18. Troubleshooting

18.1. The toString method

Sometimes the bundle needs to display your model objects, in order to do it, objects are converted to string by using the __toString magic method. Take care to never return anything else than a string in this method. For example, if your method looks like that:

// src/Entity/Post.php

class Post
{
    public function __toString()
    {
        return $this->getTitle();
    }
}

You cannot be sure your object will always have a title when the bundle will want to convert it to a string. So in order to avoid any fatal error, you must return an empty string (or anything you prefer) for when the title is missing, like this:

// src/Entity/Post.php

class Post
{
    public function __toString()
    {
        return $this->getTitle() ?: '';
    }
}

18.2. Large filters and long URLs problem

If you will try to add hundreds of filters to a single admin class, you will get a problem - very long generated filter form URL. In most cases you will get server response like Error 400 Bad Request OR Error 414 Request-URI Too Long. According to a StackOverflow discussion “safe” URL length is around 2000 characters. You can fix this issue by adding a small JQuery piece of code to your edit template:

$(function() {
    // Add class 'had-value-on-load' to inputs/selects with values.
    $(".sonata-filter-form input").add(".sonata-filter-form select").each(function(){
        if($(this).val()) {
            $(this).addClass('had-value-on-load');
        }
    });

    // REMOVE ALL EMPTY INPUT FROM FILTER FORM (except inputs, which has class 'had-value-on-load')
    $(".sonata-filter-form").submit(function() {
        $(".sonata-filter-form input").add(".sonata-filter-form select").each(function(){
            if(!$(this).val() && !$(this).hasClass('had-value-on-load')) {
                $(this).remove()
            };
        });
    });
});