From ae6954f0e4491c2d2223a78dab262349d72ef72f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Bar=C3=A1=C5=A1ek?= <janbarasek@gmail.com>
Date: Sat, 16 Oct 2021 17:58:59 +0200
Subject: [PATCH] Feed: Add edge conditions.

---
 src/Feed.php | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/Feed.php b/src/Feed.php
index 3bb7fef..1a61eed 100644
--- a/src/Feed.php
+++ b/src/Feed.php
@@ -113,13 +113,20 @@ private function downloadRawFeed(string $url): string
 		if ($haystack === false) {
 			trigger_error('Feed URL "' . $url . '" is broken.');
 		}
+		$haystack = trim((string) $haystack);
+		if ($haystack === '') {
+			throw new \RuntimeException('Feed response for URL "' . $url . '" is empty.');
+		}
 
-		return (string) $haystack;
+		return $haystack;
 	}
 
 
 	private function writeCache(string $url, string $content, ?string $expiration = null): void
 	{
+		if ($content === '') { // ignore empty content
+			return;
+		}
 		$this->cache->save($url, $content, [
 			Cache::EXPIRATION => $expiration ?? $this->expirationTime,
 		]);