPDATE: I almost have it working using:
http://paste.laravel.com/zod
The problem is, if the query for $sub_category doesn't return anything I get a model not found error.

Answer 1

OK, I got it working using:
Route::get('courses/{category_slug}/{slug}', function($category_slug, $slug) {
$category = Category::where('slug', $category_slug)->first();
$sub_category = Category::where('slug', $slug)->first();
if (!is_null($sub_category)) {
if ($sub_category->slug === $slug) {
$courses = Course::leftJoin('categories', 'categories.id', '=', 'courses.category_id')
->where('categories.parent_id', '=', $category->id)
->where('categories.slug', '=', $slug)
->get();
return View::make('courses.index')->with('courses', $courses);
}
} else {
$course = Course::leftJoin('categories', 'categories.id', '=', 'courses.category_id')
->where('categories.slug', '=', $category_slug)
->where('courses.slug', '=', $slug)
->firstOrfail();
return View::make('courses.show')->with('course', $course);
}
});
There is probably a better way, so if anyone can shed some light on it that would be great.

Answer 2

For anyone bumping in same problem, You can use the capability of the eloquent query builder to avoid duplication:
Route::get('courses/{category_slug}/{slug}', function($category_slug, $slug) {
$category = Category::where('slug', $category_slug)->first();
$sub_category = Category::where('slug', $slug)->first();
$course_query = Course::leftJoin('categories', 'categories.id', '=', 'courses.category_id')
->where('categories.parent_id', '=', $category->id)
->where('categories.slug', '=', $slug)
if (!is_null($sub_category)) {
if ($sub_category->slug === $slug) {
$courses = $course_query->get();
return View::make('courses.index')->with('courses', $courses);
}
} else {
$course = $course_query->firstOrfail();
return View::make('courses.show')->with('course', $course);
}
});
We create a common query $course_query that we can use below many times, avoiding duplication.
Note: $course_query declaration must have no get(), firstOrFail() or first()!