/**
* Fetches content of file from Internet (using proxy if defined). Uses cURL extension if present.
* Due to security concerns only downloads from http(s) sources are supported.
*
* @category files
* @param string $url file url starting with http(s)://
* @param array $headers http headers, null if none. If set, should be an
* associative array of header name => value pairs.
* @param array $postdata array means use POST request with given parameters
* @param bool $fullresponse return headers, responses, etc in a similar way snoopy does
* (if false, just returns content)
* @param int $timeout timeout for complete download process including all file transfer
* (default 5 minutes)
* @param int $connecttimeout timeout for connection to server; this is the timeout that
* usually happens if the remote server is completely down (default 20 seconds);
* may not work when using proxy
* @param bool $skipcertverify If true, the peer's SSL certificate will not be checked.
* Only use this when already in a trusted location.
* @param string $tofile store the downloaded content to file instead of returning it.
* @param bool $calctimeout false by default, true enables an extra head request to try and determine
* filesize and appropriately larger timeout based on $CFG->curltimeoutkbitrate
* @return stdClass|string|bool stdClass object if $fullresponse is true, false if request failed, true
* if file downloaded into $tofile successfully or the file content as a string.
*/
function download_file_content($url, $headers = null, $postdata = null, $fullresponse = false, $timeout = 300, $connecttimeout = 20, $skipcertverify = false, $tofile = NULL, $calctimeout = false)
{
global $CFG;
// Only http and https links supported.
if (!preg_match('|^https?://|i', $url)) {
if ($fullresponse) {
$response = new stdClass();
$response->status = 0;
$response->headers = array();
$response->response_code = 'Invalid protocol specified in url';
$response->results = '';
$response->error = 'Invalid protocol specified in url';
return $response;
} else {
return false;
}
}
$options = array();
$headers2 = array();
if (is_array($headers)) {
foreach ($headers as $key => $value) {
if (is_numeric($key)) {
$headers2[] = $value;
} else {
$headers2[] = "{$key}: {$value}";
}
}
}
if ($skipcertverify) {
$options['CURLOPT_SSL_VERIFYPEER'] = false;
} else {
$options['CURLOPT_SSL_VERIFYPEER'] = true;
}
$options['CURLOPT_CONNECTTIMEOUT'] = $connecttimeout;
$options['CURLOPT_FOLLOWLOCATION'] = 1;
$options['CURLOPT_MAXREDIRS'] = 5;
// Use POST if requested.
if (is_array($postdata)) {
$postdata = format_postdata_for_curlcall($postdata);
} else {
if (empty($postdata)) {
$postdata = null;
}
}
// Optionally attempt to get more correct timeout by fetching the file size.
if (!isset($CFG->curltimeoutkbitrate)) {
// Use very slow rate of 56kbps as a timeout speed when not set.
$bitrate = 56;
} else {
$bitrate = $CFG->curltimeoutkbitrate;
}
if ($calctimeout and !isset($postdata)) {
$curl = new curl();
$curl->setHeader($headers2);
$curl->head($url, $postdata, $options);
$info = $curl->get_info();
$error_no = $curl->get_errno();
if (!$error_no && $info['download_content_length'] > 0) {
// No curl errors - adjust for large files only - take max timeout.
$timeout = max($timeout, ceil($info['download_content_length'] * 8 / ($bitrate * 1024)));
}
}
$curl = new curl();
$curl->setHeader($headers2);
$options['CURLOPT_RETURNTRANSFER'] = true;
$options['CURLOPT_NOBODY'] = false;
$options['CURLOPT_TIMEOUT'] = $timeout;
if ($tofile) {
$fh = fopen($tofile, 'w');
if (!$fh) {
if ($fullresponse) {
$response = new stdClass();
$response->status = 0;
$response->headers = array();
$response->response_code = 'Can not write to file';
$response->results = false;
$response->error = 'Can not write to file';
return $response;
} else {
return false;
}
}
$options['CURLOPT_FILE'] = $fh;
}
if (isset($postdata)) {
$content = $curl->post($url, $postdata, $options);
} else {
$content = $curl->get($url, null, $options);
}
if ($tofile) {
fclose($fh);
@chmod($tofile, $CFG->filepermissions);
}
/*
// Try to detect encoding problems.
if ((curl_errno($ch) == 23 or curl_errno($ch) == 61) and defined('CURLOPT_ENCODING')) {
curl_setopt($ch, CURLOPT_ENCODING, 'none');
$result = curl_exec($ch);
}
*/
$info = $curl->get_info();
$error_no = $curl->get_errno();
$rawheaders = $curl->get_raw_response();
if ($error_no) {
$error = $content;
if (!$fullresponse) {
debugging("cURL request for \"{$url}\" failed with: {$error} ({$error_no})", DEBUG_ALL);
return false;
}
$response = new stdClass();
if ($error_no == 28) {
$response->status = '-100';
// Mimic snoopy.
} else {
$response->status = '0';
}
$response->headers = array();
$response->response_code = $error;
$response->results = false;
$response->error = $error;
return $response;
}
if ($tofile) {
$content = true;
}
if (empty($info['http_code'])) {
// For security reasons we support only true http connections (Location: file:// exploit prevention).
$response = new stdClass();
$response->status = '0';
$response->headers = array();
$response->response_code = 'Unknown cURL error';
$response->results = false;
// do NOT change this, we really want to ignore the result!
$response->error = 'Unknown cURL error';
} else {
$response = new stdClass();
$response->status = (string) $info['http_code'];
$response->headers = $rawheaders;
$response->results = $content;
$response->error = '';
// There might be multiple headers on redirect, find the status of the last one.
$firstline = true;
foreach ($rawheaders as $line) {
if ($firstline) {
$response->response_code = $line;
$firstline = false;
}
if (trim($line, "\r\n") === '') {
$firstline = true;
}
}
}
if ($fullresponse) {
return $response;
}
if ($info['http_code'] != 200) {
debugging("cURL request for \"{$url}\" failed, HTTP response code: " . $response->response_code, DEBUG_ALL);
return false;
}
return $response->results;
}
