I've extended the default layered navigation in magento 2 so that filter parameters are added like so:
Where option ids are separated by an underscore, in the above example the product list displays all products with one or more of the 3 options selected.
This allows users to add more that one filter in each filterable category.
My question is how do i extend the way the advanced search builds the advanced search results query, so that it matches the way the layered navigation applies filters.
Currently, when I select multiple options from the advanced search and select search, it adds the query parameters in the form of an array,
I need to change this so that it matches the layered navigation query, can anyone help me on this?
I can see the action of the advanced form is returned from
\Magento\CatalogSearch\Block\Advanced\Form getSearchPostUrl(), and that this then retrieved the url from
Magento\Framework\View\Element\AbstractBlock getUrl($route = '', $params = ), which method should i override and how do i retrieve the params and define the structure of the query?
Any help on this would be greatly appreciated.