291 lines
8.9 KiB
Go
291 lines
8.9 KiB
Go
package auth
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net"
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"net/http"
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"regexp"
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"strings"
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"time"
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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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"github.com/traefik/traefik/v3/pkg/middlewares/connectionheader"
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"github.com/traefik/traefik/v3/pkg/tracing"
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"github.com/vulcand/oxy/v2/forward"
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"github.com/vulcand/oxy/v2/utils"
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"go.opentelemetry.io/otel/trace"
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)
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const (
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xForwardedURI = "X-Forwarded-Uri"
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xForwardedMethod = "X-Forwarded-Method"
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)
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const typeNameForward = "ForwardAuth"
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// hopHeaders Hop-by-hop headers to be removed in the authentication request.
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// http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
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// Proxy-Authorization header is forwarded to the authentication server (see https://tools.ietf.org/html/rfc7235#section-4.4).
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var hopHeaders = []string{
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forward.Connection,
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forward.KeepAlive,
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forward.Te, // canonicalized version of "TE"
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forward.Trailers,
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forward.TransferEncoding,
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forward.Upgrade,
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}
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type forwardAuth struct {
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address string
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authResponseHeaders []string
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authResponseHeadersRegex *regexp.Regexp
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next http.Handler
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name string
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client http.Client
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trustForwardHeader bool
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authRequestHeaders []string
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}
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// NewForward creates a forward auth middleware.
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func NewForward(ctx context.Context, next http.Handler, config dynamic.ForwardAuth, name string) (http.Handler, error) {
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middlewares.GetLogger(ctx, name, typeNameForward).Debug().Msg("Creating middleware")
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fa := &forwardAuth{
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address: config.Address,
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authResponseHeaders: config.AuthResponseHeaders,
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next: next,
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name: name,
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trustForwardHeader: config.TrustForwardHeader,
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authRequestHeaders: config.AuthRequestHeaders,
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}
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// Ensure our request client does not follow redirects
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fa.client = http.Client{
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CheckRedirect: func(r *http.Request, via []*http.Request) error {
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return http.ErrUseLastResponse
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},
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Timeout: 30 * time.Second,
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}
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if config.TLS != nil {
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tlsConfig, err := config.TLS.CreateTLSConfig(ctx)
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if err != nil {
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return nil, fmt.Errorf("unable to create client TLS configuration: %w", err)
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}
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tr := http.DefaultTransport.(*http.Transport).Clone()
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tr.TLSClientConfig = tlsConfig
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fa.client.Transport = tr
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}
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if config.AuthResponseHeadersRegex != "" {
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re, err := regexp.Compile(config.AuthResponseHeadersRegex)
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if err != nil {
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return nil, fmt.Errorf("error compiling regular expression %s: %w", config.AuthResponseHeadersRegex, err)
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}
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fa.authResponseHeadersRegex = re
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}
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return fa, nil
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}
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func (fa *forwardAuth) GetTracingInformation() (string, string, trace.SpanKind) {
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return fa.name, typeNameForward, trace.SpanKindInternal
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}
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func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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logger := middlewares.GetLogger(req.Context(), fa.name, typeNameForward)
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req = connectionheader.Remove(req)
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forwardReq, err := http.NewRequestWithContext(req.Context(), http.MethodGet, fa.address, nil)
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if err != nil {
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logMessage := fmt.Sprintf("Error calling %s. Cause %s", fa.address, err)
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logger.Debug().Msg(logMessage)
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tracing.SetStatusErrorf(req.Context(), logMessage)
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rw.WriteHeader(http.StatusInternalServerError)
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return
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}
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var forwardSpan trace.Span
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if tracer := tracing.TracerFromContext(req.Context()); tracer != nil {
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var tracingCtx context.Context
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tracingCtx, forwardSpan = tracer.Start(req.Context(), "AuthRequest", trace.WithSpanKind(trace.SpanKindClient))
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defer forwardSpan.End()
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forwardReq = forwardReq.WithContext(tracingCtx)
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tracing.InjectContextIntoCarrier(forwardReq)
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tracing.LogClientRequest(forwardSpan, forwardReq)
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}
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writeHeader(req, forwardReq, fa.trustForwardHeader, fa.authRequestHeaders)
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forwardResponse, forwardErr := fa.client.Do(forwardReq)
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if forwardErr != nil {
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logMessage := fmt.Sprintf("Error calling %s. Cause: %s", fa.address, forwardErr)
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logger.Debug().Msg(logMessage)
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tracing.SetStatusErrorf(forwardReq.Context(), logMessage)
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rw.WriteHeader(http.StatusInternalServerError)
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return
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}
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defer forwardResponse.Body.Close()
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body, readError := io.ReadAll(forwardResponse.Body)
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if readError != nil {
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logMessage := fmt.Sprintf("Error reading body %s. Cause: %s", fa.address, readError)
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logger.Debug().Msg(logMessage)
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tracing.SetStatusErrorf(forwardReq.Context(), logMessage)
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rw.WriteHeader(http.StatusInternalServerError)
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return
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}
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// Ending the forward request span as soon as the response is handled.
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// If any errors happen earlier, this span will be close by the defer instruction.
