DOC: clarify the fact that replace-uri works on a full URI
With H2 deployments becoming more common, replace-uri starts to hit
users by not always matching absolute URIs due to rules expecting the
URI to start with a '/'.
(cherry picked from commit 62b5913380d6820bb249672bbf57b9377ceaf9e1)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 28a5eba5ab164ddd073a57b4928589850f7cf9b1)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/doc/configuration.txt b/doc/configuration.txt
index e63584c..99046f4 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -4541,17 +4541,23 @@
than certain ACLs, so rare replacements may benefit from a condition to avoid
performing the evaluation at all if it does not match.
- Example:
- # prefix /foo : turn /bar?q=1 into /foo/bar?q=1 :
- http-request replace-uri (.*) /foo\1
+ IMPORTANT NOTE: historically in HTTP/1.x, the vast majority of requests sent
+ by browsers use the "origin form", which differs from the "absolute form" in
+ that they do not contain a scheme nor authority in the URI portion. Mostly
+ only requests sent to proxies, those forged by hand and some emitted by
+ certain applications use the absolute form. As such, "replace-uri" usually
+ works fine most of the time in HTTP/1.x with rules starting with a "/". But
+ with HTTP/2, clients are encouraged to send absolute URIs only, which look
+ like the ones HTTP/1 clients use to talk to proxies. Such partial replace-uri
+ rules may then fail in HTTP/2 when they work in HTTP/1. Either the rules need
+ to be adapted to optionally match a scheme and authority.
- # suffix /foo : turn /bar?q=1 into /bar/foo?q=1 :
- http-request replace-uri ([^?]*)(\?(.*))? \1/foo\2
+ Example:
+ # rewrite all "http" absolute requests to "https":
+ http-request replace-uri ^http://(.*) https://\1
- # strip /foo : turn /foo/bar?q=1 into /bar?q=1
- http-request replace-uri /foo/(.*) /\1
- # or more efficient if only some requests match :
- http-request replace-uri /foo/(.*) /\1 if { url_beg /foo/ }
+ # prefix /foo : turn /bar?q=1 into /foo/bar?q=1 :
+ http-request replace-uri ([^/:]*://[^/]*)?(.*) \1/foo\2
http-request replace-value <name> <match-regex> <replace-fmt>
[ { if | unless } <condition> ]