How to update/replace a field in an ElasticSearch document using PHP?

Question

I want to update my Elasticsearch indexed document's field. In my case its the tags field. This is the code I currently have:

    // Index tags in the page document
    $es_client->update([
        'index'       => 'myappname',
        'type'        => 'page',
        'id'          => $page_id,
        'body'         => [
            'doc' => [
                'tags' => $tagsArray
            ]
        ]
    ]);

So, this would update my document by adding the tags array to it, but it won't remove the old tags. How can I make sure that the old tags get removed when I add the new tags?

I did look in the documentation, but as we all know, the Elasticsearch docs can be very confusing and all-over-the-place. Hence I am asking here after days of searching.

Any help or advice would be greatly appreciated.

Answer 1

Standard update behavior is to merge array/object fields as explained in the update API documentation .

...objects are merged together, existing scalar fields are overwritten and new fields are added.

So instead you would use a script to modify the document source directly. You can make it generic and thus cacheable, and pass in params for better performance. Php API documentation

// Index tags in the page document
$es_client->update([
   'index'       => 'myappname',
   'type'        => 'page',
   'id'          => $page_id,
   'body'        => [
      'script'      => 'ctx._source.tags=tags',
      'params'      => ['tags' => $tagsArray]
   ]    
]);