无法使用PHP将远程mp3文件下载到服务器

Question

I am trying to download a pronunciation file (approx. 8kb) to server using a server-side PHP. Taking cue from a number of threads discussing this issue, I tried the following:

$numwrd = str_word_count($wrd);
    if($numwrd == 1){
        $html = file_get_html("http://www.dictionaryapi.com/api/v1/references/spanish/xml/" . rawurlencode($wrd) . "?key=" . rawurlencode('6d4d41f9-c28f-4544-9bb3-1b4708d1a4d1'));
        $sn = $html->find('sound');
        if($sn[0] != ""){
            $foldername = findsub($sn[0]->plaintext);
            $filename = explode(".", $sn[0], 2)[0];
            $audiofn = $foldername . $filename . '.mp3';
            $soundurl = 'http://media.merriam-webster.com/audio/prons/es/me/mp3/' . $foldername . '/' . $filename . '.mp3';
            $path = 'amit.mp3';
            $headers = getHeaders($soundurl);
            if ($headers['http_code'] === 200 and $headers['download_content_length'] < 1024*1024) {
              if (download($url, $path)){
                return $audiofn . " " . $soundurl; 
              }
            }
        }
        else { return "not found"; }
    }
    else { return "not found"; }
function getHeaders($url)
{
  $ch = curl_init($url);
  curl_setopt( $ch, CURLOPT_NOBODY, true );
  curl_setopt( $ch, CURLOPT_RETURNTRANSFER, false );
  curl_setopt( $ch, CURLOPT_HEADER, false );
  curl_setopt( $ch, CURLOPT_FOLLOWLOCATION, true );
  curl_setopt( $ch, CURLOPT_MAXREDIRS, 3 );
  curl_exec( $ch );
  $headers = curl_getinfo( $ch );
  curl_close( $ch );

  return $headers;
}
function download($url, $path)
{
  # open file to write
  $fp = fopen ($path, 'w+');
  # start curl
  $ch = curl_init();
  curl_setopt( $ch, CURLOPT_URL, $url );
  # set return transfer to false
  curl_setopt( $ch, CURLOPT_RETURNTRANSFER, false );
  curl_setopt( $ch, CURLOPT_BINARYTRANSFER, true );
  curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, false );
  # increase timeout to download big file
  curl_setopt( $ch, CURLOPT_CONNECTTIMEOUT, 10 );
  # write data to local file
  curl_setopt( $ch, CURLOPT_FILE, $fp );
  # execute curl
  curl_exec( $ch );
  # close curl
  curl_close( $ch );
  # close local file
  fclose( $fp );

  if (filesize($path) > 0) return true;
}

This didn't work so I tried again with file_get_contents. This method however only creates the file but with zero bytes. The values in $foldername, $filename, $audiofn, and $soundurl are evaluating correctly and all these variables have been tested. I can manually download the file by browsing to the URL, right clicking in the browser, and clicking download file as.... What could be wrecking my PHP?

P.S.: I just tried a modified function using cURLand this failed too:

function down($url, $target){//feeding it $soundurl and $path values
    set_time_limit(0);
    $file = fopen(dirname(__FILE__) . $target, 'w+');
    $curl = curl_init($url);
    curl_setopt_array($curl, [
        CURLOPT_URL            => $url,
        CURLOPT_BINARYTRANSFER => 1,
        CURLOPT_RETURNTRANSFER => 1,
        CURLOPT_FILE           => $file,
        CURLOPT_TIMEOUT        => 50,
        CURLOPT_USERAGENT      => 'Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)'
    ]);
    $response = curl_exec($curl);

    if($response === false) {
        throw new \Exception('Curl error: ' . curl_error($curl));
    }
    $response;
}

Answer 1

Finally got it to work! This is what fixed it (line 7):

$filename = explode(".", $sn[0]->plaintext, 2)[0];

The reason I had to add the ->plaintext attribute is because without it, the value being returned to $filename was an xml tag instead of the text inside of that tag. Since the following line of code takes this value as input, this was corrupting the URL being called for download:

$soundurl = 'http://media.merriam-webster.com/audio/prons/es/me/mp3/' . $foldername . '/' . $filename . '.mp3';

Now the file downloads successfully because the URL is being formed correctly.