来自JSON的CURL的getRemoteContents返回0

Question

Trying to get the value from 'price_usd' using get remote contents in PHP from the following JSON: https://api.coinmarketcap.com/v1/ticker/bitcoin/

It returns a 0 value. Can someone please explain what I am doing wrong here? Thanks! See code:

public function getUSD(){

        $json = json_decode($this->getRemoteContents("https://api.coinmarketcap.com/v1/ticker/bitcoin/"), true);

        return isset ($json['price_usd'])?($json['price_usd']):0;

    }

    public function getRemoteContents($url, $retries=5) {

        $USER_AGENT = $_SERVER['HTTP_USER_AGENT'];

        $result = "";

        if (extension_loaded('curl') === true) {

            $ch=curl_init();

            curl_setopt($ch, CURLOPT_TIMEOUT, $this->timeout);

            curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $this->timeout);

            curl_setopt($ch, CURLOPT_USERAGENT, $USER_AGENT);

            curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);

            curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);

            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);

            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);

            curl_setopt($ch, CURLOPT_URL, $url);

            $result = curl_exec($ch);

            curl_close($ch);

            unset($ch);

        } else {

            $options  = array('http' => array('user_agent' => $USER_AGENT, 'timeout' => $this->timeout));

            $context  = stream_context_create($options);

            $result = trim(file_get_contents($url,false, $context));

        }

        if (trim($result)=="") {

            $retries-=1;

            if ($retries >= 1) {

                return $this->getRemoteContents($url,$retries);

            }

        }

    return $result;

    } 

I think it has something to do with the return isset line?

Answer 1

You need to check for $json[0]['price_usd'].