mirror of
https://github.com/caddyserver/caddy.git
synced 2024-11-29 12:16:16 +08:00
headers: Add ability to replace substrings in header fields
This will probably be useful so the proxy can rewrite header values.
This commit is contained in:
parent
46aaf02371
commit
c09e86fddc
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@ -15,7 +15,9 @@
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package headers
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import (
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"fmt"
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"net/http"
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"regexp"
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"strings"
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"github.com/caddyserver/caddy/v2"
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@ -23,43 +25,61 @@ import (
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)
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func init() {
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caddy.RegisterModule(Headers{})
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caddy.RegisterModule(Handler{})
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}
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// Headers is a middleware which can mutate HTTP headers.
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type Headers struct {
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// Handler is a middleware which can mutate HTTP headers.
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type Handler struct {
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Request *HeaderOps `json:"request,omitempty"`
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Response *RespHeaderOps `json:"response,omitempty"`
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}
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// CaddyModule returns the Caddy module information.
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func (Headers) CaddyModule() caddy.ModuleInfo {
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func (Handler) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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Name: "http.handlers.headers",
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New: func() caddy.Module { return new(Headers) },
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New: func() caddy.Module { return new(Handler) },
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}
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}
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// HeaderOps defines some operations to
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// perform on HTTP headers.
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type HeaderOps struct {
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Add http.Header `json:"add,omitempty"`
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Set http.Header `json:"set,omitempty"`
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Delete []string `json:"delete,omitempty"`
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// Provision sets up h's configuration.
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func (h *Handler) Provision(_ caddy.Context) error {
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if h.Request != nil {
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err := h.Request.provision()
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if err != nil {
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return err
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}
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}
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if h.Response != nil {
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err := h.Response.provision()
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if err != nil {
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return err
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}
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}
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return nil
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}
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// RespHeaderOps is like HeaderOps, but
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// optionally deferred until response time.
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type RespHeaderOps struct {
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*HeaderOps
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Require *caddyhttp.ResponseMatcher `json:"require,omitempty"`
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Deferred bool `json:"deferred,omitempty"`
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// Validate ensures h's configuration is valid.
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func (h Handler) Validate() error {
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if h.Request != nil {
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err := h.Request.validate()
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if err != nil {
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return err
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}
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}
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if h.Response != nil {
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err := h.Response.validate()
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (h Headers) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
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func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
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repl := r.Context().Value(caddy.ReplacerCtxKey).(caddy.Replacer)
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apply(h.Request, r.Header, repl)
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h.Request.applyTo(r.Header, repl)
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// request header's Host is handled specially by the
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// Go standard library, so if that header was changed,
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@ -79,22 +99,79 @@ func (h Headers) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhtt
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headerOps: h.Response.HeaderOps,
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}
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} else {
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apply(h.Response.HeaderOps, w.Header(), repl)
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h.Response.applyTo(w.Header(), repl)
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}
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}
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return next.ServeHTTP(w, r)
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}
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func apply(ops *HeaderOps, hdr http.Header, repl caddy.Replacer) {
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// HeaderOps defines some operations to
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// perform on HTTP headers.
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type HeaderOps struct {
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Add http.Header `json:"add,omitempty"`
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Set http.Header `json:"set,omitempty"`
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Delete []string `json:"delete,omitempty"`
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Replace map[string][]Replacement `json:"replace,omitempty"`
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}
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func (ops *HeaderOps) provision() error {
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for fieldName, replacements := range ops.Replace {
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for i, r := range replacements {
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if r.SearchRegexp != "" {
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re, err := regexp.Compile(r.SearchRegexp)
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if err != nil {
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return fmt.Errorf("replacement %d for header field '%s': %v", i, fieldName, err)
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}
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replacements[i].re = re
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}
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}
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}
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return nil
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}
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func (ops HeaderOps) validate() error {
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for fieldName, replacements := range ops.Replace {
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for _, r := range replacements {
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if r.Search != "" && r.SearchRegexp != "" {
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return fmt.Errorf("cannot specify both a substring search and a regular expression search for field '%s'", fieldName)
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}
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}
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}
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return nil
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}
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// Replacement describes a string replacement,
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// either a simple and fast sugbstring search
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// or a slower but more powerful regex search.
