Laravel Modify collection data

问题

I wonder if Laravel have any helper to modify a collection. What I need to do is to make a query with paginate() then check if the logged in users ID match the sender or reciever and based on that add a new value to the output:

$userId = Auth::guard('api')->user()->user_id;
      $allMessages = Conversation::join('users as sender', 'conversations.sender_id', '=', 'sender.user_id')
                                   ->join('users as reciver', 'conversations.recipient_id', '=', 'reciver.user_id')
                                   ->where('sender_id',$userId)->orWhere('recipient_id',$userId)
                                   ->orderBy('last_updated', 'desc')
                                   ->select('subject','sender_id','recipient_id','sender_unread','recipient_unread','last_updated','reciver.username as receivername','sender.username as sendername')
                                   ->paginate(20);

Now I want to do something like:

if (  $allMessages->sender_id == $userId ) {
    //add new value to output
    newField = $allMessages->sendername
} else {
    //add new value to output
    newField = $allMessages->receivername
}

Then send the data with the new value added

return response()->json(['messages' => $allMessages],200);

Is this possible?

回答1:

You're better off using the Collection class's built-in functions for this. For example, the map function would be perfect.

https://laravel.com/docs/5.3/collections#method-map

$allMessages = $allMessages->map(function ($message, $key) use($userId) {
    if ($message->sender_id == $userId) {
        $message->display_name = $message->receivername;
    } else {
        $message->display_name = $message->sendername;
    }

    return $message;
});

回答2:

Solved by adding:

foreach ($allMessages as $message) {
        if ($message->sender_id == $userId) {
            $message->display_name = $message->receivername;
        } else {
            $message->display_name = $message->sendername;
        }
      }

回答3:

As I don't know which Laravel version you're using, taking Laravel 5.2 let me give you a smarter way to deal with this (if I get your problem correctly).

You can use Laravel's LengthAwarePaginatior(API Docs).

Don't use paginate method when you are bulding your query, instead of that use simple get method to get simple collection.

$userId = Auth::guard('api')->user()->user_id;
  $allMessages = Conversation::join('users as sender', 'conversations.sender_id', '=', 'sender.user_id')
                               ->join('users as reciver', 'conversations.recipient_id', '=', 'reciver.user_id')
                               ->where('sender_id',$userId)->orWhere('recipient_id',$userId)
                               ->orderBy('last_updated', 'desc')
                               ->select('subject','sender_id','recipient_id','sender_unread','recipient_unread','last_updated','reciver.username as receivername','sender.username as sendername')
                               ->get();

Now you can populate extra items into that collection based on your certain conditions like this.

if ($allMessages->sender_id == $userId ) {
  // add new value to collection
} else {
  // add new value to collection
}

Now use LengthAwarePaginator, to convert that populated collection into a paginated collection.

$total_count = $allMessages->count();
$limit = 20;
$current_page = request()->get('page');
$options = [
    'path' => request()->url(),
    'query' => request()->query(),
];
$paginated_collection = new LengthAwarePaginator($allMessages, $total_count, $limit, $current_page, $options);

The variable $paginated_collection now can be used to be sent in response. Hope this helps you to deal with your problem.

来源：https://stackoverflow.com/questions/39751739/laravel-modify-collection-data

标签

php

laravel

mutators