Benjamin Listwon

When I was first building out the code for this blog, I gave some thought to how to add tagging. The Laravel Docs actually use tagging as an example of polymorphic relations. But then, over on his new jam Makers Clique, Scrivs mentioned a package called Cartalyst Tags which looked like it ticked all the boxes.

After following the installation instructions, I added a tags field to my post forms:

/resources/views/post/create.blade.php

<p>
    {{ Form::label('tags', 'Tags (separate with comma)') }}
    {{ Form::text('tags') }}
</p>

(I’m using the Laravel Collective Form & HTML package here. More on that below, and in another post.

Displaying the tag list on a post was pretty easy as well:

/resources/views/post/show.blade.php

@if ($post->tags)
    <ul class="tags">
    @foreach ($post->tags as $tag)
        <li><a href="/tag/{{ $tag->slug }}">{{ $tag->name }}</a></li>
    @endforeach
    </ul>
@endif

Then I tweaked my store and update methods and voilà, my posts were taggable.

Getting The Tags For Update

So, I hit a huge brick wall when I wanted to retrieve the tags in my edit form. I’ll keep this as brief as I can.

Calling $post->tags will give you a collection of tag objects. This can be useful if you are going to work with them in code, but is not so great for display in a template:

[{
    "id":2,
    "namespace":"App\\Database\\Models\\Post",
    "slug":"laravel",
    "name":"Laravel",
    "count":2,
    "pivot":{"taggable_id":1,"tag_id":2}
}, ...]

Of course, you can iterate over that array, pulling out items by key if all you need is display. Trouble is, because I use the Form package, I cannot control the output so easily.

Form objects are bound to a model—in this case Post—so references to model properties will invoke the appropriate accessor. In the case of tags, it will use the $post->tags, which returns the above, and places it in the value attribute. Blech!

/resources/views/post/edit.blade.php

{{ Form::model($post, ['method' => 'PUT', 
        'action' => ['PostController@update', $post->id]] ) }}
...
<p>
   {{ Form::label('tags', 'Tags (separate with comma)') }}
   {{ Form::text('tags') }}
</p>
...
{{ Form::close() }}

Basically, I wanted the value of tags to be something like “Tag, Tag 2, Another Tag” when it was being placed back into the text field on my edit form.

Things I tried:

1. Decorate the results of $post->tags on the way back to the template. For reasons I didn’t dig too much further into, and because $post->tags retrieves a relationship, it is expected to return an object of type Relation. Mucking with it at all yields this error: Relationship method must return an object of type Illuminate\Database\Eloquent\ Relations\Relation

2. Custom Accessors looked like the way to go for a while, but formTagAttribute will never get called, because tags is not an attribute of the model, it is a relationship.

3. I tried to make a custom component to render the form field correctly, but that just kicked the above can down the road.

4. I also tried adding another accessor and a custom property to my Post model, but they all continued to run into the Relation issue above.

In the end, here’s what worked:

/App/Database/Models/Post.php

public function tagList() 
{
    $tags = $this->tags;
    $tagList = array();
    foreach ($tags as $tag) {
        array_push($tagList, $tag->name);
    }
    return implode(', ', $tagList);
}

Which I use like so:

{{ Form::label(‘tags’, ‘Tags (separate with comma)’) }} {{ Form::text(‘tags’, $post->tagList()) }}

Unfortunately, I don’t get the automatic handling of old('tags'), then fall through to the above, then fall through to blank. But, I think that can be added to a custom component, which I will throw together now that I have the way to retrieve the data I need.

Displaying Posts With Tag XYZ

You may have noticed that the link I use to get all posts with a given tag looks like this <a href="/tag/{{ $tag->slug }}">{{ $tag->name }}</a>.

The $tag->slug uses Laravel’s default slug generator, so a tag like “Dogs and Cats” will get sluggified as “dogs-and-cats”.

One thing the documentation doesn’t make clear is that you MUST use the slug to retrieve items tagged with a given tag. Here’s the example:

$products = Product::whereTag(‘foo, bar’)->get();

From that, it is impossible to tell if ‘foo’ and ‘bar’ represent tag->name or tag->slug properties.

So, your controller method for this will look something like:

/App/Http/Controllers/TagController.php

public function show($slug)
{
    $posts = Post::whereTag($slug)->orderBy('created_at', 'desc')->get();
    $tag = Tag::where('slug', $slug)->first();
    return view('tag.show', array_merge(compact('posts', 'tag')));
}

Note that I am also fetching the tag itself here, just so I can refer to it outside the scope of any given post in my template.

Displaying All Tags

The final issue I ran up against was retrieving all the tags. While the docs say you can use the allTags() method to retrieve all the tags for a given domain, it failed to return any results no matter what I did.

Having blown way too much time on the above, I opted to simply add my own model, so I could query the tags table myself.

/App/Database/Models/Tag.php

<?php

namespace App\Database\Models;

use Illuminate\Database\Eloquent\Model;

class Tag extends Model
{

    /**
     * The database table used by the model.
     *
     * @var string
     */
    protected $table = 'tags';

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = ['namespace', 'name', 'slug', 'count'];

}

With that in place, I simply did the following:

/App/Http/Controllers/TagController.php

public function index()
{
    $tags = Tag::get();
    return view('tag.index', array_merge(compact('tags')));
}

Later, I will add queries to fetch by domain, etc.

Hope the above can help someone. Cheers!