diff --git a/epub.php b/epub.php
index 7957d6b..ec98f0c 100644
--- a/epub.php
+++ b/epub.php
@@ -94,6 +94,23 @@
 		return $innerHTML;
 	}
 
+	function get_json($url)
+	{
+		// cache json in case url expires
+		$tempjsonpath = 'temp/' . hash('md5', $url) . '.json';
+		$json = '';
+		if (file_exists($tempjsonpath))
+		{
+			$json = file_get_contents($tempjsonpath);
+		}
+		else
+		{
+			$json = file_get_contents($url);
+			file_put_contents($tempjsonpath, $json);
+		}
+		return json_decode($json);
+	}
+
 	date_default_timezone_set('Europe/Paris');
 	$date = (new DateTime('today'))->format('Ymd');
 
@@ -110,19 +127,7 @@
 		}
 
 		// cache json in case url expires
-		$tempjsonpath = 'temp/' . hash('md5', $url) . '.json';
-		$json = '';
-		if (file_exists($tempjsonpath))
-		{
-			$json = file_get_contents($tempjsonpath);
-		}
-		else
-		{
-			$json = file_get_contents($url);
-			file_put_contents($tempjsonpath, $json);
-		}
-
-		$publication = json_decode($json);
+		$publication = get_json($url);
 		$pubname = $publication->metadata->title;
 
 		$epub = new TPEpubCreator();
@@ -135,8 +140,7 @@
 		foreach ($list as $entry)
 		{
 			$articleurl = str_replace('material', 'article/' . $entry->hash . '.json', $url);
-			$articlejson = file_get_contents($articleurl);
-			$article = json_decode($articlejson);
+			$article = get_json($articleurl);
 
 			$content = '<h1>' . $article->title . '</h1>';
 			//$content .= '<b>' . $article->abstract . '</b>';