I have some model Task.
If current user has permission then he can see all tasks
return Task::all();
If current user does not have this permission then he can see only empty list
return Task::where('id', 0)->get();
Design is so that user must always get some result, but my functions work with data returned from Task::all() so I can not return empty array or empty Eloquent collection.
What should I do?
You don't want empty array, you don't want empty collection. Maybe you should change the design. Anyway, since you really want to pass an empty list of tasks, manually insert 1 o 2 tasks in the database as first tasks, so their IDs will always be 1 & 2. But leave everything else empty. Then you may always return those 2
return Task::whereIn('id', [1,2])->get();
My suggestion, is to actually fix the design to expect empty object, so you could do something like
return '';
One option would be to return a newly created Task object in an array if the JSON schema has to match exactly. It would look like so:
$emptyTask = new Task();
return [$emptyTask]
Related
I have a collection of "Tickets", using the random collection utility method I select one from the list. The "Tickets" collection should now remove (or forget) that randomly selected ticket so I can further process that collection. Using the forget method doesn't appear to do what is described in the documentation or (more likely I'm missing something).
Can someone spot whats wrong in my code?
$tickets = Tickets::all();
$total_winners = 5;
$selected_tickets = $tickets->random($total_winners);
$jackpot_winner = $selected_tickets->random();
$selected_tickets->forget($jackpot_winner->id); // this line should remove the $jackpot_winner
When I print the contents of $selected_tickets on lines 3 and lines 5, they have the exact same items, including the $jackpot_winner.
Forget function uses the collection key not the id from the model. To achieve what you want you may use this method:
$selected_tickets = $selected_tickets->except($jackpot_winner->id);
https://laravel.com/docs/8.x/collections#method-except
I have an array of string, and want to filter out a particular string after some operation. But, it seems I am doing something wrong there.
this.displayUser.followers.filter(userId=>userId !== this.loggedUser.userid);
Here, followers is an array of string -> string[] and upon some action (say, unfollow); I want to remove the logged user's id from the displayed user's followers list.
However, this filter operation does not seem to work.
On the other hand I tried using splice which is working perfectly fine.
this.displayUser.followers.splice(
this.displayUser.followers.findIndex(userId=>userId === this.loggedUser.userid)
,1);
I am unable to understand what am I doing wrong in the first approach?
Array.filter does not change the array it performs its action on, but returns a new array with values that passed the condition.
In order to use .filter and have the result saved, you can do:
this.displayUser.followers = this.displayUser.followers.filter((userId) => userId !== this.loggedUser.userid);
This will remove all entries where userId === loggedUser.userid.
.splice on the other hand manipulates the array it performs its actions on, hence you will immediately see the results as expected.
I have some instances where a eloquent is resulting an single array not a collection. Although dd shows it as a collection with a single entry.
For example I have a query in a controller:
$pg = Page::with('getPanels')->where('slug',$slug)->get();
This will return a single result and works fine, so I pass this to a blade template. My complete function is
$pg = Page::with('getPanels')->where('slug',$slug)->get();
return view('front.page',['pg' => $pg]);
As soon as he template is brought in it will fall over at
if (!is_null($pg->headImage))
{$img = asset('images/pages')."/".$pg->headImage;}
and I will get
Property [headImage] does not exist on this collection instance.
If I change the line to
if (!is_null($pg[0]['headImage']))
it will continue OK. This is of course a pain as I would much rather use $pg->headImage.
Can someone enlighten me please?
I have sorted this and I hope it will help other people.
If I use
$pg = Page::with('getPanels')->where('slug',$slug)->first();
it will be just one result (naturally) and therefore
$pg->headImage
will fail as it wants
$pg[0]['headImage']
but if I change the eloquent instead of get(0 to first() (still just one result)
$pg = Page::with('getPanels')->where('slug',$slug)->first();
I can use $pg->headImage or what field I want.
I want to get alternative products pictures.
dd($alternativeProduct->pictures);
When die and dump i get this result.
