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mmatur
128 lines
3.5 KiB
Go
128 lines
3.5 KiB
Go
package stripprefix
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import (
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"context"
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"net/http"
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"strings"
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"github.com/traefik/traefik/v3/pkg/config/dynamic"
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"github.com/traefik/traefik/v3/pkg/middlewares"
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)
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const (
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// ForwardedPrefixHeader is the default header to set prefix.
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ForwardedPrefixHeader = "X-Forwarded-Prefix"
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typeName = "StripPrefix"
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)
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// stripPrefix is a middleware used to strip prefix from an URL request.
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type stripPrefix struct {
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next http.Handler
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prefixes []string
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name string
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// Deprecated: Must be removed (breaking), the default behavior must be forceSlash=false
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forceSlash bool
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}
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// New creates a new strip prefix middleware.
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func New(ctx context.Context, next http.Handler, config dynamic.StripPrefix, name string) (http.Handler, error) {
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logger := middlewares.GetLogger(ctx, name, typeName)
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logger.Debug().Msg("Creating middleware")
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if config.ForceSlash != nil {
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logger.Warn().Msgf("`ForceSlash` option is deprecated, please remove any usage of this option.")
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}
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// Handle default value (here because of deprecation and the removal of setDefault).
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forceSlash := config.ForceSlash != nil && *config.ForceSlash
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prefixes := make([]string, len(config.Prefixes))
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for i, p := range config.Prefixes {
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prefixes[i] = strings.TrimSpace(p)
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}
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return &stripPrefix{
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prefixes: prefixes,
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next: next,
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name: name,
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forceSlash: forceSlash,
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}, nil
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}
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func (s *stripPrefix) GetTracingInformation() (string, string) {
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return s.name, typeName
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}
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func (s *stripPrefix) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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for _, prefix := range s.prefixes {
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if strings.HasPrefix(req.URL.Path, prefix) {
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req.URL.Path = s.getPathStripped(req.URL.Path, prefix)
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if req.URL.RawPath != "" {
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req.URL.RawPath = s.getRawPathStripped(req.URL.RawPath, prefix)
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}
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// Here we are sanitizing the URL when the path is not empty,
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// as the JoinPath method is adding a leading slash if the path is empty
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// to be aligned with ensureLeadingSlash behavior.
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if req.URL.Path != "" {
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req.URL = req.URL.JoinPath()
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}
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req.Header.Add(ForwardedPrefixHeader, prefix)
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req.RequestURI = req.URL.RequestURI()
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break
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}
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}
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s.next.ServeHTTP(rw, req)
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}
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func (s *stripPrefix) getPathStripped(urlPath, prefix string) string {
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if s.forceSlash {
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// Only for compatibility reason with the previous behavior,
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// but the previous behavior is wrong.
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// This needs to be removed in the next breaking version.
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return "/" + strings.TrimPrefix(strings.TrimPrefix(urlPath, prefix), "/")
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}
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return ensureLeadingSlash(strings.TrimPrefix(urlPath, prefix))
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}
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func (s *stripPrefix) getRawPathStripped(rawPath, prefix string) string {
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if s.forceSlash {
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// Only for compatibility reason with the previous behavior,
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// but the previous behavior is wrong.
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// This needs to be removed in the next breaking version.
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return "/" + strings.TrimPrefix(rawPath[encodedPrefixLen(rawPath, prefix):], "/")
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}
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return ensureLeadingSlash(rawPath[encodedPrefixLen(rawPath, prefix):])
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}
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// encodedPrefixLen returns the number of bytes in rawPath that correspond to
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// the decoded prefix, advancing 3 bytes per %XX sequence and 1 byte otherwise.
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func encodedPrefixLen(rawPath, decodedPrefix string) int {
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decoded := 0
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i := 0
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for i < len(rawPath) && decoded < len(decodedPrefix) {
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if rawPath[i] == '%' && i+2 < len(rawPath) {
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i += 3
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} else {
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i++
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}
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decoded++
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}
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return i
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}
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func ensureLeadingSlash(str string) string {
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if str == "" {
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return str
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}
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if str[0] == '/' {
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return str
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}
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return "/" + str
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}
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