Multiple templates for one page, like PHP traits, or "granular" templates?

[martin]

I'm wondering if there's a clean way I can implement a granular templates system for a web application I want to build. By granular templates, I mean that you can apply more than one template to a page, and all fields from all applied templates will be made available.

I want something similar to this:

House (page) implements Basic-House, Garage, Garden (templates)

or

Vehicle (page) implements Basic-Car, Diesel-Engine, Turbo-Engine, Four-Wheel-Drive (templates)

The simple (already available) option is to use the page's children as the "granules", but it means having 2-4 children per item just to implement extra fields. I would rather some sort of inline solution.

Thanks in advance for any suggestions.

[LostKobrakai]

There's currently no way to implement this. Each template does have a single fixed set of fields. That is at least the answer to the backend structure. What you can do is provide a own php class (subclass of Page) to the "parent" entity. This class could then populate itself at runtime with the fields of those childpages you mentioned. This way you could at least maintain the structure in your code. The option to set such a class is in the template settings if you enable advanced mode. Maybe this could even be done with hooking the Page class, and without using the advanced mode settings. 

[horst]

I mean that you can apply more than one template to a page, and all fields from all applied templates will be made available.

Is it needed for the Backend Editmode? What's about to simply have one template with some fieldsets, each fieldset contains a few fields (those you mentioned in your subtemplates) and the visibility of the fieldsets are bound through checkboxes and the onlyShowIf settings for templates?

| Select granule Subtemplates:                                                                |
|                                                                                             |
| [ ] use Basic-Car | [ ] use Diesel-Engine | [ ] use Turbo-Engine | [ ] use Four-Wheel-Drive |
|                                                                                             |

| Select granule Subtemplates:                                                                |
|                                                                                             |
| [x] use Basic-Car | [ ] use Diesel-Engine | [ ] use Turbo-Engine | [ ] use Four-Wheel-Drive |
|                                                                                             |
|--- Basic car -------------------------------------------------------------------------------|
|                                                                                             |
|  BC_textfield_1            BC_ceckbox_1            ...                                      |
|                                                                                             |
|---------------------------------------------------------------------------------------------|

| Select granule Subtemplates:                                                                |
|                                                                                             |
| [x] use Basic-Car | [ ] use Diesel-Engine | [ ] use Turbo-Engine | [x] use Four-Wheel-Drive |
|                                                                                             |
|--- Basic car -------------------------------------------------------------------------------|
|                                                                                             |
|  BC_textfield_1            BC_ceckbox_1            ...                                      |
|                                                                                             |
|---------------------------------------------------------------------------------------------|
|--- Four-Wheel-Drive ------------------------------------------------------------------------|
|                                                                                             |
|  FWD_textfield_1            FWD_ceckbox_1          ....                                     |
|                                                                                             |
|---------------------------------------------------------------------------------------------|

-

Pseudocode is like: only show Fieldset_BasicCar if Checkbox_BC is checked

[Martijn Geerts]

It is possible to swap the template file on runtime so that a page can have multiple template files. Maybe this is sufficient for you.

This is possible with the Module FieldtypeSelectFile. You have to check the checkbox "Change Page Template" in the module settings and select the file to render in a page.

[martin]

There's currently no way to implement this. Each template does have a single fixed set of fields. That is at least the answer to the backend structure. What you can do is provide a own php class (subclass of Page) to the "parent" entity. This class could then populate itself at runtime with the fields of those childpages you mentioned. This way you could at least maintain the structure in your code. The option to set such a class is in the template settings if you enable advanced mode. Maybe this could even be done with hooking the Page class, and without using the advanced mode settings. 

Yes, I thought as much. My backup plan was just to do it in the template for the parent page, selecting all children and find out details about their template and fieldgroups.

Is it needed for the Backend Editmode? What's about to simply have one template with some fieldsets, each fieldset contains a few fields (those you mentioned in your subtemplates) and the visibility of the fieldsets are bound through checkboxes and the onlyShowIf settings for templates?

