Add a function to ensure a file exists, optionally checking the mime

type

MD_STD.php

@@ -378,4 +378,35 @@ final class MD_STD {
 
     }
 
+    /**
+     * Checks if a file exists, with one of the expected mime types.
+     *
+     * @param string   $filepath          File path of the file that needs to exist.
+     * @param string[] $accepted_mimetype Mime type the file should have.
+     *
+     * @return void
+     */
+    public static function ensure_file(string $filepath, array $accepted_mimetype = []) {
+
+        if (!\file_exists($filepath)) {
+            throw new MDFileDoesNotExist("File " . basename($filepath) . " does not exist");
+        }
+
+        // Check for mime type follows. If no check is to be done, ignore this.
+        if (empty($accepted_mimetype)) {
+            return;
+        }
+
+        $finfo = \finfo_open(FILEINFO_MIME_TYPE);
+        if (!($mime_type = finfo_file($finfo, $filepath))) {
+            throw new MDWrongFileType("Cannot get mime type of file: " . basename($filepath));
+        }
+        \finfo_close($finfo);
+
+        if (!\in_array($mime_type, $accepted_mimetype)) {
+            throw new MDWrongFileType("Incorrect mime type of file " . \basename($filepath) . ". Mime type is " . \mime_content_type($filepath) . ", accepted any of ['" . \implode("', '", $accepted_mimetype) . "']");
+        }
+
+    }
+
 }