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if forwardSpan != nil {
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forwardSpan.End()
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}
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// Pass the forward response's body and selected headers if it
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// didn't return a response within the range of [200, 300).
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if forwardResponse.StatusCode < http.StatusOK || forwardResponse.StatusCode >= http.StatusMultipleChoices {
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logger.Debug().Msgf("Remote error %s. StatusCode: %d", fa.address, forwardResponse.StatusCode)
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utils.CopyHeaders(rw.Header(), forwardResponse.Header)
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utils.RemoveHeaders(rw.Header(), hopHeaders...)
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// Grab the location header, if any.
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redirectURL, err := forwardResponse.Location()
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if err != nil {
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if !errors.Is(err, http.ErrNoLocation) {
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logMessage := fmt.Sprintf("Error reading response location header %s. Cause: %s", fa.address, err)
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logger.Debug().Msg(logMessage)
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tracing.SetStatusErrorf(forwardReq.Context(), logMessage)
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rw.WriteHeader(http.StatusInternalServerError)
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return
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}
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} else if redirectURL.String() != "" {
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// Set the location in our response if one was sent back.
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rw.Header().Set("Location", redirectURL.String())
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}
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tracing.LogResponseCode(forwardSpan, forwardResponse.StatusCode, trace.SpanKindClient)
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rw.WriteHeader(forwardResponse.StatusCode)
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if _, err = rw.Write(body); err != nil {
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logger.Error().Err(err).Send()
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}
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return
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}
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for _, headerName := range fa.authResponseHeaders {
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headerKey := http.CanonicalHeaderKey(headerName)
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req.Header.Del(headerKey)
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if len(forwardResponse.Header[headerKey]) > 0 {
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req.Header[headerKey] = append([]string(nil), forwardResponse.Header[headerKey]...)
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}
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}
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if fa.authResponseHeadersRegex != nil {
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for headerKey := range req.Header {
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if fa.authResponseHeadersRegex.MatchString(headerKey) {
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req.Header.Del(headerKey)
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}
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}
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for headerKey, headerValues := range forwardResponse.Header {
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if fa.authResponseHeadersRegex.MatchString(headerKey) {
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req.Header[headerKey] = append([]string(nil), headerValues...)
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}
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}
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}
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tracing.LogResponseCode(forwardSpan, forwardResponse.StatusCode, trace.SpanKindClient)
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req.RequestURI = req.URL.RequestURI()
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fa.next.ServeHTTP(rw, req)
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}
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func writeHeader(req, forwardReq *http.Request, trustForwardHeader bool, allowedHeaders []string) {
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utils.CopyHeaders(forwardReq.Header, req.Header)
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utils.RemoveHeaders(forwardReq.Header, hopHeaders...)
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forwardReq.Header = filterForwardRequestHeaders(forwardReq.Header, allowedHeaders)
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if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
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if trustForwardHeader {
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if prior, ok := req.Header[forward.XForwardedFor]; ok {
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clientIP = strings.Join(prior, ", ") + ", " + clientIP
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}
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}
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forwardReq.Header.Set(forward.XForwardedFor, clientIP)
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}
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xMethod := req.Header.Get(xForwardedMethod)
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switch {
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case xMethod != "" && trustForwardHeader:
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forwardReq.Header.Set(xForwardedMethod, xMethod)
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case req.Method != "":
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forwardReq.Header.Set(xForwardedMethod, req.Method)
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default:
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forwardReq.Header.Del(xForwardedMethod)
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}
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xfp := req.Header.Get(forward.XForwardedProto)
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switch {
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case xfp != "" && trustForwardHeader:
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forwardReq.Header.Set(forward.XForwardedProto, xfp)
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case req.TLS != nil:
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forwardReq.Header.Set(forward.XForwardedProto, "https")
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default:
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forwardReq.Header.Set(forward.XForwardedProto, "http")
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}
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if xfp := req.Header.Get(forward.XForwardedPort); xfp != "" && trustForwardHeader {
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forwardReq.Header.Set(forward.XForwardedPort, xfp)
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}
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xfh := req.Header.Get(forward.XForwardedHost)
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switch {
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case xfh != "" && trustForwardHeader:
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forwardReq.Header.Set(forward.XForwardedHost, xfh)
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case req.Host != "":
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forwardReq.Header.Set(forward.XForwardedHost, req.Host)
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default:
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forwardReq.Header.Del(forward.XForwardedHost)
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}
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xfURI := req.Header.Get(xForwardedURI)
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switch {
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case xfURI != "" && trustForwardHeader:
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forwardReq.Header.Set(xForwardedURI, xfURI)
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case req.URL.RequestURI() != "":
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forwardReq.Header.Set(xForwardedURI, req.URL.RequestURI())
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default:
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forwardReq.Header.Del(xForwardedURI)
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}
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}
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func filterForwardRequestHeaders(forwardRequestHeaders http.Header, allowedHeaders []string) http.Header {
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if len(allowedHeaders) == 0 {
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return forwardRequestHeaders
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}
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filteredHeaders := http.Header{}
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for _, headerName := range allowedHeaders {
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values := forwardRequestHeaders.Values(headerName)
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if len(values) > 0 {
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filteredHeaders[http.CanonicalHeaderKey(headerName)] = append([]string(nil), values...)
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}
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}
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return filteredHeaders
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}
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