JSON response is null with error 4

Question

I'm trying to extract the prices of some cryptocurrencies from this JSON:

https://min-api.cryptocompare.com/data/pricemulti?fsyms=BTC,ETH&tsyms=XRP,BCH,LTC,NEO,ADA,XLM,EOS,XMR,DASH

It works perfectly fine when you access it directly or thru Postman but a response of error #4 appears when I'm trying to cURL it.

Code:

 header('Content-Type: text/html; charset=utf-8', true);
function getCurrencies()
{
 try {
 $curlDefault = array(
 CURLOPT_PORT => 80, 
 CURLOPT_SSL_VERIFYPEER => TRUE,
 CURLOPT_RETURNTRANSFER => TRUE,
 CURLOPT_FOLLOWLOCATION => TRUE,
 CURLOPT_ENCODING => '',
 CURLOPT_HTTPHEADER => array(
 'Proxy-Connection: Close',
 'User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1017.2 Safari/535.19',
 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
 'Accept-Encoding: gzip,deflate,sdch',
 'Accept-Language: en-US,en;q=0.8',
 'Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3',
 'Cookie: __qca=blabla',
 'Connection: Close',
 ),
 CURLOPT_VERBOSE => TRUE
 );
 $url = "https://min-api.cryptocompare.com/data/pricemulti?fsyms=BTC,ETH&tsyms=XRP,BCH,LTC,NEO,ADA,XLM,EOS,XMR,DASH";
 $handle = curl_init($url);
 curl_setopt_array($handle, $curlDefault);
 $res = curl_exec($handle);
 curl_close($handle);
 return $res;
 } catch (Exception $e) {
 trigger_error(sprintf(
 'Curl failed with error #%d: %s',
 $e->getCode(), $e->getMessage()),
 E_USER_ERROR);
 }
}
$currencty_res = json_decode(getCurrencies(), true);
if (is_null($currencty_res)) {
 die("Json decoding failed with error: ". json_last_error());
}
var_dump($currencty_res);

The second question would be how to format the response to something like:

foreach ($currencty_res[0] as $key => $item) {
if (!empty($item)) {
 $currencyA = $item;
 $currencyB = $item[0];
 $value = $item[0][0];
 echo $currencyA . '/' . $currencyB . ' : ' . $value;
 }
}

So it will result in echo BTC/XRP : 11515.43 for each of the currency pairs.

BTC/XRP : 11515.43
BTC/BCH : 8.87
BTC/LTC : 49.83
...
ETH/XRP : 898.2
ETH/BCH : 0.6921
ETH/LTC : 3.89

• Sharad Khanna: Just out of curiosity are you using the Bittrex API? Because if so I can post code on how to get the JSON and parse it.
• Gabriel Santos: To see what's the error: http://php.net/manual/en/function.json-last-error-msg.php
• Ricardo: @SharadKhanna - I'm trying min-api.cryptocompare.com but if Bittrex has no limits (I need it to retrieve data every 5 sec) then yea, why not - I would appreciate this info.
• Sharad Khanna: Okay, will do, I hope it will help

Answer 1

I have made little changes and now work (see comments)

function getCurrencies() {
 $url = "https://min-api.cryptocompare.com/data/pricemulti?fsyms=BTC,ETH&tsyms=XRP,BCH,LTC,NEO,ADA,XLM,EOS,XMR,DASH";
 $options = array( 
 CURLOPT_RETURNTRANSFER => true, // return web page
 CURLOPT_HEADER => false, // don't return headers 
 CURLOPT_FOLLOWLOCATION => true, // follow redirects
 CURLOPT_MAXREDIRS => 10, // stop after 10 redirects
 CURLOPT_ENCODING => "", // handle compressed
 CURLOPT_USERAGENT => $_SERVER['HTTP_USER_AGENT'], // name of client
 CURLOPT_AUTOREFERER => false, // set referrer on redirect
 CURLOPT_CONNECTTIMEOUT => 120, // time-out on connect 
 CURLOPT_TIMEOUT => 1, // time-out on response
 CURLOPT_SSL_VERIFYPEER => false, //avoid ssl autentication
 ); 
 $ch = curl_init($url);
 curl_setopt_array($ch, $options);
 $content = curl_exec($ch);
 curl_close($ch);
 return $content;
}
$currencty_res = json_decode(getCurrencies(), true);
try_again:
if(!$currencty_res){
 sleep(2);
 //I saw some time fail so try_again;
 goto try_again;
}
print_r($currencty_res);

The result is:

Array
(
 [BTC] => Array
 (
 [XRP] => 11481.06
 [BCH] => 8.86
 [LTC] => 49.68
 [NEO] => 103.34
 [ADA] => 43859.65
 [XLM] => 30892.8
 [EOS] => 1529.29
 [XMR] => 33.46
 [DASH] => 18.46
 )
 [ETH] => Array
 (
 [XRP] => 895.06
 [BCH] => 0.6905
 [LTC] => 3.87
 [NEO] => 8.06
 [ADA] => 3419.3
 [XLM] => 2408.4
 [EOS] => 119.32
 [XMR] => 2.61
 [DASH] => 1.44
 )
)

For the second question try this:

foreach ($currencty_res as $currencyA => $array_currencyB) {
 foreach($array_currencyB as $currencyB => $value){
 echo $currencyA . '/' . $currencyB . ' : ' . $value."<br>";
 }
}

That return:

BTC/XRP : 11436.41
BTC/BCH : 8.83
BTC/LTC : 49.65
BTC/NEO : 103.1
BTC/ADA : 43802.01
BTC/XLM : 30864.2
BTC/EOS : 1525.09
BTC/XMR : 33.5
BTC/DASH : 18.47
ETH/XRP : 893.3
ETH/BCH : 0.69
ETH/LTC : 3.88
ETH/NEO : 8.05
ETH/ADA : 3421.38
ETH/XLM : 2410.8
ETH/EOS : 119.23
ETH/XMR : 2.62
ETH/DASH : 1.44

• Ricardo: This works! Could you please address the second question as well? I'm having a hard time with arrays and json...
• Ricardo: I would never think of this, thank you for your help :)