Unable to call and display a specific template from a controller

[KBW]

(Silverstripe Version:5.4)

Hi,

I am trying to have the template StudentHolder_Cities.ss called and displayed when the action Cities in the controller StudentHolderController.php is in the URL request.

I add the following four documents below:

(1) the code of StudentHolderController.php

(2) 21-06-2025 screenshot 1.png showing where StudentHolder_Cities.ss is placed in order to have it displayed (Two separate locations because of two separate attempts. Once without a namespace, once with a namespace)

(3) 21-06-2025 screenshot 2.png showing that the URL request works.

(4) 21-06-2025 screenshot 3.png showing that StudentHolder_Cities.ss is never called, regardless of where it is placed

StudentHolderController.php

<?php

# --> Attempt number 1: without the namespace

# --> Attempt number 2: with the namespace, targetting: 
#     \community\themes\simple\templates\Silverstripe\SSBootstrap\StudentHolder_Cities.ss

#namespace Silverstripe\SSBootstrap;

use SilverStripe\ORM\ArrayList;
use SilverStripe\View\ArrayData;
use SilverStripe\ORM\PaginatedList;
use SilverStripe\Control\HTTPRequest;

use SilverStripe\Dev\Backtrace;
use SilverStripe\Dev\Debug;

use PageController;

class StudentHolderController extends PageController
{
    private static $allowed_actions = [
		'Students',
		'Cities'
    ];

	private static $url_handlers = [
        'students' => 'Students',
		'cities/$ID' => 'Cities'
    ];

    protected $studentList;

    protected function init()
    {
        parent::init();

        $this->studentList = StudentPage::get()->filter([
								'ParentID' => $this->ID,
								'Active' => true,
								'Verified' => true,
							])->sort('Username ASC');

        
	}

	public function Students() {

		$studentsCitiesArrayList = ArrayList::create();

		$citiesArray =  [ '1' => 'Aachen',   '2' =>  'Berlin',   '3'  => 'Bonn',    '4' => 'Bremen',
                          '5' => 'Cologne',  '6' =>  'Dresden',  '7'  => 'Erfurt',  '8' =>'Frankfurt',
		                  '9' => 'Freiburg', '10' => 'Halle',    '11' => 'Hamburg', '12'=> 'Heidelberg',
                          '13' => 'Jena', '14' => 'Leipzig',  '15' => 'Magdeburg', '16' => 'Munich',
                          '17' => 'Stuttgart'
                        ];

		$studentsArray = array();

		foreach ($citiesArray as $k => $c) {
			$studentsArray[] = StudentPage::get()->filter(['Active' => 'Yes','Verified' => 'Yes','City' => $c]);
		}

		$studentsCountArray = array();

		foreach ($studentsArray as $s) {
			$studentsCountArray[] = $s->Count();
		}

		$studentsCitiesDataArray = array();

		foreach ($citiesArray as $k => $v) {

			$studentsCitiesDataArray['cityID'] = (int)$k;
			$studentsCitiesDataArray['cityName'] = $v;
			$studentsCitiesDataArray['studentsCount'] = $studentsCountArray[$k-1];

		}

        $studentsCitiesArrayList = new ArrayList;

		foreach ($studentsCitiesDataArray as $arr) {
			$studentsCitiesArrayList->push($arr);
		}
		return $studentsCitiesArrayList;

	}

	public function Cities(HTTPRequest $r)
    {

        $cityID = (int)$r->param('ID');

		$cityName = match($cityID){
			1 => "Aachen",
			2 => "Berlin",
			3 => "Bonn",
			4 => "Bremen",
			5 => "Cologne",
			6 => "Dresden",
			7 => "Erfurt",
			8 => "Frankfurt",
			9 => "Freiburg",
			10 => "Halle",
			11 => "Hamburg",
			12 => "Heidelberg",
			13 => "Jena",
			14 => "Leipzig",
			15 => "Magdeburg",
			16 => "Munich",
			17 => "Stuttgart",
			default => "unknown"
		};

        if($cityName == "unknown") {
            return $this->httpError(404,'The application cannot retrieve this city in the database.');
        }

        $this->studentList = $this->studentList->filter([
            'City' => $cityName
        ]);

        return [ 'SelectedCity' => $cityName ];
    }

    public function PaginatedStudents($num = 1)
    {
        return PaginatedList::create(
					$this->studentList,
					$this->getRequest()
				)->setPageLength($num);
    }
}

Could you please let me know where StudentHolder_Cities.ss has to be placed so that it can be accessed?

Thanks very much.

K.

[ntd]

@KBW

use PageController;

This is wrong and generates the warning “The use statement with non-compund…”. Just remove it.

I think the major problem is you are mixing lowercase and uppercase. You have everything with Cities (capitalized) in the code and in the filesystem, yet your URL (and consequentially your action) has cities (all lowercase).

[KBW]

In SS 4 online lesson tutorial (lesson 21, the last one), all actions start with a capital letter (see below).

In the documentation (v5), the template name also contains capital letters:

Why is that?

[ntd]

@KBW

… all actions start with a capital letter …

Those are generic methods, not actions.

Furthermore I never said capitalization is wrong: if the action is capitalized in your $allowed_actions, it should be capitalized in the URL too. In your specific case, you should have used http://localhost/community/abc/Cities/3

[KBW]

K.