Dynamic Configuration Refactoring

old/middlewares/auth/forward.go

@@ -0,0 +1,157 @@
+package auth
+
+import (
+	"io/ioutil"
+	"net"
+	"net/http"
+	"strings"
+
+	"github.com/containous/traefik/old/log"
+	"github.com/containous/traefik/old/middlewares/tracing"
+	"github.com/containous/traefik/old/types"
+	"github.com/vulcand/oxy/forward"
+	"github.com/vulcand/oxy/utils"
+)
+
+const (
+	xForwardedURI    = "X-Forwarded-Uri"
+	xForwardedMethod = "X-Forwarded-Method"
+)
+
+// Forward the authentication to a external server
+func Forward(config *types.Forward, w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
+	// Ensure our request client does not follow redirects
+	httpClient := http.Client{
+		CheckRedirect: func(r *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+
+	if config.TLS != nil {
+		tlsConfig, err := config.TLS.CreateTLSConfig()
+		if err != nil {
+			tracing.SetErrorAndDebugLog(r, "Unable to configure TLS to call %s. Cause %s", config.Address, err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		httpClient.Transport = &http.Transport{
+			TLSClientConfig: tlsConfig,
+		}
+	}
+
+	forwardReq, err := http.NewRequest(http.MethodGet, config.Address, http.NoBody)
+	tracing.LogRequest(tracing.GetSpan(r), forwardReq)
+	if err != nil {
+		tracing.SetErrorAndDebugLog(r, "Error calling %s. Cause %s", config.Address, err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	writeHeader(r, forwardReq, config.TrustForwardHeader)
+
+	tracing.InjectRequestHeaders(forwardReq)
+
+	forwardResponse, forwardErr := httpClient.Do(forwardReq)
+	if forwardErr != nil {
+		tracing.SetErrorAndDebugLog(r, "Error calling %s. Cause: %s", config.Address, forwardErr)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	body, readError := ioutil.ReadAll(forwardResponse.Body)
+	if readError != nil {
+		tracing.SetErrorAndDebugLog(r, "Error reading body %s. Cause: %s", config.Address, readError)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	defer forwardResponse.Body.Close()
+
+	// Pass the forward response's body and selected headers if it
+	// didn't return a response within the range of [200, 300).
+	if forwardResponse.StatusCode < http.StatusOK || forwardResponse.StatusCode >= http.StatusMultipleChoices {
+		log.Debugf("Remote error %s. StatusCode: %d", config.Address, forwardResponse.StatusCode)
+
+		utils.CopyHeaders(w.Header(), forwardResponse.Header)
+		utils.RemoveHeaders(w.Header(), forward.HopHeaders...)
+
+		// Grab the location header, if any.
+		redirectURL, err := forwardResponse.Location()
+
+		if err != nil {
+			if err != http.ErrNoLocation {
+				tracing.SetErrorAndDebugLog(r, "Error reading response location header %s. Cause: %s", config.Address, err)
+				w.WriteHeader(http.StatusInternalServerError)
+				return
+			}
+		} else if redirectURL.String() != "" {
+			// Set the location in our response if one was sent back.
+			w.Header().Set("Location", redirectURL.String())
+		}
+
+		tracing.LogResponseCode(tracing.GetSpan(r), forwardResponse.StatusCode)
+		w.WriteHeader(forwardResponse.StatusCode)
+
+		if _, err = w.Write(body); err != nil {
+			log.Error(err)
+		}
+		return
+	}
+
+	for _, headerName := range config.AuthResponseHeaders {
+		r.Header.Set(headerName, forwardResponse.Header.Get(headerName))
+	}
+
+	r.RequestURI = r.URL.RequestURI()
+	next(w, r)
+}
+
+func writeHeader(req *http.Request, forwardReq *http.Request, trustForwardHeader bool) {
+	utils.CopyHeaders(forwardReq.Header, req.Header)
+	utils.RemoveHeaders(forwardReq.Header, forward.HopHeaders...)
+
+	if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
+		if trustForwardHeader {
+			if prior, ok := req.Header[forward.XForwardedFor]; ok {
+				clientIP = strings.Join(prior, ", ") + ", " + clientIP
+			}
+		}
+		forwardReq.Header.Set(forward.XForwardedFor, clientIP)
+	}
+
+	if xMethod := req.Header.Get(xForwardedMethod); xMethod != "" && trustForwardHeader {
+		forwardReq.Header.Set(xForwardedMethod, xMethod)
+	} else if req.Method != "" {
+		forwardReq.Header.Set(xForwardedMethod, req.Method)
+	} else {
+		forwardReq.Header.Del(xForwardedMethod)
+	}
+
+	if xfp := req.Header.Get(forward.XForwardedProto); xfp != "" && trustForwardHeader {
+		forwardReq.Header.Set(forward.XForwardedProto, xfp)
+	} else if req.TLS != nil {
+		forwardReq.Header.Set(forward.XForwardedProto, "https")
+	} else {
+		forwardReq.Header.Set(forward.XForwardedProto, "http")
+	}
+
+	if xfp := req.Header.Get(forward.XForwardedPort); xfp != "" && trustForwardHeader {
+		forwardReq.Header.Set(forward.XForwardedPort, xfp)
+	}
+
+	if xfh := req.Header.Get(forward.XForwardedHost); xfh != "" && trustForwardHeader {
+		forwardReq.Header.Set(forward.XForwardedHost, xfh)
+	} else if req.Host != "" {
+		forwardReq.Header.Set(forward.XForwardedHost, req.Host)
+	} else {
+		forwardReq.Header.Del(forward.XForwardedHost)
+	}
+
+	if xfURI := req.Header.Get(xForwardedURI); xfURI != "" && trustForwardHeader {
+		forwardReq.Header.Set(xForwardedURI, xfURI)
+	} else if req.URL.RequestURI() != "" {
+		forwardReq.Header.Set(xForwardedURI, req.URL.RequestURI())
+	} else {
+		forwardReq.Header.Del(xForwardedURI)
+	}
+}