80 lines
2.3 KiB
Go
80 lines
2.3 KiB
Go
package replacepathregex
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import (
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"context"
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"fmt"
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"net/http"
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"net/url"
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"regexp"
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"strings"
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"github.com/opentracing/opentracing-go/ext"
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"github.com/traefik/traefik/v2/pkg/config/dynamic"
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"github.com/traefik/traefik/v2/pkg/log"
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"github.com/traefik/traefik/v2/pkg/middlewares"
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"github.com/traefik/traefik/v2/pkg/middlewares/replacepath"
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"github.com/traefik/traefik/v2/pkg/tracing"
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)
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const (
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typeName = "ReplacePathRegex"
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)
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// ReplacePathRegex is a middleware used to replace the path of a URL request with a regular expression.
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type replacePathRegex struct {
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next http.Handler
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regexp *regexp.Regexp
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replacement string
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name string
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}
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// New creates a new replace path regex middleware.
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func New(ctx context.Context, next http.Handler, config dynamic.ReplacePathRegex, name string) (http.Handler, error) {
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log.FromContext(middlewares.GetLoggerCtx(ctx, name, typeName)).Debug("Creating middleware")
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exp, err := regexp.Compile(strings.TrimSpace(config.Regex))
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if err != nil {
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return nil, fmt.Errorf("error compiling regular expression %s: %w", config.Regex, err)
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}
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return &replacePathRegex{
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regexp: exp,
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replacement: strings.TrimSpace(config.Replacement),
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next: next,
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name: name,
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}, nil
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}
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func (rp *replacePathRegex) GetTracingInformation() (string, ext.SpanKindEnum) {
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return rp.name, tracing.SpanKindNoneEnum
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}
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func (rp *replacePathRegex) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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var currentPath string
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if req.URL.RawPath == "" {
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currentPath = req.URL.Path
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} else {
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currentPath = req.URL.RawPath
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}
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if rp.regexp != nil && len(rp.replacement) > 0 && rp.regexp.MatchString(currentPath) {
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req.Header.Add(replacepath.ReplacedPathHeader, currentPath)
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req.URL.RawPath = rp.regexp.ReplaceAllString(currentPath, rp.replacement)
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// as replacement can introduce escaped characters
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// Path must remain an unescaped version of RawPath
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// Doesn't handle multiple times encoded replacement (`/` => `%2F` => `%252F` => ...)
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var err error
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req.URL.Path, err = url.PathUnescape(req.URL.RawPath)
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if err != nil {
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log.FromContext(middlewares.GetLoggerCtx(context.Background(), rp.name, typeName)).Error(err)
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http.Error(rw, err.Error(), http.StatusInternalServerError)
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return
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}
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req.RequestURI = req.URL.RequestURI()
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}
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rp.next.ServeHTTP(rw, req)
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}
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