I need to get only the picture which is main. If main equals to 1. It is main picture.
When I write
dd($alternativeProduct->pictures->where('main', 1))
I got an empty array.
Here is my relation with Product and Picture relation
public function pictures(){
return $this->hasMany('App\Models\ProductPicture');
}
What can i do ?
The where method in a collection has three parameters: $key, $value and $strict, the last one defaults to true if not passed when calling the method. When $strict is true the comparison is done via === which does not do type coercion, meaning "1" === 1 is false.
From your dump data, I can see that "main" => "1" which means it's a string and you're passing an integer 1 to the where method, resulting in what I described above as a false condition and returning an empty result set. You can fix that by disabling strict comparison:
$alternativeProduct->pictures->where('main', 1, false);
// or the equivalent helper whereLoose
$alternativeProduct->pictures->whereLoose('main', 1);
Or passing a string as the value:
$alternativeProduct->pictures->where('main', "1");
That being said, if that's the only place you're using that collection in that request's context, I suggest that you filter the results at the database level, not after they are fetched, like so:
$alternativeProduct->pictures()->where('main', 1)->get();
Accessing the relations as a method ->pictures(), instead of as a property ->pictures, will return a Query Builder instance that allows you to add conditions to the database query and only fetch the actual items you need from the database, instead of fetching them all and filtering them out afterwards.
You may want to use whereLoose instead:
dd($alternativeProduct->pictures->whereLoose('main', 1))
From the Laravel docs:
The where method uses strict comparisons when checking item values. Use the whereLoose method to filter using "loose" comparisons.
I am new to laravel and confused about some query methods.
find($id) is useful and returns a nice array, but sometimes I need to select by other fields rather than id.
The Laravel document said I could use where('field', '=', 'value') and return a bunch of data, which is fine.
What I can't understand is why I need to add ->first() every time, even if I am pretty sure there is only one single row matches the query.
It goes like this:
$query->where(..)->orderBy(..)->limit(..) etc.
// you can chain the methods as you like, and finally you need one of:
->get($columns); // returns Eloquent Collection of Models or array of stdObjects
->first($columns); // returns single row (Eloquent Model or stdClass)
->find($id); // returns single row (Eloquent Model or stdClass)
->find($ids); // returns Eloquent Collection
// those are examples, there are many more like firstOrFail, findMany etc, check the api
$columns is an array of fields to retrieve, default array('*')
$id is a single primary key value
$ids is an array of PKs, this works in find method only for Eloquent Builder
// or aggregate functions:
->count()
->avg()
->aggregate()
// just examples here too
So the method depends on what you want to retrieve (array/collection or single object)
Also the return objects depend on the builder you are using (Eloquent Builder or Query Builder):
User::get(); // Eloquent Colleciton
DB::table('users')->get(); // array of stdObjects
even if I am pretty sure there is only one single row matches the query.
Well Laravel cant read your mind - so you need to tell it what you want to do.
You can do either
User::where('field', '=', 'value')->get()
Which will return all objects that match that search. Sometimes it might be one, but sometimes it might be 2 or 3...
If you are sure there is only one (or you only want the first) you can do
User::where('field', '=', 'value')->first()
get() returns an array of objects (multiple rows)
while
first() returns a single object (a row)
You can of course use get() when you know it will return only one row, but you need to keep that in mind when addressing the result:
using get()
$rez = \DB::table('table')->where('sec_id','=','5')->get();
//will return one row in an array with one item, but will be addressed as:
$myfieldvalue = $rez[0]->fieldname;
using first()
$rez = \DB::table('table')->where('sec_id','=','5')->first();
// will also return one row but without the array, so
$myfieldvalue = $rez->fieldname;
So it depends on how you want to access the result of the query: as an object or as an array, and also depends on what "you know" the query will return.
first() is the equivalent of LIMIT 1 at the end of your SELECT statement. Even if your query would return multiple rows, if you use first() it will only return the first row