From 2fd22139c6b7b6055ae53c77d56278fce38d1195 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Sat, 14 Sep 2019 13:22:48 -0600
Subject: [PATCH] headers: Ability to mutate request headers including
http.Request.Host
Also a few bug fixes
---
modules/caddyhttp/headers/headers.go | 75 ++++++++++++++++++++--------
1 file changed, 55 insertions(+), 20 deletions(-)
diff --git a/modules/caddyhttp/headers/headers.go b/modules/caddyhttp/headers/headers.go
index 71e575dd2..813b9fec0 100644
--- a/modules/caddyhttp/headers/headers.go
+++ b/modules/caddyhttp/headers/headers.go
@@ -79,15 +79,8 @@ func (h Handler) Validate() error {
func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
repl := r.Context().Value(caddy.ReplacerCtxKey).(caddy.Replacer)
- h.Request.applyTo(r.Header, repl)
-
- // request header's Host is handled specially by the
- // Go standard library, so if that header was changed,
- // change it in the Host field since the Header won't
- // be used
- if intendedHost := r.Header.Get("Host"); intendedHost != "" {
- r.Host = intendedHost
- r.Header.Del("Host")
+ if h.Request != nil {
+ h.Request.ApplyToRequest(r)
}
if h.Response != nil {
@@ -99,7 +92,7 @@ func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhtt
headerOps: h.Response.HeaderOps,
}
} else {
- h.Response.applyTo(w.Header(), repl)
+ h.Response.ApplyTo(w.Header(), repl)
}
}
@@ -160,11 +153,9 @@ type RespHeaderOps struct {
Deferred bool `json:"deferred,omitempty"`
}
-func (ops *HeaderOps) applyTo(hdr http.Header, repl caddy.Replacer) {
- if ops == nil {
- return
- }
-
+// ApplyTo applies ops to hdr using repl.
+func (ops HeaderOps) ApplyTo(hdr http.Header, repl caddy.Replacer) {
+ // add
for fieldName, vals := range ops.Add {
fieldName = repl.ReplaceAll(fieldName, "")
for _, v := range vals {
@@ -172,22 +163,28 @@ func (ops *HeaderOps) applyTo(hdr http.Header, repl caddy.Replacer) {
}
}
+ // set
for fieldName, vals := range ops.Set {
fieldName = repl.ReplaceAll(fieldName, "")
+ var newVals []string
for i := range vals {
- vals[i] = repl.ReplaceAll(vals[i], "")
+ // append to new slice so we don't overwrite
+ // the original values in ops.Set
+ newVals = append(newVals, repl.ReplaceAll(vals[i], ""))
}
- hdr.Set(fieldName, strings.Join(vals, ","))
+ hdr.Set(fieldName, strings.Join(newVals, ","))
}
+ // delete
for _, fieldName := range ops.Delete {
hdr.Del(repl.ReplaceAll(fieldName, ""))
}
+ // replace
for fieldName, replacements := range ops.Replace {
fieldName = repl.ReplaceAll(fieldName, "")
- // perform replacements across all fields
+ // all fields...
if fieldName == "*" {
for _, r := range replacements {
search := repl.ReplaceAll(r.Search, "")
@@ -205,7 +202,7 @@ func (ops *HeaderOps) applyTo(hdr http.Header, repl caddy.Replacer) {
continue
}
- // perform replacements only with the named field
+ // ...or only with the named field
for _, r := range replacements {
search := repl.ReplaceAll(r.Search, "")
replace := repl.ReplaceAll(r.Replace, "")
@@ -220,6 +217,42 @@ func (ops *HeaderOps) applyTo(hdr http.Header, repl caddy.Replacer) {
}
}
+// ApplyToRequest applies ops to r, specially handling the Host
+// header which the standard library does not include with the
+// header map with all the others. This method mutates r.Host.
+func (ops HeaderOps) ApplyToRequest(r *http.Request) {
+ repl := r.Context().Value(caddy.ReplacerCtxKey).(caddy.Replacer)
+
+ // capture the current Host header so we can
+ // reset to it when we're done
+ origHost, hadHost := r.Header["Host"]
+
+ // append r.Host; this way, we know that our value
+ // was last in the list, and if an Add operation
+ // appended something else after it, that's probably
+ // fine because it's weird to have multiple Host
+ // headers anyway and presumably the one they added
+ // is the one they wanted
+ r.Header["Host"] = append(r.Header["Host"], r.Host)
+
+ // apply header operations
+ ops.ApplyTo(r.Header, repl)
+
+ // retrieve the last Host value (likely the one we appended)
+ if len(r.Header["Host"]) > 0 {
+ r.Host = r.Header["Host"][len(r.Header["Host"])-1]
+ } else {
+ r.Host = ""
+ }
+
+ // reset the Host header slice
+ if hadHost {
+ r.Header["Host"] = origHost
+ } else {
+ delete(r.Header, "Host")
+ }
+}
+
// responseWriterWrapper defers response header
// operations until WriteHeader is called.
type responseWriterWrapper struct {
@@ -236,7 +269,9 @@ func (rww *responseWriterWrapper) WriteHeader(status int) {
}
rww.wroteHeader = true
if rww.require == nil || rww.require.Match(status, rww.ResponseWriterWrapper.Header()) {
- rww.headerOps.applyTo(rww.ResponseWriterWrapper.Header(), rww.replacer)
+ if rww.headerOps != nil {
+ rww.headerOps.ApplyTo(rww.ResponseWriterWrapper.Header(), rww.replacer)
+ }
}
rww.ResponseWriterWrapper.WriteHeader(status)
}