Commit 0650dd71 authored by Michael Schoebel's avatar Michael Schoebel

New internal middleware

parent 7c844909
......@@ -59,6 +59,7 @@ var directiveOrder = []directive{
{"redir", setup.Redir},
{"ext", setup.Ext},
{"basicauth", setup.BasicAuth},
{"internal", setup.Internal},
{"proxy", setup.Proxy},
{"fastcgi", setup.FastCGI},
{"websocket", setup.WebSocket},
......
package setup
import (
"github.com/mholt/caddy/middleware"
"github.com/mholt/caddy/middleware/internal"
)
// Internal configures a new Internal middleware instance.
func Internal(c *Controller) (middleware.Middleware, error) {
paths, err := internalParse(c)
if err != nil {
return nil, err
}
return func(next middleware.Handler) middleware.Handler {
return internal.Internal{Next: next, Paths: paths}
}, nil
}
func internalParse(c *Controller) ([]string, error) {
var paths []string
for c.Next() {
if !c.NextArg() {
return paths, c.ArgErr()
}
paths = append(paths, c.Val())
}
return paths, nil
}
// The package internal provides a simple middleware that (a) prevents access
// to internal locations and (b) allows to return files from internal location
// by setting a special header, e.g. in a proxy response.
package internal
import (
"net/http"
"github.com/mholt/caddy/middleware"
)
// Internal middleware protects internal locations from external requests -
// but allows access from the inside by using a special HTTP header.
type Internal struct {
Next middleware.Handler
Paths []string
}
const redirectHeader string = "X-Accel-Redirect"
func isInternalRedirect(w http.ResponseWriter) bool {
return w.Header().Get(redirectHeader) != ""
}
// ServeHTTP implements the middlware.Handler interface.
func (i Internal) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
// Internal location requested? -> Not found.
for _, prefix := range i.Paths {
if middleware.Path(r.URL.Path).Matches(prefix) {
return http.StatusNotFound, nil
}
}
// Use internal response writer to ignore responses that will be
// redirected to internal locations
iw := internalResponseWriter{ResponseWriter: w}
status, err := i.Next.ServeHTTP(iw, r)
if isInternalRedirect(iw) && status < 400 {
// Redirect - adapt request URL path and send it again
// "down the chain"
r.URL.Path = iw.Header().Get(redirectHeader)
iw.ClearHeader()
status, err = i.Next.ServeHTTP(iw, r)
if isInternalRedirect(iw) {
// multiple redirects not supported
iw.ClearHeader()
return http.StatusInternalServerError, nil
}
}
return status, err
}
// internalResponseWriter wraps the underlying http.ResponseWriter and ignores
// calls to Write and WriteHeader if the response should be redirected to an
// internal location.
type internalResponseWriter struct {
http.ResponseWriter
}
// ClearHeader removes all header fields that are already set.
func (w internalResponseWriter) ClearHeader() {
for k := range w.Header() {
w.Header().Del(k)
}
}
// WriteHeader ignores the call if the response should be redirected to an
// internal location.
func (w internalResponseWriter) WriteHeader(code int) {
if !isInternalRedirect(w) && code < 400 {
w.ResponseWriter.WriteHeader(code)
}
}
// Write ignores the call if the response should be redirected to an internal
// location.
func (w internalResponseWriter) Write(b []byte) (int, error) {
if isInternalRedirect(w) {
return 0, nil
} else {
return w.ResponseWriter.Write(b)
}
}
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