package addprefix import ( "context" "fmt" "net/http" "github.com/opentracing/opentracing-go/ext" "github.com/traefik/traefik/v2/pkg/config/dynamic" "github.com/traefik/traefik/v2/pkg/middlewares" "github.com/traefik/traefik/v2/pkg/tracing" ) const ( typeName = "AddPrefix" ) // AddPrefix is a middleware used to add prefix to an URL request. type addPrefix struct { next http.Handler prefix string name string } // New creates a new handler. func New(ctx context.Context, next http.Handler, config dynamic.AddPrefix, name string) (http.Handler, error) { middlewares.GetLogger(ctx, name, typeName).Debug().Msg("Creating middleware") var result *addPrefix if len(config.Prefix) > 0 { result = &addPrefix{ prefix: config.Prefix, next: next, name: name, } } else { return nil, fmt.Errorf("prefix cannot be empty") } return result, nil } func (a *addPrefix) GetTracingInformation() (string, ext.SpanKindEnum) { return a.name, tracing.SpanKindNoneEnum } func (a *addPrefix) ServeHTTP(rw http.ResponseWriter, req *http.Request) { logger := middlewares.GetLogger(req.Context(), a.name, typeName) oldURLPath := req.URL.Path req.URL.Path = ensureLeadingSlash(a.prefix + req.URL.Path) logger.Debug().Msgf("URL.Path is now %s (was %s).", req.URL.Path, oldURLPath) if req.URL.RawPath != "" { oldURLRawPath := req.URL.RawPath req.URL.RawPath = ensureLeadingSlash(a.prefix + req.URL.RawPath) logger.Debug().Msgf("URL.RawPath is now %s (was %s).", req.URL.RawPath, oldURLRawPath) } req.RequestURI = req.URL.RequestURI() a.next.ServeHTTP(rw, req) } func ensureLeadingSlash(str string) string { if str == "" { return str } if str[0] == '/' { return str } return "/" + str }