Dynamic Configuration Refactoring

middlewares/headers/headers.go

@@ -0,0 +1,134 @@
+// Package headers Middleware based on https://github.com/unrolled/secure.
+package headers
+
+import (
+	"context"
+	"errors"
+	"net/http"
+
+	"github.com/containous/traefik/config"
+	"github.com/containous/traefik/middlewares"
+	"github.com/containous/traefik/tracing"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/unrolled/secure"
+)
+
+const (
+	typeName = "Headers"
+)
+
+type headers struct {
+	name    string
+	handler http.Handler
+}
+
+// New creates a Headers middleware.
+func New(ctx context.Context, next http.Handler, config config.Headers, name string) (http.Handler, error) {
+	// HeaderMiddleware -> SecureMiddleWare -> next
+	logger := middlewares.GetLogger(ctx, name, typeName)
+	logger.Debug("Creating middleware")
+
+	if !config.HasSecureHeadersDefined() && !config.HasCustomHeadersDefined() {
+		return nil, errors.New("headers configuration not valid")
+	}
+
+	var handler http.Handler
+	nextHandler := next
+
+	if config.HasSecureHeadersDefined() {
+		logger.Debug("Setting up secureHeaders from %v", config)
+		handler = newSecure(next, config)
+		nextHandler = handler
+	}
+
+	if config.HasCustomHeadersDefined() {
+		logger.Debug("Setting up customHeaders from %v", config)
+		handler = newHeader(nextHandler, config)
+	}
+
+	return &headers{
+		handler: handler,
+		name:    name,
+	}, nil
+}
+
+func (h *headers) GetTracingInformation() (string, ext.SpanKindEnum) {
+	return h.name, tracing.SpanKindNoneEnum
+}
+
+func (h *headers) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	h.handler.ServeHTTP(rw, req)
+}
+
+type secureHeader struct {
+	next   http.Handler
+	secure *secure.Secure
+}
+
+// newSecure constructs a new secure instance with supplied options.
+func newSecure(next http.Handler, headers config.Headers) *secureHeader {
+	opt := secure.Options{
+		BrowserXssFilter:        headers.BrowserXSSFilter,
+		ContentTypeNosniff:      headers.ContentTypeNosniff,
+		ForceSTSHeader:          headers.ForceSTSHeader,
+		FrameDeny:               headers.FrameDeny,
+		IsDevelopment:           headers.IsDevelopment,
+		SSLRedirect:             headers.SSLRedirect,
+		SSLForceHost:            headers.SSLForceHost,
+		SSLTemporaryRedirect:    headers.SSLTemporaryRedirect,
+		STSIncludeSubdomains:    headers.STSIncludeSubdomains,
+		STSPreload:              headers.STSPreload,
+		ContentSecurityPolicy:   headers.ContentSecurityPolicy,
+		CustomBrowserXssValue:   headers.CustomBrowserXSSValue,
+		CustomFrameOptionsValue: headers.CustomFrameOptionsValue,
+		PublicKey:               headers.PublicKey,
+		ReferrerPolicy:          headers.ReferrerPolicy,
+		SSLHost:                 headers.SSLHost,
+		AllowedHosts:            headers.AllowedHosts,
+		HostsProxyHeaders:       headers.HostsProxyHeaders,
+		SSLProxyHeaders:         headers.SSLProxyHeaders,
+		STSSeconds:              headers.STSSeconds,
+	}
+
+	return &secureHeader{
+		next:   next,
+		secure: secure.New(opt),
+	}
+}
+
+func (s secureHeader) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	s.secure.HandlerFuncWithNextForRequestOnly(rw, req, s.next.ServeHTTP)
+}
+
+// Header is a middleware that helps setup a few basic security features. A single headerOptions struct can be
+// provided to configure which features should be enabled, and the ability to override a few of the default values.
+type header struct {
+	next http.Handler
+	// If Custom request headers are set, these will be added to the request
+	customRequestHeaders map[string]string
+}
+
+// NewHeader constructs a new header instance from supplied frontend header struct.
+func newHeader(next http.Handler, headers config.Headers) *header {
+	return &header{
+		next:                 next,
+		customRequestHeaders: headers.CustomRequestHeaders,
+	}
+}
+
+func (s *header) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	s.modifyRequestHeaders(req)
+	s.next.ServeHTTP(rw, req)
+}
+
+// modifyRequestHeaders set or delete request headers.
+func (s *header) modifyRequestHeaders(req *http.Request) {
+	// Loop through Custom request headers
+	for header, value := range s.customRequestHeaders {
+		if value == "" {
+			req.Header.Del(header)
+		} else {
+			req.Header.Set(header, value)
+		}
+	}
+}