From 73bcd01cc621e0465a40eac4967d01c29d418bd7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Corn=C3=A9=20de=20Jong?=
 <5366568-cornedejong@users.noreply.gitlab.com>
Date: Sun, 26 May 2024 17:20:35 +0200
Subject: [PATCH] added route metadata with tests

---
 mux.go        |  2 ++
 route.go      | 46 +++++++++++++++++++++++++++
 route_test.go | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 136 insertions(+)

diff --git a/mux.go b/mux.go
index 24920ace..c9396e91 100644
--- a/mux.go
+++ b/mux.go
@@ -24,6 +24,8 @@ var (
 	// Do not run this function from `init()` in importable packages.
 	// Changing this value is not safe for concurrent use.
 	RegexpCompileFunc = regexp.Compile
+	// ErrMetadataKeyNotFound is returned when the specified metadata key is not present in the map
+	ErrMetadataKeyNotFound = errors.New("key not found in metadata")
 )
 
 // NewRouter returns a new router instance.
diff --git a/route.go b/route.go
index b6582dae..418e9676 100644
--- a/route.go
+++ b/route.go
@@ -24,6 +24,9 @@ type Route struct {
 	// Error resulted from building a route.
 	err error
 
+	// The meta data associated with this route
+	metadata map[any]any
+
 	// "global" reference to all named routes
 	namedRoutes map[string]*Route
 
@@ -122,6 +125,49 @@ func (r *Route) BuildOnly() *Route {
 	return r
 }
 
+// MetaData -------------------------------------------------------------------
+
+// Metadata is used to set metadata on a route
+func (r *Route) Metadata(key any, value any) *Route {
+	if r.metadata == nil {
+		r.metadata = make(map[any]any)
+	}
+
+	r.metadata[key] = value
+	return r
+}
+
+// GetMetadata returns the metadata map for route
+func (r *Route) GetMetadata() map[any]any {
+	return r.metadata
+}
+
+// MetadataContains returns whether or not the key is present in the metadata map
+func (r *Route) MetadataContains(key any) bool {
+	_, ok := r.metadata[key]
+	return ok
+}
+
+// GetMetadataValue returns the value of a specific key in the metadata map. If the key is not present in the map mux.ErrMetadataKeyNotFound is returned
+func (r *Route) GetMetadataValue(key any) (any, error) {
+	value, ok := r.metadata[key]
+	if !ok {
+		return nil, ErrMetadataKeyNotFound
+	}
+
+	return value, nil
+}
+
+// GetMetadataValueOr returns the value of a specific key in the metadata map. If the key is not present in the metadata the fallback value is returned
+func (r *Route) GetMetadataValueOr(key any, fallbackValue any) any {
+	value, ok := r.metadata[key]
+	if !ok {
+		return fallbackValue
+	}
+
+	return value
+}
+
 // Handler --------------------------------------------------------------------
 
 // Handler sets a handler for the route.
diff --git a/route_test.go b/route_test.go
index 5aa35d11..283c3ad5 100644
--- a/route_test.go
+++ b/route_test.go
@@ -1,7 +1,9 @@
 package mux
 
 import (
+	"errors"
 	"net/http"
+	"reflect"
 	"regexp"
 	"sync"
 	"testing"
@@ -64,3 +66,89 @@ func testNewRouter(_ testing.TB, handler http.Handler) {
 	r.Queries("orgID", "{orgID:[0-9]*?}")
 	r.Host("{subdomain}.domain.com")
 }
+
+func TestRouteMetadata(t *testing.T) {
+	router := NewRouter()
+	rw := NewRecorder()
+
+	expectedMap := make(map[any]any)
+	expectedMap["key"] = "value"
+
+	router.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		route := CurrentRoute(r)
+		metadata := route.GetMetadata()
+
+		if !reflect.DeepEqual(metadata, expectedMap) {
+			println(metadata)
+			t.Fatalf("Expected map does not equal the metadata map")
+		}
+
+	}).Metadata("key", "value")
+
+	router.HandleFunc("/single-value", func(w http.ResponseWriter, r *http.Request) {
+		route := CurrentRoute(r)
+		value, err := route.GetMetadataValue("key")
+		if err != nil {
+			t.Fatalf("Expected metadata value to be present, but gave error: %s", err)
+		}
+
+		stringValue, ok := value.(string)
+		if !ok {
+			t.Fatalf("Expected metadata value to be string, but was: %s", reflect.TypeOf(value))
+		}
+
+		if stringValue != "value" {
+			t.Fatalf("Expected metadata value to be '%s', but got '%s'", "value", stringValue)
+		}
+
+		_, err = route.GetMetadataValue("key2")
+		if err == nil {
+			t.Fatalf("Expected metadata key not to be present and error, but error was nil")
+		}
+
+		if !errors.Is(err, ErrMetadataKeyNotFound) {
+			t.Fatalf("Expected error to be ErrMetadataKeyNotFound but got: %s", err)
+		}
+
+	}).Metadata("key", "value")
+
+	router.HandleFunc("/single-value-fallback", func(w http.ResponseWriter, r *http.Request) {
+		route := CurrentRoute(r)
+		value := route.GetMetadataValueOr("key", "value-fallback")
+
+		stringValue, ok := value.(string)
+		if !ok {
+			t.Fatalf("Expected metadata value to be string, but was: %s", reflect.TypeOf(value))
+		}
+
+		if stringValue != "value" {
+			t.Fatalf("Expected metadata value to be '%s', but got '%s'", "value", stringValue)
+		}
+
+		fallbackValue := route.GetMetadataValueOr("key2", "value2")
+		fallbackStringValue, ok := fallbackValue.(string)
+		if !ok {
+			t.Fatalf("Expected metadata value to be string, but was: %s", reflect.TypeOf(value))
+		}
+
+		if fallbackStringValue != "value2" {
+			t.Fatalf("Expected metadata value to be '%s', but got '%s'", "value2", fallbackStringValue)
+		}
+
+	}).Metadata("key", "value")
+
+	t.Run("get metadata map", func(t *testing.T) {
+		req := newRequest("GET", "/")
+		router.ServeHTTP(rw, req)
+	})
+
+	t.Run("get metadata value", func(t *testing.T) {
+		req := newRequest("GET", "/single-value")
+		router.ServeHTTP(rw, req)
+	})
+
+	t.Run("get metadata value or fallback", func(t *testing.T) {
+		req := newRequest("GET", "/single-value-fallback")
+		router.ServeHTTP(rw, req)
+	})
+}