Add request scope middleware

pkg/middleware/scope.go

@@ -0,0 +1,39 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/justinas/alice"
+	middlewareapi "github.com/oauth2-proxy/oauth2-proxy/pkg/apis/middleware"
+)
+
+type scopeKey string
+
+// requestScopeKey uses a typed string to reduce likelihood of clasing
+// with other context keys
+const requestScopeKey scopeKey = "request-scope"
+
+func NewScope() alice.Constructor {
+	return addScope
+}
+
+// addScope injects a new request scope into the request context.
+func addScope(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		scope := &middlewareapi.RequestScope{}
+		contextWithScope := context.WithValue(req.Context(), requestScopeKey, scope)
+		requestWithScope := req.WithContext(contextWithScope)
+		next.ServeHTTP(rw, requestWithScope)
+	})
+}
+
+// GetRequestScope returns the current request scope from the given request
+func GetRequestScope(req *http.Request) *middlewareapi.RequestScope {
+	scope := req.Context().Value(requestScopeKey)
+	if scope == nil {
+		return nil
+	}
+
+	return scope.(*middlewareapi.RequestScope)
+}