Question

I’m reading opencart php source code, and I can’t figure this out.
Please take a look at function rewrite() at “$url = $rewrite->rewrite($url);”

<?php
class Url {
    private $url;
    private $rewrite = array();

    public function link($route, $args = '', $connection = 'NONSSL') {
    ....

        foreach ($this->rewrite as $rewrite) {
            $url = $rewrite->rewrite($url);
        }
        return $url;
    }

public function addRewrite($rewrite) {
    $this->rewrite[] = $rewrite;
}
}
?>

Why above code doesn’t generate error ?
The rewrite function is not defined in class Url, and class Url doesn’t extend anybody ??
But then I track deeper, it seems that function rewrite is at seo_url class.

class ControllerCommonSeoUrl extends Controller {
    // Add rewrite to url class
    if ($this->config->get('config_seo_url')) {
        $this->url->addRewrite($this);
    }
    ...
    public function rewrite($link) {
        if ($this->config->get('config_seo_url')) {
            $url_data = parse_url(str_replace('&', '&', $link));
             ....

Why ? I don’t see any connection between ‘Url’ and this ‘ControllerCommonSeoUrl’ yet. Am I missing some concept here ? What I should do to understand these codes ? Need little guidance here.

Answer 1

foreach ($this->rewrite as $rewrite) {

Iterates over whatever values in:

private $rewrite = array();

And maybe that Url->rewrite array contains an instance of ControllerCommonSeoUrl, that would explain why $rewrite->rewrite() calls ControllerCommonSeoUrl->rewrite().

Also, you’d do yourself a favor by trying to learn to use a debugger 🙂