[TYPO3-shop] commerce - choosing from multiple parent categories with TS rootline object

[Amiran Chyb]

Hi there

I've chosen tx commerce because of flexibility it provides with nested  
categories and possibility of multiple parent categories.

Let me explain how I wanted to use this feature, it will be then easier to  
explain my problem on a example.

I'm setting up gallery website. Gallery's products will have some 1/2  
level categories, like

jewellery
    -rings
       -product1
       -product2
    -necklaces
       -product3

glass
    -product4



additionaly I'd like to browse products by their author (maker). so I've  
added additional Authors categories subtree


Authors
    -author1
       -product1
       -product3
    -author2
       -product2
    -author3
       -product4

Product Types
	-jewellery
	   -rings
	      -product1
	      -product2
	   -necklaces
	      -product3
	-glass
	   -product4


with this setup, when I'm adding new product I can set 2 parent categories  
for it, one from Product Types subtree, and one from Authors subtree.


On a page, I can have 2 menus: for each subtree (btw. for Product Types  
subtree I use regular page structure, and on each page I insert products  
categories plugin with appropriate category selected just to have  
possibility of using normal page tree menu, since it allows me to get  
EXPALL functionality which categories menu lacks at the moment).

And now, to the point:
Depending on which subtree FE user is browsing he will be aware of this  
subtree's categories. So, if he's choosing jewellery-rings he will see  
product1 and product2, but he won't be able to see authors of those  
products (in this case: author1).


To achieve this functionality we would have to use Rootline navigation  
which can handle multiple parents.
It would get 2 parameters: current category ID/product ID and a target  
root category.

It would then search recursively parent categories of current cat/product  
until it would find given  Root category ID (in a 2nd parameter). Then, it  
would return the UID for this particular path that managed to get bak to  
given Root category.

so, for example, in pseudo ts

1 = commerce_rootline
1.rootCategory = 2


given 2 is uid of Authors ccategory and we are on Product  
Types-jewellery-rings-product1 page, the function called by rootline would  
start searching path beginning by parent categories of current product (in  
case of PRODUCT1 it would be 2 parent categories - 'rings' and 'author1'):



product1-rings-jewellery-product types-categories root // no  
rootCategory=2 found here

and second one:

product1-author1-authors // authors has UID=2, so the search stops here


and hence it would return: authors-author1-product

 from which I could choose with TS only lewvel with AUTHOR1 information and  
display it in some TS Object Path field with Templa Voila (or even better,  
I could use it inside of product list template, so ich product in a list  
would contain additional field 'Author').


Know, let's look at the current implementation.
I've scanned the current navigation code, and this is what I know:

current CommerceRootline function in \lib\class.tx_commerce_navigation.php  
already calls:

getCategoryRootlineforTS($this->gpVars['catUid'],$this->category);

this function looks fine for single parent category model, but is unable  
to search for multiple parent categories for 2 reasons:

1) as a starting point it chooses gpVars['catUid']. And CatUID gpvar for  
currently selected product depends only on our browsing history (which  
category were we browsing on a previous page: author1 or rings), so it  
doesn't really checks the db for products parent categories. also, it  
wouldn't work if we would like to insert this rootline for each product on  
a product listing page, since it would use the same CatUID for each of  
them (the one from GET vars).


2) getCategoryRootlineforTS doesn't check for parent categories, it just  
gets

$CategoryObject->parent_category_uid

so it's just a single parent.

I'm not sure which one parent would show up if we have multiple parents,  
but I guess it depends on a way of adding new product (order of parent  
categories in commerce module or something like that).

moreover, class.tx_commerce_category which $CategoryObject instantiates  
doesn't have getParentCategories() member too.

Actually the equivalent DAO class class.tx_commerce_db_category has this  
method ( getParentCategories() ) for retrieving parents from DB, so it  
would be trivial to add it to tx_commerce_category.


Then it would be possible to change getCategoryRootlineforTS to search in  
a multiple parents paths.



I don't know whether I should start writing it, or choose some other way,  
so my questions:
is this feature planned, was it planned briefly in a way I've described it  
and is there any other way to achieve it?

even if it would work like that I think it wouldn't be trivial to insert  
this parent information to each product in a products list (as opposed to  
single product description) - would I have to add to product listing  
pluigin/template additional marker which would insert data based on some  
additional plugin TS configuration?




thanks a lot

greets
Amiran Chyb