| Select granule Subtemplates:                                                                |
|                                                                                             |
| [ ] use Basic-Car | [ ] use Diesel-Engine | [ ] use Turbo-Engine | [ ] use Four-Wheel-Drive |
|                                                                                             |

| Select granule Subtemplates:                                                                |
|                                                                                             |
| [x] use Basic-Car | [ ] use Diesel-Engine | [ ] use Turbo-Engine | [ ] use Four-Wheel-Drive |
|                                                                                             |
|--- Basic car -------------------------------------------------------------------------------|
|                                                                                             |
|  BC_textfield_1            BC_ceckbox_1            ...                                      |
|                                                                                             |
|---------------------------------------------------------------------------------------------|

| Select granule Subtemplates:                                                                |
|                                                                                             |
| [x] use Basic-Car | [ ] use Diesel-Engine | [ ] use Turbo-Engine | [x] use Four-Wheel-Drive |
|                                                                                             |
|--- Basic car -------------------------------------------------------------------------------|
|                                                                                             |
|  BC_textfield_1            BC_ceckbox_1            ...                                      |
|                                                                                             |
|---------------------------------------------------------------------------------------------|
|--- Four-Wheel-Drive ------------------------------------------------------------------------|
|                                                                                             |
|  FWD_textfield_1            FWD_ceckbox_1          ....                                     |
|                                                                                             |
|---------------------------------------------------------------------------------------------|

-

Pseudocode is like: only show Fieldset_BasicCar if Checkbox_BC is checked

This is an interesting option... and within 20 minutes I have it working like this. PW continues to impress! I've even managed to use the fieldsets in my PHP template to visually group and perform logic on those granules.

Still needs some more testing but I think it'll work. Thank you

[LostKobrakai]

This is an interesting option... and within 20 minutes I have it working like this. PW continues to impress!

The only issue I'd have with it, is that you can't easily reuse fixed groups of fields. You have to set this up for each template on it's own or implement a custom setup process via api. But still better than nothing.

[horst]

The only issue I'd have with it, is that you can't easily reuse fixed groups of fields. You have to set this up for each template on it's own or implement a custom setup process via api. But still better than nothing.

Na, there is also PageTable and PageTableExtended available.

[martin]

The only issue I'd have with it, is that you can't easily reuse fixed groups of fields. You have to set this up for each template on it's own or implement a custom setup process via api. But still better than nothing.

I only have one template and will never need more. The app has a very specific requirement to fill. But yes, it's not perfect.

[LostKobrakai]

@horst

I know that and I actually meant reusing groups of fields in different templates not in a single one. Just like the example in the entry post with have multiple classes which implement the same base classes to share sets of properties / methods.

[martin]

The one problem I have now is that, although I can find out which fields are in each fieldset from the template, I don't have any direct link between the fields and the granule checkbox.

Can I access the "show if" value in my PHP template?

[LostKobrakai]

You can't, you need to check that manually. Inputfield dependencies are only evaluated on the frontend by javascript.

[horst]

You can't, you need to check that manually. Inputfield dependencies are only evaluated on the frontend by javascript.

But I think the checkbox states are saved with the pages, or not?

if ($pages->checkbox_bc) { // the fields bundled to "Basic Car" are in use

You once have to manually note which fields belong to which subtemplate, (will be good if the fields will not grow in the future)

or you stick with a naming scheme and iterate over all template fields to get that information. Maybe not very elegant or high dynamcly, but a fast way to get the job done.

EDIT:

$subtemplateIds = array('bc'=>aray(), 'fwd'=>array());

foreach($page->template->fields as $field) {
    foreach(array_keys($subtemplateIds) as $k) {
        $fn = $field->name;
        $len = strlen($k) + 1;
        if (substr($fn, 0, $len) == $k . '_') {
            $subtemplateIds[$k][] = $fn;
        }
    }
}

// later on you can check like:
if ($page->checkbox_bc) {
    // use also all fields from $subtemplateIds['bc']
}

(written in browser, be careful   )

Edited March 17, 2015 by horst
added example code

[martin]

But I think the checkbox states are saved with the pages, or not?

if ($pages->checkbox_bc) { // the fields bundled to "Basic Car" are in use

You once have to manually note which fields belong to which subtemplate, (will be good if the fields will not grow in the future)

or you stick with a naming scheme and iterate over all template fields to get that information. Maybe not very elegant or high dynamcly, but a fast way to get the job done.

Schema changes should be extremely rare, but hard-coding the relationships still doesn't sit well with me. I suppose I'll have to go with prefixes on fields to decide their group.

[bernhard]

sorry for being not exactly on-topic but how can i close a fieldset? never used them and wanted to try it reading this thread...

[martin]

When you create the fieldset, it creates two fields. One is (fieldsetname) and one is (fieldsetname)_END.

You put both of those in the template.

[bernhard]

great! should have noticed them earlier thank you