From 0fb87eba3f763658e3bf864a9cf78adbdae590c6 Mon Sep 17 00:00:00 2001
From: Frédéric Guillot <fred@miniflux.net>
Date: Wed, 7 Feb 2018 18:47:47 -0800
Subject: Improve error handling when the response is empty

---
 reader/feed/parser.go         |  5 ++++-
 reader/feed/parser_test.go    |  7 +++++++
 reader/subscription/finder.go | 12 +++++++++++-
 3 files changed, 22 insertions(+), 2 deletions(-)

(limited to 'reader')

diff --git a/reader/feed/parser.go b/reader/feed/parser.go
index a2b39ed..c04836a 100644
--- a/reader/feed/parser.go
+++ b/reader/feed/parser.go
@@ -69,7 +69,10 @@ func parseFeed(r io.Reader) (*model.Feed, error) {
 	defer timer.ExecutionTime(time.Now(), "[Feed:ParseFeed]")
 
 	var buffer bytes.Buffer
-	io.Copy(&buffer, r)
+	size, _ := io.Copy(&buffer, r)
+	if size == 0 {
+		return nil, errors.New("This feed is empty")
+	}
 
 	reader := bytes.NewReader(buffer.Bytes())
 	format := DetectFeedFormat(reader)
diff --git a/reader/feed/parser_test.go b/reader/feed/parser_test.go
index b201caf..31dbedf 100644
--- a/reader/feed/parser_test.go
+++ b/reader/feed/parser_test.go
@@ -205,3 +205,10 @@ func TestParseUnknownFeed(t *testing.T) {
 		t.Error("ParseFeed must returns an error")
 	}
 }
+
+func TestParseEmptyFeed(t *testing.T) {
+	_, err := parseFeed(bytes.NewBufferString(""))
+	if err == nil {
+		t.Error("ParseFeed must returns an error")
+	}
+}
diff --git a/reader/subscription/finder.go b/reader/subscription/finder.go
index 835991c..8e361b7 100644
--- a/reader/subscription/finder.go
+++ b/reader/subscription/finder.go
@@ -23,6 +23,7 @@ import (
 var (
 	errConnectionFailure = "Unable to open this link: %v"
 	errUnreadableDoc     = "Unable to analyze this page: %v"
+	errEmptyBody         = "This web page is empty"
 )
 
 // FindSubscriptions downloads and try to find one or more subscriptions from an URL.
@@ -35,13 +36,22 @@ func FindSubscriptions(websiteURL string) (Subscriptions, error) {
 		return nil, errors.NewLocalizedError(errConnectionFailure, err)
 	}
 
+	// Content-Length = -1 when no Content-Length header is sent
+	if response.ContentLength == 0 {
+		return nil, errors.NewLocalizedError(errEmptyBody)
+	}
+
 	body, err := response.NormalizeBodyEncoding()
 	if err != nil {
 		return nil, err
 	}
 
 	var buffer bytes.Buffer
-	io.Copy(&buffer, body)
+	size, _ := io.Copy(&buffer, body)
+	if size == 0 {
+		return nil, errors.NewLocalizedError(errEmptyBody)
+	}
+
 	reader := bytes.NewReader(buffer.Bytes())
 
 	if format := feed.DetectFeedFormat(reader); format != feed.FormatUnknown {
-- 
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