Download MP3 via file_get_contents when URL contains long dash (–) - php

Question

I'm trying to download a set of MP3 files to a ZIP folder. All the MP3's are hosted on S3. My program works perfectly, except when the URL contains a long dash like this: https://s3.amazonaws.com/publicverses/2Corinthians11verse24–33_user400_56.mp3.
Notice the long dash between 24 and 33. This file and others like it show up in the ZIP empty (i.e. 0kb). How can I fix this?
foreach ($files as $file) {
$download_file = file_get_contents($file);
$zip->addFromString(basename($file), $download_file);
}

Answer 1

You need to urlencode() the filename, or any part of the path, if it contains any high order characters like this unicode emdash. For the record, web browsers do this in the background for the sake of user convenience.
It would be easiest to do this before you construct the URL, but if you're stuck with a pre-formed URL with this problem then you need to break it apart and deal only with the pieces that you need to change. Eg:
// from: http://php.net/manual/en/function.parse-url.php#106731
function unparse_url($parsed_url) {
$scheme = isset($parsed_url['scheme']) ? $parsed_url['scheme'] . '://' : '';
$host = isset($parsed_url['host']) ? $parsed_url['host'] : '';
$port = isset($parsed_url['port']) ? ':' . $parsed_url['port'] : '';
$user = isset($parsed_url['user']) ? $parsed_url['user'] : '';
$pass = isset($parsed_url['pass']) ? ':' . $parsed_url['pass'] : '';
$pass = ($user || $pass) ? "$pass#" : '';
$path = isset($parsed_url['path']) ? $parsed_url['path'] : '';
$query = isset($parsed_url['query']) ? '?' . $parsed_url['query'] : '';
$fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : '';
return "$scheme$user$pass$host$port$path$query$fragment";
}
// this function assumes that *nothing* is encoded, otherwise it will
// double-encode the data and likely break it.
function url_encode_parts($url) {
$parts = parse_url($url);
// eg: UTF hostnames are encoded differently
$parts['host'] = idn_to_ascii($parts['host']);
$parts['path'] = implode('/', array_map('urlencode', explode('/', $parts['path'])));
return unparse_url($parts);
}
$url = 'https://s3.amazonaws.com/publicverses/2Corinthians11verse24–33_user400_56.mp3';
var_dump(url_encode_parts($url));
// output:
// string(85) "https://s3.amazonaws.com/publicverses/2Corinthians11verse24%E2%80%9333_user400_56.mp3"
Ref:
http://php.net/manual/en/function.urlencode.php
http://php.net/manual/en/function.parse-url.php
http://php.net/manual/en/function.idn-to-ascii.php

Answer 2

Thanks for the suggestions everyone. In this case, I found that the simplest solution was to update my program such that all long dashes (–) are converted to regular dashes (-) in my URL structure. In other words, I decided to avoid special characters altogether rather than deal with the encoding issues.