A path holding a character Go escapes reaches the app as the client sent it (closes #126)

ReverseProxy sends the path URL.EscapedPath gives, which decodes and
escapes again a path holding a character such as |, turning %2F into /.
The path as sent now goes in URL.Opaque, which Go sends as it is; the
rate limit and WAF exempt paths and the log line's path use the same
path. A path starting with // is left as before: Go would send it in
Opaque as a scheme and host.

Model: opus-5-5

internal/proxy/ratelimits_test.go

@@ -185,6 +185,9 @@ func TestRateLimitCountsPathsThatAreNotExempt(t *testing.T) {
 		"/assets/x%2Fy",
 		"/assets/x%2fy",
 		`/assets/x\y`,
+		// The same with a character Go escapes, |, for which Go's
+		// URL.EscapedPath gives /assets/x/y%7Cz, with no encoded slash.
+		"/assets/x%2Fy|z",
 	} {
 		t.Run(sent, func(t *testing.T) {
 			t.Parallel()