fix: handle auth fail freshrss, add doc (#121)

README.md

@@ -81,6 +81,11 @@ backends:
     password: muchstrong
 ```
 
+#### FreshRSS
+To use freshrss you need to enable API access and set the API password explicitly, separate to your user password.
+1. To enable the API go to Settings > Authentication > Allow API access.  
+1. You can set the API password in Settings > Profile > API password.  
+
 ### Openers
 By default links are opened in the browser, you can specify commands to open certain links based on a regex string.   
 `regex` can be any valid golang regex string, it will be matched against the feed item link.  

internal/config/backends.go

@@ -42,6 +42,10 @@ func getFreshRSSFeeds(config *FreshRSSBackend) ([]Feed, error) {
 		return []Feed{}, err
 	}
 
+	if resp.StatusCode < 200 || resp.StatusCode > 299 {
+		return []Feed{}, fmt.Errorf("could not login to freshrss, statusCode: %d", resp.StatusCode)
+	}
+
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return []Feed{}, err