How to use api in php

$params = array('key' => '8d284859d04cfeeea6b0771f754adb49',
   'location' => $_COOKIE["lng"].",".$_COOKIE["lat"]);

$url3 = "http://restapi.amap.com/v3/geocode/regeo";

if (strripos('?', $url3)) {
 $url4 = $url3 . http_build_query($params);
} else {
 $url4 = $url3 . '?' . http_build_query($params);
}

$ret2 = json_decode(file_get_contents($url4));

var_dump($ret);

$url2 = 'http://www.sojson.com/open/api/weather/json.shtml';    
$params = array('city' => '长沙');   
if (strripos('?', $url2)) {
    $url = $url2 . http_build_query($params);
     }
else {
    $url = $url2 . '?' . http_build_query($params);
     }
     $data = 'city=长沙';
     $curlobj = curl_init();   
     curl_setopt($curlobj, CURLOPT_URL, $url); 
     curl_setopt($curlobj, CURLOPT_HEADER, 0);
     curl_exec($curlobj);