52 lines
1.4 KiB
Go
52 lines
1.4 KiB
Go
package server
|
|
|
|
import (
|
|
"net/http"
|
|
"net/url"
|
|
"path"
|
|
"strings"
|
|
)
|
|
|
|
type interceptingResponseWriter struct {
|
|
http.ResponseWriter
|
|
Flusher http.Flusher
|
|
Prefix string
|
|
}
|
|
|
|
func (i *interceptingResponseWriter) WriteHeader(status int) {
|
|
if status >= 300 && status < 400 {
|
|
location := i.ResponseWriter.Header().Get("Location")
|
|
if u, err := url.Parse(location); err == nil && !u.IsAbs() {
|
|
hasPrefix := strings.HasPrefix(u.Path, i.Prefix)
|
|
if !hasPrefix || (hasPrefix && !strings.HasPrefix(u.Path[len(i.Prefix):], i.Prefix)) {
|
|
i.ResponseWriter.Header().Set("Location", path.Join(i.Prefix, location)+"/")
|
|
}
|
|
}
|
|
}
|
|
i.ResponseWriter.WriteHeader(status)
|
|
}
|
|
|
|
// Flush is here because the underlying HTTP chunked transfer response writer
|
|
// to implement http.Flusher. Without it data is silently buffered. This
|
|
// was discovered when proxying kapacitor chunked logs.
|
|
func (i *interceptingResponseWriter) Flush() {
|
|
if i.Flusher != nil {
|
|
i.Flusher.Flush()
|
|
}
|
|
}
|
|
|
|
// PrefixedRedirect alters the Location header of downstream http.Handlers
|
|
// to include a specified prefix
|
|
func PrefixedRedirect(prefix string, next http.Handler) http.Handler {
|
|
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
|
iw := &interceptingResponseWriter{
|
|
ResponseWriter: w,
|
|
Prefix: prefix,
|
|
}
|
|
if flusher, ok := w.(http.Flusher); ok {
|
|
iw.Flusher = flusher
|
|
}
|
|
next.ServeHTTP(iw, r)
|
|
})
|
|
}
|