Laravel 5 Read Only View Model with polymorphic Relationship

user_2911359 0
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Sometimes we use MySql Views to organize related tables to make it easier to search and sort. For example if you have Posts with a Status, and a Source.

Post
    subject
    body
    source_id
    status_id

Status
    id
    label
    other_field

Source
    id
    label
    other_field


View
   create view read_only_posts as
   SELECT statuses.label as status, sources.label as source, posts.*
   from posts
   left join statuses on statuses.id = posts.status_id
   left join sources on sources.id = posts.source_id

Then we have the Post model and an extra model:

// Post.php
class Post extends Model
{
    //
}

// ReadOnlyPost.php
class ReadOnlyPost extends Post
{
    protected $table = 'read_only_posts';
}

This is nice because now you can directly sort or filter on Status or Source as a string not the id's. You can also include the 'other_field'.

But we have a problem that I need help with. If you have a polymorphic many-to-many relationship on Posts, I can't get it to work on the read only version. For example if you have polymorphic tags:

// Post.php Model
public function tags()
{
    return $this->morphToMany(Tag::class, 'taggable');
}

The problem is when you filter a post (using the read only model) with a specific tag you get sql like this:

select count(*) as aggregate from read_only_posts where exists (select * from tags inner join taggables on tags.id = taggables.taggable_id where read_only_posts.id = taggables.taggable_type and taggables.taggable_type = 'read_only_posts' and label = 'test')

As you can see the problem is the taggables.taggable_type = 'read_only_posts'.

I can't find a way to override the morph type for a model. (I am on laravel 5.4 and the MorphClass isn't there anymore). The morph map is an associative array so you can't do this:

// AppServiceProvider
public function boot()
{
    Relation::morphMap([
        'posts' => Post::class,
        'posts' => ReadOnlyPost::class, <--- Can't do this

My stupid fix is when I attach a tag to a post I also attach it to ready_only_posts, which is kind of a mess.

Anyone else uses Views for read only models? Anyone have a better way to overriding the many to many polymorphic type for a specific model?

laravel-5 laravel polymorphism mysql
1 Answers

Looking at the code, I believe this might work.

class ReadOnlyPost extends Posts
{
    public function getMorphClass() {
         return 'posts';
    }
}

In theory you should need to have the Posts model/table listed in the morph map, since the system will auto generate the type of "posts" for it based on naming.

user_9292220
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