How to utilize Laravel Cache in API? - laravel

Question

In my company we have a three user roles: admin, physician and client. All of them can view one of the records table where we have about 1 million rows and we are in need of caching the results from database.
I've read 10's of posts on Stack and else but I am still trying to figure out the proper way of how to caching.
What I've read is that the proper way is to cache per page, so I cache page 1, page 2 etc based on user page selection. This all works fine.
BUT each user role sees different datasets with different filters selected by them and this is where the problem starts. I cache the results and then filtering the paginated 10 rows seems kind of redundant.
I don't know if I should cache results for each user role with the selected parameters?
Or should I cache all the results first, then load the needed relationships and filter the collection with the parameters from user and then create pagination?
Or shouldn't I be using cache at all in this example and just use simple pagination?
// Set the cache time
$time_in_minutes = 5 * 60;
// Request page and if not set then default page is 1
$page = $paginationObject['page'];
// Set items per page
$per_page = $paginationObject['perpage'] ? $paginationObject['perpage'] : 10;
// Set the cache key based on country
$cache_key = "l04ax_pct_dispensing_forms_{$request->get('country')}_page_{$page}_per_page_$per_page";
// Cache::forget($cache_key);
// Set base query for results
$baseQuery = $this->model->with(['details', 'patient']);
// Assign appropriate relations based on user role
if (Auth::user()->isPhysician()) {
$baseQuery->physicianData();
}
else if (Auth::user()->isManufacturer()) {
$baseQuery->manufacturerData();
}
else if (Auth::user()->isSuperAdmin() || Auth::user()->isAdmin()) {
$baseQuery->adminData();
}
//--------------------------------------
// Add filtering params from request
// -------------------------------------
$baseQuery->when($request->has('atc_code'), function ($query) use ($request) {
if ($request->get('atc_code') === NULL) {
throw new RequestParameterEmpty('atc_code');
}
$query->whereHas('details', function ($subQuery) use ($request) {
$subQuery->where('atc_code', $request['atc_code']);
});
})
->when($request->has('id'), function ($query) use ($request) {
if ($request->get('id') === NULL) {
throw new RequestParameterEmpty('id');
}
$query->where('l04ax_dispensing_forms.id', $request['id']);
})
->when($request->has('pct_patients_hematology_id'), function ($query) use ($request) {
if ($request->get('patient_id') === NULL) {
throw new RequestParameterEmpty('patient_id');
}
$query->where('patient_id', $request['patient_id']);
})
->when($request->has('physician_id'), function ($query) use ($request) {
if ($request->get('physician_id') === NULL) {
throw new RequestParameterEmpty('physician_id');
}
$query->where('physician_id', $request['physician_id']);
})
->when($request->has('date'), function ($query) use ($request) {
if ($request->get('date') === NULL) {
throw new RequestParameterEmpty('date');
}
$query->whereDate('created_at', Carbon::parse($request->get('date'))->toDateString());
})
->when($request->has('deleted'), function ($query) use ($request) {
if ($request->get('only_deleted') === NULL) {
throw new RequestParameterEmpty('only_deleted');
}
$query->onlyTrashed();
})
->when($request->has('withTrashed'), function ($query) use ($request) {
if ($request->get('withTrashed') === NULL) {
throw new RequestParameterEmpty('withTrashed');
}
$query->withTrashed();
});
// Remember results per page into cache
return Cache::remember($cache_key, $time_in_minutes, function () use ($baseQuery, $per_page, $page) {
return new L0axPctDispensingFormsCollection($baseQuery->paginate($per_page, ['*'], 'page', $page));
});
In this example the results are cached per page, but when different user logs in, then the results are wrong.
What would be the best way to approach this?

Answer 1

I wouldn't recommend caching this because of the problem you have already encountered. Caching is massively helpful in some areas (e.g. for reference data like a persistent list of countries or currencies), but for user-specific data I would avoid.
If you really did want to cache you could use cache tagging (supported by redis using the phpredis driver only) to tag by user id. However, as mentioned, I wouldn't recommend in this scenario!
If your desire to cache is driven by the scenario where your pages are loading slowly I would recommend installing Laravel Debugbar, and checking to see how many queries your api calls are generating.
If you find a single api call is generating more queries than the number of records you are loading, then you likely are having the 'n + 1 problem' and need to eager load any nested relationships rather than call them in your resource.
P.s You can immediately reduce the number of queries generated by this controller method by only calling Auth::user() once. e.g. $user = Auth::user() and then $user->isSuperAdmin();