Move file operations to separate File object

Use curl for remote file operations
Do file operations in memory instead of file system
Add config.php to .gitignore

.gitignore

@@ -1,2 +1,3 @@
 vendor/
 composer.lock
+config.php

File.class.php

@@ -0,0 +1,82 @@
+<?php
+
+class File {
+    public $url;
+
+    function __construct($url) {
+        $this->url = $url;
+    }
+
+    function get_headers($follow=true) {
+        $ch = curl_init();
+        curl_setopt($ch, CURLOPT_URL, $this->url);
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, $follow);
+        curl_setopt($ch, CURLOPT_HEADER, true);
+        curl_setopt($ch, CURLOPT_NOBODY, true);
+        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
+        
+        $output = curl_exec($ch);
+
+        curl_close($ch);
+
+        $headers = [];
+        $output = rtrim($output);
+        $data = explode("\n", $output);
+        $headers['status'] = $data[0];
+        array_shift($data);
+
+        foreach($data as $part) {
+            $middle = explode(":",$part,2);
+            if ( !isset($middle[1]) ) { $middle[1] = null; }
+            $headers[trim($middle[0])] = trim($middle[1]);
+        }
+
+        return $headers;
+    }
+
+    function get_status($follow=true) {
+        return $this->get_headers($follow)["status"];
+    }
+
+    function get_filename($follow=true) {
+        $content = $this->get_headers($follow);
+        $content = array_change_key_case($content, CASE_LOWER);
+    
+        if ($content['content-disposition']) {
+            $tmp_name = explode('=', $content['content-disposition']);
+            if ($tmp_name[1]) $realfilename = trim($tmp_name[1],'";\'');
+        };
+        
+        if (!$realfilename)  {
+            $stripped_url = preg_replace('/\\?.*/', '', $this->url);
+            $stripped_url = preg_replace('/\\/$/', '', $stripped_url);
+            $realfilename = basename($stripped_url);
+        }
+    
+        return $realfilename;
+    }
+
+    function fetch_file($write=false, $path=null, $follow=true) {
+        $ch = curl_init();
+        curl_setopt($ch, CURLOPT_URL, $this->url);
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, $follow);
+        curl_setopt($ch, CURLOPT_HEADER, false);
+        curl_setopt($ch, CURLOPT_NOBODY, false);
+        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
+
+        $output = curl_exec($ch);
+        
+        if(curl_errno($ch)) throw new Exception('Error downloading file. ' . curl_error($ch));
+
+        curl_close($ch);
+        
+        if ($write) {
+            if (!$path) $path = tempnam(sys_get_temp_dir(), "EXPMAIL_");
+            if (!file_put_contents($path, $output)) throw new Exception('Error saving file to ' . $path);
+        }
+
+        return ($write ? $path : $output);
+    }
+}

sender.php

@@ -3,6 +3,7 @@
 require_once 'vendor/autoload.php';
 require_once 'config.php';
 require_once 'helpers.php';
+require_once 'File.class.php';
 
 use PHPMailer\PHPMailer\PHPMailer;
 use PHPMailer\PHPMailer\Exception;
@@ -56,10 +57,11 @@ try {
     $mailer->AltBody = ($html ? $text : null);
 
     foreach ($json["attachments"] as $attachment) {
-        $tempfile = tempnam(sys_get_temp_dir(), "EXPMAIL_");
-        file_put_contents($tempfile, file_get_contents($attachment["url"]));
-        $filename = ($attachment["filename"] ? $attachment["filename"] : getFilename($attachment["url"]));
-        $mailer->addAttachment($tempfile, $filename);
+        $file = new File($attachment["url"]);
+        if ($file->get_status() >= 400) throw new Exception("Error downloading " . $attachment["url"] . " - Status: " . $file->get_status());
+        $content = $file->fetch_file();
+        $filename = ($attachment["filename"] ? $attachment["filename"] : $file->get_filename());
+        $mailer->addStringAttachment($content, $filename);
     }
 
     $mailer->send();
@@ -68,7 +70,7 @@ try {
         "status" => "success"
     );
 
-} catch (Exception $e) {
+} catch (\Exception $e) {
     $response = array(
         "status" => "error",
         "error" => "{$e->getMessage()}"