From 0fb87eba3f763658e3bf864a9cf78adbdae590c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Guillot?= <fred@miniflux.net>
Date: Wed, 7 Feb 2018 18:47:47 -0800
Subject: [PATCH] Improve error handling when the response is empty

---
 locale/translations.go         |  7 ++++---
 locale/translations/fr_FR.json |  3 ++-
 reader/feed/parser.go          |  5 ++++-
 reader/feed/parser_test.go     |  7 +++++++
 reader/subscription/finder.go  | 12 +++++++++++-
 5 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/locale/translations.go b/locale/translations.go
index 0291ebdd..d626b895 100644
--- a/locale/translations.go
+++ b/locale/translations.go
@@ -1,5 +1,5 @@
 // Code generated by go generate; DO NOT EDIT.
-// 2018-02-07 12:24:51.492778 +0100 CET m=+0.025245211
+// 2018-02-07 18:40:34.783083402 -0800 PST m=+0.035977512
 
 package locale
 
@@ -439,7 +439,8 @@ var translations = map[string]string{
     "Fever API endpoint:": "Point de terminaison de l'API Fever :",
     "Miniflux API": "API de Miniflux",
     "API Endpoint": "Point de terminaison de l'API",
-    "Your account password": "Le mot de passe de votre compte"
+    "Your account password": "Le mot de passe de votre compte",
+    "This web page is empty": "Cette page web est vide"
 }
 `,
 }
@@ -447,5 +448,5 @@ var translations = map[string]string{
 var translationsChecksums = map[string]string{
 	"de_DE": "f4a66bffedb7bf99294281da5a1fa78901509db67a9fba15a160b656feb1425a",
 	"en_US": "6fe95384260941e8a5a3c695a655a932e0a8a6a572c1e45cb2b1ae8baa01b897",
-	"fr_FR": "eb05f9d8cf36bf943388f4027fede1c565576ccdd38b71c5ed1bb18cb60744f4",
+	"fr_FR": "3b8f4d329ca851f461c973bbdb77459006ba7b4d9bd49139d4002af67b4c3d4e",
 }
diff --git a/locale/translations/fr_FR.json b/locale/translations/fr_FR.json
index 2dae3447..9e64dde1 100644
--- a/locale/translations/fr_FR.json
+++ b/locale/translations/fr_FR.json
@@ -209,5 +209,6 @@
     "Fever API endpoint:": "Point de terminaison de l'API Fever :",
     "Miniflux API": "API de Miniflux",
     "API Endpoint": "Point de terminaison de l'API",
-    "Your account password": "Le mot de passe de votre compte"
+    "Your account password": "Le mot de passe de votre compte",
+    "This web page is empty": "Cette page web est vide"
 }
diff --git a/reader/feed/parser.go b/reader/feed/parser.go
index a2b39edc..c04836a6 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 b201cafc..31dbedf2 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 835991ca..8e361b7e 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 {