From 77c172b823b64ebface655681ab0749b9d2f7081 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ra=C3=BAl=20Benencia?= <raul@thousandeyes.com>
Date: Fri, 13 Apr 2018 16:30:31 -0700
Subject: First public commit

---
 internal/handlers/middleware.go | 110 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 internal/handlers/middleware.go

(limited to 'internal/handlers/middleware.go')

diff --git a/internal/handlers/middleware.go b/internal/handlers/middleware.go
new file mode 100644
index 0000000..9525efb
--- /dev/null
+++ b/internal/handlers/middleware.go
@@ -0,0 +1,110 @@
+// Copyright 2018 ThousandEyes Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package handlers
+
+import (
+	"context"
+	"github.com/justinas/alice"
+	"net/http"
+	"regexp"
+
+	"github.com/thousandeyes/shoelaces/internal/environment"
+)
+
+// ShoelacesCtxID Shoelaces Specific Request Context ID.
+type ShoelacesCtxID int
+
+// ShoelacesEnvCtxID is the context id key for the shoelaces.Environment.
+const ShoelacesEnvCtxID ShoelacesCtxID = 0
+
+// ShoelacesEnvNameCtxID is the context ID key for the chosen environment.
+const ShoelacesEnvNameCtxID ShoelacesCtxID = 1
+
+var envRe = regexp.MustCompile(`^(:?/env\/([a-zA-Z0-9_-]+))?(\/.*)`)
+
+// environmentMiddleware Rewrites the URL in case it was an environment
+// specific and sets the environment in the context.
+func environmentMiddleware(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var reqEnv string
+		m := envRe.FindStringSubmatch(r.URL.Path)
+		if len(m) > 0 && m[2] != "" {
+			r.URL.Path = m[3]
+			reqEnv = m[2]
+		}
+		ctx := context.WithValue(r.Context(), ShoelacesEnvNameCtxID, reqEnv)
+		h.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+// loggingMiddleware adds an entry to the logger each time the HTTP service
+// receives a request.
+func loggingMiddleware(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		logger := envFromRequest(r).Logger
+
+		logger.Info("component", "http", "type", "request", "src", r.RemoteAddr, "method", r.Method, "url", r.URL)
+		h.ServeHTTP(w, r)
+	})
+}
+
+// SecureHeaders adds secure headers to the responses
+func secureHeadersMiddleware(h http.Handler) http.Handler {
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Add X-XSS-Protection header
+		w.Header().Add("X-XSS-Protection", "1; mode=block")
+
+		// Add X-Content-Type-Options header
+		w.Header().Add("X-Content-Type-Options", "nosniff")
+
+		// Prevent page from being displayed in an iframe
+		w.Header().Add("X-Frame-Options", "DENY")
+
+		// Prevent page from being displayed in an iframe
+		w.Header().Add("Content-Security-Policy", "script-src 'self'")
+
+		h.ServeHTTP(w, r)
+	})
+}
+
+// disableCacheMiddleware sets a header for disabling HTTP caching
+func disableCacheMiddleware(h http.Handler) http.Handler {
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Cache-Control", "no-cache, no-store, must-revalidate")
+
+		h.ServeHTTP(w, r)
+	})
+}
+
+// MiddlewareChain receives a Shoelaces environment and returns a chains of
+// middlewares to apply to every request.
+func MiddlewareChain(env *environment.Environment) alice.Chain {
+	// contextMiddleware sets the environment key in the request Context.
+	contextMiddleware := func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ctx := context.WithValue(r.Context(), ShoelacesEnvCtxID, env)
+			h.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+
+	return alice.New(
+		secureHeadersMiddleware,
+		disableCacheMiddleware,
+		environmentMiddleware,
+		contextMiddleware,
+		loggingMiddleware)
+}
-- 
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