Update api with registering handlers, middleware and authentication

api/authentication.go

@@ -0,0 +1,110 @@
+package api
+
+import (
+	"encoding/base64"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/safing/portbase/crypto/random"
+	"github.com/safing/portbase/log"
+)
+
+var (
+	validTokens     map[string]time.Time
+	validTokensLock sync.Mutex
+
+	authFnLock sync.Mutex
+	authFn     Authenticator
+)
+
+const (
+	cookieName = "T17"
+
+	// in seconds
+	cookieBaseTTL = 300 // 5 minutes
+	cookieTTL     = cookieBaseTTL * time.Second
+	cookieRefresh = cookieBaseTTL * 0.9 * time.Second
+)
+
+// Authenticator is a function that can be set as the authenticator for the API endpoint. If none is set, all requests will be allowed.
+type Authenticator func(s *http.Server, r *http.Request) (grantAccess bool, err error)
+
+// SetAuthenticator sets an authenticator function for the API endpoint. If none is set, all requests will be allowed.
+func SetAuthenticator(fn Authenticator) error {
+	authFnLock.Lock()
+	defer authFnLock.Unlock()
+
+	if authFn == nil {
+		authFn = fn
+		return nil
+	}
+
+	return ErrAuthenticationAlreadySet
+}
+
+func authMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+
+		// check existing auth cookie
+		c, err := r.Cookie(cookieName)
+		if err == nil {
+			// get token
+			validTokensLock.Lock()
+			validUntil, valid := validTokens[c.Value]
+			validTokensLock.Unlock()
+
+			// check if token is valid
+			if valid && time.Now().Before(validUntil) {
+				// maybe refresh cookie
+				if time.Now().After(validUntil.Add(-cookieRefresh)) {
+					validTokensLock.Lock()
+					validTokens[c.Value] = time.Now()
+					validTokensLock.Unlock()
+				}
+				next.ServeHTTP(w, r)
+				return
+			}
+		}
+
+		// get authenticator
+		authFnLock.Lock()
+		authenticator := authFn
+		authFnLock.Unlock()
+
+		// permit if no authenticator set
+		if authenticator == nil {
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		// get auth decision
+		grantAccess, err := authenticator(server, r)
+		if err != nil {
+			log.Errorf("api: authenticator failed: %s", err)
+			http.Error(w, "", http.StatusInternalServerError)
+		}
+		if !grantAccess {
+			log.Warningf("api: denying api access to %s", r.RemoteAddr)
+			http.Error(w, "", http.StatusForbidden)
+			return
+		}
+
+		// write new cookie
+		token, err := random.Bytes(32) // 256 bit
+		if err != nil {
+			log.Errorf("api: failed to generate random token: %s", err)
+			http.Error(w, "", http.StatusInternalServerError)
+		}
+		tokenString := base64.RawURLEncoding.EncodeToString(token)
+		http.SetCookie(w, &http.Cookie{
+			Name:     cookieName,
+			Value:    tokenString,
+			HttpOnly: true,
+		})
+
+		// serve
+		log.Tracef("api: granted %s", r.RemoteAddr)
+		next.ServeHTTP(w, r)
+	})
+}

api/config.go

@@ -24,7 +24,7 @@ func checkFlags() error {
 	return nil
 }
 
-func getListenAddress() string {
+func GetAPIAddress() string {
 	if listenAddressFlag != "" {
 		return listenAddressFlag
 	}
@@ -49,6 +49,7 @@ func registerConfig() error {
 	return nil
 }
 
+// SetDefaultAPIListenAddress sets the default listen address for the API.
 func SetDefaultAPIListenAddress(address string) {
 	if defaultListenAddress == "" {
 		defaultListenAddress = address

api/database.go

@@ -35,6 +35,10 @@ var (
 	dbAPISeperatorBytes = []byte(dbAPISeperator)
 )
 
