package stripprefix import ( "context" "net/http" "strings" "github.com/opentracing/opentracing-go/ext" "github.com/traefik/traefik/v2/pkg/config/dynamic" "github.com/traefik/traefik/v2/pkg/log" "github.com/traefik/traefik/v2/pkg/middlewares" "github.com/traefik/traefik/v2/pkg/tracing" ) const ( // ForwardedPrefixHeader is the default header to set prefix. ForwardedPrefixHeader = "X-Forwarded-Prefix" typeName = "StripPrefix" ) // stripPrefix is a middleware used to strip prefix from an URL request. type stripPrefix struct { next http.Handler prefixes []string forceSlash bool // TODO Must be removed (breaking), the default behavior must be forceSlash=false name string } // New creates a new strip prefix middleware. func New(ctx context.Context, next http.Handler, config dynamic.StripPrefix, name string) (http.Handler, error) { log.FromContext(middlewares.GetLoggerCtx(ctx, name, typeName)).Debug("Creating middleware") return &stripPrefix{ prefixes: config.Prefixes, forceSlash: config.ForceSlash, next: next, name: name, }, nil } func (s *stripPrefix) GetTracingInformation() (string, ext.SpanKindEnum) { return s.name, tracing.SpanKindNoneEnum } func (s *stripPrefix) ServeHTTP(rw http.ResponseWriter, req *http.Request) { for _, prefix := range s.prefixes { if strings.HasPrefix(req.URL.Path, prefix) { req.URL.Path = s.getPrefixStripped(req.URL.Path, prefix) if req.URL.RawPath != "" { req.URL.RawPath = s.getPrefixStripped(req.URL.RawPath, prefix) } s.serveRequest(rw, req, strings.TrimSpace(prefix)) return } } s.next.ServeHTTP(rw, req) } func (s *stripPrefix) serveRequest(rw http.ResponseWriter, req *http.Request, prefix string) { req.Header.Add(ForwardedPrefixHeader, prefix) req.RequestURI = req.URL.RequestURI() s.next.ServeHTTP(rw, req) } func (s *stripPrefix) getPrefixStripped(urlPath, prefix string) string { if s.forceSlash { // Only for compatibility reason with the previous behavior, // but the previous behavior is wrong. // This needs to be removed in the next breaking version. return "/" + strings.TrimPrefix(strings.TrimPrefix(urlPath, prefix), "/") } return ensureLeadingSlash(strings.TrimPrefix(urlPath, prefix)) } func ensureLeadingSlash(str string) string { if str == "" { return str } if str[0] == '/' { return str } return "/" + str }