README: add text about page redirects + tweak some words.

... move sections around in a more logical order and tweak some words.

Prompted by a question and feedback from Aleksei, thanks!

1 files changed, 28 insertions, 14 deletions

diff --git a/README b/README
index 4adb7a7..586a25e 100644
--- a/README
+++ b/README
@@ -316,18 +316,6 @@ advertisements, strip tracking parameters and more.
 
 - - -
 
-The fetch function can be overridden in your sfeedrc file. This allows to
-replace the default curl(1) for sfeed_update with any other client to fetch the
-RSS/Atom data:
-
-	# fetch a feed via HTTP/HTTPS etc.
-	# fetch(name, url, feedfile)
-	fetch() {
-		hurl -m 1048576 -t 15 "$2" 2>/dev/null
-	}
-
-- - -
-
 Aggregate feeds. This filters new entries (maximum one day old) and sorts them
 by newest first. Prefix the feed name in the title. Convert the TSV output data
 to an Atom XML feed (again):
@@ -552,6 +540,18 @@ Now you can view feeds in mutt(1) for example.
 
 - - -
 
+The fetch function can be overridden in your sfeedrc file. This allows to
+replace the default curl(1) for sfeed_update with any other client to fetch the
+RSS/Atom data or change the default curl options:
+
+	# fetch a feed via HTTP/HTTPS etc.
+	# fetch(name, url, feedfile)
+	fetch() {
+		hurl -m 1048576 -t 15 "$2" 2>/dev/null
+	}
+
+- - -
+
 Incremental data updates using If-Modified-Since
 
 For servers that support it some incremental updates and bandwidth-saving can
@@ -593,11 +593,11 @@ the --etag-save and --etag-compare options:
 	}
 
 This comes at a cost of some privacy. For example there can be a unique
-generated ETag.
+generated ETag to pin and fingerprint a client.
 
 - - -
 
-CDN's blocking requests due to missing User-Agent
+CDN's blocking requests due to a missing HTTP User-Agent request header
 
 sfeed_update will not send the "User-Agent" header by default for privacy
 reasons.  Some CDNs like Cloudflare don't like this and will block such HTTP
@@ -612,6 +612,20 @@ Firefox 78.
 
 - - -
 
+Page redirects
+
+For security and efficiency reasons by default redirects are not allowed and
+are treated as an error.
+
+For example to prevent hijacking an unencrypted http:// to https:// redirect or
+to not add time of an unnecessary page redirect each time.  It is encouraged to
+use the final redirected url in the sfeedrc config file.
+
+If you want to ignore this advise you can override the fetch() function in the
+sfeedrc file and change the curl options "-L --max-redirs 0".
+
+- - -
+
 Shellscript to export existing newsboat cached items from sqlite3 to the sfeed
 TSV format.