traefik/middlewares/stripPrefix.go

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package middlewares
import (
"context"
"net/http"
"strings"
)
const (
// StripPrefixKey is the key within the request context used to
// store the stripped prefix
StripPrefixKey key = "StripPrefix"
// StripPrefixSlashKey is the key within the request context used to
// store the stripped slash
StripPrefixSlashKey key = "StripPrefixSlash"
// ForwardedPrefixHeader is the default header to set prefix
ForwardedPrefixHeader = "X-Forwarded-Prefix"
)
// StripPrefix is a middleware used to strip prefix from an URL request
type StripPrefix struct {
Handler http.Handler
Prefixes []string
}
func (s *StripPrefix) ServeHTTP(w http.ResponseWriter, r *http.Request) {
for _, prefix := range s.Prefixes {
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if strings.HasPrefix(r.URL.Path, prefix) {
trailingSlash := r.URL.Path == prefix+"/"
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r.URL.Path = stripPrefix(r.URL.Path, prefix)
if r.URL.RawPath != "" {
r.URL.RawPath = stripPrefix(r.URL.RawPath, prefix)
}
s.serveRequest(w, r, strings.TrimSpace(prefix), trailingSlash)
return
}
}
http.NotFound(w, r)
}
func (s *StripPrefix) serveRequest(w http.ResponseWriter, r *http.Request, prefix string, trailingSlash bool) {
r = r.WithContext(context.WithValue(r.Context(), StripPrefixSlashKey, trailingSlash))
r = r.WithContext(context.WithValue(r.Context(), StripPrefixKey, prefix))
r.Header.Add(ForwardedPrefixHeader, prefix)
r.RequestURI = r.URL.RequestURI()
s.Handler.ServeHTTP(w, r)
}
// SetHandler sets handler
func (s *StripPrefix) SetHandler(Handler http.Handler) {
s.Handler = Handler
}
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func stripPrefix(s, prefix string) string {
return ensureLeadingSlash(strings.TrimPrefix(s, prefix))
}
func ensureLeadingSlash(str string) string {
return "/" + strings.TrimPrefix(str, "/")
}