+func init() {
+	RegisterHandleFunc("/api/database/v1", startDatabaseAPI) // net/http pattern matching only this exact path
+}
+
 // DatabaseAPI is a database API instance.
 type DatabaseAPI struct {
 	conn      *websocket.Conn

api/enriched-response.go

@@ -1,25 +1,68 @@
 package api
 
 import (
+	"bufio"
+	"errors"
+	"net"
 	"net/http"
+
+	"github.com/safing/portbase/log"
 )
 
-// EnrichedResponseWriter is a wrapper for http.ResponseWriter for better information extraction.
-type EnrichedResponseWriter struct {
-	http.ResponseWriter
+// LoggingResponseWriter is a wrapper for http.ResponseWriter for better request logging.
+type LoggingResponseWriter struct {
+	ResponseWriter http.ResponseWriter
+	Request        *http.Request
 	Status         int
 }
 
-// NewEnrichedResponseWriter wraps a http.ResponseWriter.
-func NewEnrichedResponseWriter(w http.ResponseWriter) *EnrichedResponseWriter {
-	return &EnrichedResponseWriter{
-		w,
-		0,
+// NewLoggingResponseWriter wraps a http.ResponseWriter.
+func NewLoggingResponseWriter(w http.ResponseWriter, r *http.Request) *LoggingResponseWriter {
+	return &LoggingResponseWriter{
+		ResponseWriter: w,
+		Request:        r,
 	}
 }
 
-// WriteHeader wraps the original WriteHeader method to extract information.
-func (ew *EnrichedResponseWriter) WriteHeader(code int) {
-	ew.Status = code
-	ew.ResponseWriter.WriteHeader(code)
+// Header wraps the original Header method.
+func (lrw *LoggingResponseWriter) Header() http.Header {
+	return lrw.ResponseWriter.Header()
+}
+
+// Write wraps the original Write method.
+func (lrw *LoggingResponseWriter) Write(b []byte) (int, error) {
+	return lrw.ResponseWriter.Write(b)
+}
+
+// WriteHeader wraps the original WriteHeader method to extract information.
+func (lrw *LoggingResponseWriter) WriteHeader(code int) {
+	lrw.Status = code
+	lrw.ResponseWriter.WriteHeader(code)
+}
+
+// Hijack wraps the original Hijack method, if available.
+func (lrw *LoggingResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	hijacker, ok := lrw.ResponseWriter.(http.Hijacker)
+	if ok {
+		c, b, err := hijacker.Hijack()
+		if err != nil {
+			return nil, nil, err
+		}
+		log.Infof("api request: %s HIJ %s", lrw.Request.RemoteAddr, lrw.Request.RequestURI)
+		return c, b, nil
+	}
+	return nil, nil, errors.New("response does not implement http.Hijacker")
+}
+
+// RequestLogger is a logging middleware
+func RequestLogger(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		log.Tracef("api request: %s ___ %s", r.RemoteAddr, r.RequestURI)
+		lrw := NewLoggingResponseWriter(w, r)
+		next.ServeHTTP(lrw, r)
+		if lrw.Status != 0 {
+			// request may have been hijacked
+			log.Infof("api request: %s %d %s", lrw.Request.RemoteAddr, lrw.Status, lrw.Request.RequestURI)
+		}
+	})
 }

api/main.go

@@ -1,9 +1,17 @@
 package api
 
 import (
+	"context"
+	"errors"
+
 	"github.com/safing/portbase/modules"
 )
 
+// API Errors
+var (
+	ErrAuthenticationAlreadySet = errors.New("the authentication function has already been set")
+)
+
 func init() {
 	modules.Register("api", prep, start, nil, "database")
 }
@@ -20,3 +28,10 @@ func start() error {
 	go Serve()
 	return nil
 }
+
+func stop() error {
+	if server != nil {
+		return server.Shutdown(context.Background())
+	}
+	return nil
+}

api/middleware.go

@@ -0,0 +1,27 @@
+package api
+
+import "net/http"
+
+// Middleware is a function that can be added as a middleware to the API endpoint.
+type Middleware func(next http.Handler) http.Handler
+
+type mwHandler struct {
+	handlers []Middleware
+	final    http.Handler
+}
+
+func (mwh *mwHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	handlerLock.RLock()
+	defer handlerLock.RUnlock()
+
+	// final handler
+	handler := mwh.final
+
+	// build middleware chain
+	for _, mw := range mwh.handlers {
+		handler = mw(handler)
+	}
+
+	// start
+	handler.ServeHTTP(w, r)
+}

api/router.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"net/http"
+	"sync"
 
