Php method, from the Internet to download a website program, this step did not understand what is to do, ask for advice

Php method, from the Internet to download a website program, this method did not understand what is doing, ask for advice
function seo ($ident)
{
Include App_path. " /plus/seo.cache.php ";
$seo = $seo [$ident];
if (Is_array ($seo)) {
foreach ($seo as $k = = $v) {
if ($v [affiliation]!= "") {
[Email protected] (",", $v [' affiliation ']);
if ($_session[did]!= "" && In_array ($_session[' did '), $did)) {
$seo = $v;
}elseif (In_array ("0", $did)) {
$seo = $v;
}
}else{
$seo = $v;
}
}
}
$data = $this->data;
if (Is_array ($seo))
{
$cityname = $_session[' cityname ']?$_session[' CityName '): $this->config["sy_indexcity"];
foreach ($seo as $key = $value)
{
$seo [$key] = Str_replace ("{webname}", $this->config[' Sy_webname '], $seo [$key]);
$seo [$key] = Str_replace ("{Webkeyword}", $this->config[' Sy_webkeyword '], $seo [$key]);
$seo [$key] = Str_replace ("{Webdesc}", $this->config[' Sy_webmeta '], $seo [$key]);
$seo [$key] = Str_replace ("{Weburl}", $this->config[' Sy_weburl '], $seo [$key]);
$seo [$key] = Str_replace ("{City}", $cityname, $seo [$key]);
if (Is_array ($data)) {
foreach ($data as $k = = $v) {
$seo [$key] = Str_replace ("{". $k. "}", $v, $seo [$key]);
}
}
if ([email protected] (' {seacrh_class} ', $seo [$key])) {
$rdata = $this->get_search_class ($ident, $key);
$seo [$key] = Str_replace ("{seacrh_class}", $rdata, $seo [$key]);
}
$seo [$key]=str_replace (",", $seo [$key]);
$seo [$key]=str_replace (Array ("--", "--"), '-', $seo [$key]);
$seo [$key]=str_replace (Array ("--", "--"), '-', $seo [$key]);
}
}
$this->yunset ("title", $seo [' title ']);
$this->yunset ("keywords", $seo [' keywords ']);
$this->yunset ("description", $seo [' description ']);
}
function Yunset ($name, $value) {
$this->tpl->assign ($name, $value);
}
------Solution--------------------
Optimize Address bar Links
------Solution--------------------
You can explain to me which sentence you don't understand.

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