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type Replacement struct {
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Search string `json:"search,omitempty"`
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SearchRegexp string `json:"search_regexp,omitempty"`
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Replace string `json:"replace,omitempty"`
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re *regexp.Regexp
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}
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// RespHeaderOps is like HeaderOps, but
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// optionally deferred until response time.
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type RespHeaderOps struct {
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*HeaderOps
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Require *caddyhttp.ResponseMatcher `json:"require,omitempty"`
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Deferred bool `json:"deferred,omitempty"`
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}
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func (ops *HeaderOps) applyTo(hdr http.Header, repl caddy.Replacer) {
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if ops == nil {
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return
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}
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for fieldName, vals := range ops.Add {
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fieldName = repl.ReplaceAll(fieldName, "")
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for _, v := range vals {
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hdr.Add(fieldName, repl.ReplaceAll(v, ""))
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}
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}
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for fieldName, vals := range ops.Set {
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fieldName = repl.ReplaceAll(fieldName, "")
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for i := range vals {
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@ -102,9 +179,45 @@ func apply(ops *HeaderOps, hdr http.Header, repl caddy.Replacer) {
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}
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hdr.Set(fieldName, strings.Join(vals, ","))
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}
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for _, fieldName := range ops.Delete {
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hdr.Del(repl.ReplaceAll(fieldName, ""))
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}
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for fieldName, replacements := range ops.Replace {
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fieldName = repl.ReplaceAll(fieldName, "")
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// perform replacements across all fields
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if fieldName == "*" {
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for _, r := range replacements {
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search := repl.ReplaceAll(r.Search, "")
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replace := repl.ReplaceAll(r.Replace, "")
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for fieldName, vals := range hdr {
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for i := range vals {
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if r.re != nil {
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hdr[fieldName][i] = r.re.ReplaceAllString(hdr[fieldName][i], replace)
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} else {
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hdr[fieldName][i] = strings.ReplaceAll(hdr[fieldName][i], search, replace)
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}
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}
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}
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}
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continue
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}
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// perform replacements only with the named field
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for _, r := range replacements {
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search := repl.ReplaceAll(r.Search, "")
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replace := repl.ReplaceAll(r.Replace, "")
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for i := range hdr[fieldName] {
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if r.re != nil {
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hdr[fieldName][i] = r.re.ReplaceAllString(hdr[fieldName][i], replace)
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} else {
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hdr[fieldName][i] = strings.ReplaceAll(hdr[fieldName][i], search, replace)
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}
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}
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}
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}
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}
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// responseWriterWrapper defers response header
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@ -123,7 +236,7 @@ func (rww *responseWriterWrapper) WriteHeader(status int) {
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}
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rww.wroteHeader = true
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if rww.require == nil || rww.require.Match(status, rww.ResponseWriterWrapper.Header()) {
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apply(rww.headerOps, rww.ResponseWriterWrapper.Header(), rww.replacer)
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rww.headerOps.applyTo(rww.ResponseWriterWrapper.Header(), rww.replacer)
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}
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rww.ResponseWriterWrapper.WriteHeader(status)
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}
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@ -137,6 +250,7 @@ func (rww *responseWriterWrapper) Write(d []byte) (int, error) {
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// Interface guards
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var (
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_ caddyhttp.MiddlewareHandler = (*Headers)(nil)
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_ caddy.Provisioner = (*Handler)(nil)
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_ caddyhttp.MiddlewareHandler = (*Handler)(nil)
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_ caddyhttp.HTTPInterfaces = (*responseWriterWrapper)(nil)
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)
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