 	"github.com/gorilla/mux"
 
@@ -9,35 +10,54 @@ import (
 )
 
 var (
-	router = mux.NewRouter()
+	// gorilla mux
+	mainMux = mux.NewRouter()
+
+	// middlewares
+	middlewareHandler = &mwHandler{
+		final: mainMux,
+		handlers: []Middleware{
+			RequestLogger,
+			authMiddleware,
+		},
+	}
+
+	// main server and lock
+	server      = &http.Server{}
+	handlerLock sync.RWMutex
 )
 
-// RegisterHandleFunc registers an additional handle function with the API endoint.
-func RegisterHandleFunc(path string, handleFunc func(http.ResponseWriter, *http.Request)) *mux.Route {
-	return router.HandleFunc(path, handleFunc)
+// RegisterHandler registers a handler with the API endoint.
+func RegisterHandler(path string, handler http.Handler) *mux.Route {
+	handlerLock.Lock()
+	defer handlerLock.Unlock()
+	return mainMux.Handle(path, handler)
 }
 
-// RequestLogger is a logging middleware
-func RequestLogger(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		log.Tracef("api request: %s ___ %s", r.RemoteAddr, r.RequestURI)
-		ew := NewEnrichedResponseWriter(w)
-		next.ServeHTTP(ew, r)
-		log.Infof("api request: %s %d %s", r.RemoteAddr, ew.Status, r.RequestURI)
-	})
+// RegisterHandleFunc registers a handle function with the API endoint.
+func RegisterHandleFunc(path string, handleFunc func(http.ResponseWriter, *http.Request)) *mux.Route {
+	handlerLock.Lock()
+	defer handlerLock.Unlock()
+	return mainMux.HandleFunc(path, handleFunc)
+}
+
+// RegisterMiddleware registers a middle function with the API endoint.
+func RegisterMiddleware(middleware Middleware) {
+	handlerLock.Lock()
+	defer handlerLock.Unlock()
+	middlewareHandler.handlers = append(middlewareHandler.handlers, middleware)
 }
 
 // Serve starts serving the API endpoint.
 func Serve() {
-	router.Use(RequestLogger)
+	// configure server
+	server.Addr = GetAPIAddress()
+	server.Handler = middlewareHandler
 
-	mainMux := http.NewServeMux()
-	mainMux.Handle("/", router)                              // net/http pattern matching /*
-	mainMux.HandleFunc("/api/database/v1", startDatabaseAPI) // net/http pattern matching only this exact path
-
-	address := getListenAddress()
-	log.Infof("api: starting to listen on %s", address)
-	log.Errorf("api: failed to listen on %s: %s", address, http.ListenAndServe(address, mainMux))
+	// start serving
+	log.Infof("api: starting to listen on %s", server.Addr)
+	// TODO: retry if failed
+	log.Errorf("api: failed to listen on %s: %s", server.Addr, server.ListenAndServe())
 }
 
 // GetMuxVars wraps github.com/gorilla/mux.Vars in order to mitigate context key issues in multi-repo projects.

api/security.go

@@ -1 +0,0 @@
-package api

api/testclient/serve.go

@@ -7,5 +7,5 @@ import (
 )
 
 func init() {
-	api.RegisterAdditionalRoute("/test/", http.StripPrefix("/test/", http.FileServer(http.Dir("./api/testclient/root/"))))
+	api.RegisterHandler("/test/", http.StripPrefix("/test/", http.FileServer(http.Dir("./api/testclient/root/"))))
 }

api/websocket.go

@@ -1 +0,0 @@
-package api