Why do I get an error related to a controller when I created a custom module?

Question

I created custom module following the Creating a custom module on Drupal tutorial.

The teacher of this tutorial demonstrated how you can create a custom module that displays on the page Hello world. But I have a slightly more difficult task. I need to create a custom module that will display the weather on the page, receiving data using API, like this.

17.52
1016
London

What I did.

I created the weather.info.yml file.

name: Weather module              
description: Weather module 
core: 8.x                               
type: module                        
package: Weather  

I created the weather.routing.yml file.

weather.weather_page:                               
  path: '/weather'
  defaults:                                                       
    _controller: '\Drupal\weather\Controller\WeatherPage::getWeather'                          
  requirements:                                        
     _permission: 'access content'  

In src/Controller, I created the WeatherPage.php file.

namespace Drupal\weather\Controller;        

class WeatherPage
{
  public function getWeather($city)
  {
    $response = file_get_contents('http://api.openweathermap.org/data/2.5/weather?q='.$city.',uk&appid=32ae008b1c7259324aa50450687fabf5&units=metric');
    $jsn = json_decode($response);
    
    echo $jsn->main->temp; 
    echo '<br>'; 
    echo $jsn->main->pressure; 
    echo '<br>'; 
    echo $city; 
    
  }    
}

$class = new WeatherPage();
$class->getWeather('London');


?>

I get an error related to the controller.

How do I fix this error?

P.S. One forum user writes that the problem may be due to:

• The controller must return the array
• No code should be behind the class

I'm a Drupal newbie.

Answer 1

You need to add the parameter to the path. Change this:

path: '/weather'

To this:

path: '/weather/{city}'

Note that the parameter name {city} must be expressed as the parameter $city in your callback (which you've done). If you for exampled changed the function definition to getWeather($c), you would get an error.

Also, you need to remove this code:

$class = new WeatherPage();
$class->getWeather('London');


?>

And finally, you'll need to return a render array. Change this:

echo $jsn->main->temp; 

To this:

return [
  '#markup' => $jsn->main->temp,
];