traefik/pkg/middlewares/connectionheader/connectionheader.go

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package connectionheader
import (
"net/http"
"net/textproto"
"strings"
"golang.org/x/net/http/httpguts"
)
const (
connectionHeader = "Connection"
upgradeHeader = "Upgrade"
)
// Remover removes hop-by-hop headers listed in the "Connection" header.
// See RFC 7230, section 6.1.
func Remover(next http.Handler) http.HandlerFunc {
return func(rw http.ResponseWriter, req *http.Request) {
var reqUpType string
if httpguts.HeaderValuesContainsToken(req.Header[connectionHeader], upgradeHeader) {
reqUpType = req.Header.Get(upgradeHeader)
}
removeConnectionHeaders(req.Header)
if reqUpType != "" {
req.Header.Set(connectionHeader, upgradeHeader)
req.Header.Set(upgradeHeader, reqUpType)
} else {
req.Header.Del(connectionHeader)
}
next.ServeHTTP(rw, req)
}
}
func removeConnectionHeaders(h http.Header) {
for _, f := range h[connectionHeader] {
for _, sf := range strings.Split(f, ",") {
if sf = textproto.TrimString(sf); sf != "" {
h.Del(sf)
}
}
}
}