Merge pull request #7 from louieliu97/ll-add-path-template

Add the ability to store and retrieve the path template

Author: shellfu

route.go

@@ -1,6 +1,7 @@
 package muxer
 
 import (
+	"errors"
 	"net/http"
 	"regexp"
 )
@@ -11,10 +12,11 @@ It contains the regular expression that matches the request path, the HTTP metho
 the handler to be executed for that request, and the parameter names extracted from the path.
 */
 type Route struct {
-	path    *regexp.Regexp
-	method  string
-	handler http.Handler
-	params  []string
+	path     *regexp.Regexp
+	method   string
+	handler  http.Handler
+	params   []string
+	template string
 }
 
 func (r *Route) match(path string) map[string]string {
@@ -30,3 +32,16 @@ func (r *Route) match(path string) map[string]string {
 
 	return params
 }
+
+// PathTemplate retrieves the path template of the current route
+func (r *Route) PathTemplate() (string, error) {
+	if r == nil {
+		return "", errors.New("route is nil, no template")
+	}
+
+	if r.template == "" {
+		return r.template, errors.New("template is empty")
+	}
+
+	return r.template, nil
+}

router.go

@@ -12,6 +12,8 @@ type contextKey string
 const (
 	// ParamsKey is the key used to store the extracted parameters in the request context.
 	ParamsKey contextKey = "params"
+	// RouteContextKey is the key used to store the matched route in the request context
+	RouteContextKey contextKey = "matched_route"
 )
 
 /*
@@ -131,19 +133,20 @@ func (r *Router) HandleRoute(method, path string, handler http.HandlerFunc) {
 	// Parse path to extract parameter names
 	paramNames := make([]string, 0)
 	re := regexp.MustCompile(`:([\w-]+)`)
-	path = re.ReplaceAllStringFunc(path, func(m string) string {
+	pathRegex := re.ReplaceAllStringFunc(path, func(m string) string {
 		paramName := m[1:]
 		paramNames = append(paramNames, paramName)
 		return `([-\w.]+)`
 	})
 
-	exactPath := regexp.MustCompile("^" + path + "$")
+	exactPath := regexp.MustCompile("^" + pathRegex + "$")
 
 	r.routes = append(r.routes, Route{
-		method:  method,
-		path:    exactPath,
-		handler: handler,
-		params:  paramNames,
+		method:   method,
+		path:     exactPath,
+		handler:  handler,
+		params:   paramNames,
+		template: path,
 	})
 }
 
@@ -208,6 +211,7 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 
 		ctx := req.Context()
 		ctx = context.WithValue(ctx, ParamsKey, params)
+		ctx = context.WithValue(ctx, RouteContextKey, &route)
 
 		handler := route.handler
 		for i := len(r.middleware) - 1; i >= 0; i-- {
@@ -256,3 +260,14 @@ the given order before executing the main handler.
 func (r *Router) Use(middleware ...func(http.Handler) http.Handler) {
 	r.middleware = append(r.middleware, middleware...)
 }
+
+// CurrentRoute returns the matched route for the current request, if any.
+// This only works when called inside the handler of the matched route
+// because the matched route is stored inside the request's context,
+// which is wiped after the handler returns.
+func CurrentRoute(r *http.Request) *Route {
+	if rv := r.Context().Value(RouteContextKey); rv != nil {
+		return rv.(*Route)
+	}
+	return nil
+}

router_test.go

@@ -2,6 +2,7 @@ package muxer
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -519,3 +520,102 @@ func TestEnableCORSOption(t *testing.T) {
 		})
 	}
 }
+
+func TestPathTemplate(t *testing.T) {
+	tests := []struct {
+		name           string
+		route          *Route
+		expectedOutput string
+		expectedError  error
+	}{
+		{
+			name:           "Error with nil Route",
+			route:          nil,
+			expectedOutput: "",
+			expectedError:  errors.New("route is nil, no template"),
+		},
+		{
+			name:           "Error with empty template",
+			route:          &Route{template: ""},
+			expectedOutput: "",
+			expectedError:  errors.New("template is empty"),
+		},
+		{
+			name:           "Valid Route with Template and path param",
+			route:          &Route{template: "/users/:id"},
+			expectedOutput: "/users/:id",
+			expectedError:  nil,
+		},
+		{
+			name:           "Valid Route with simple Template",
+			route:          &Route{template: "/metrics"},
+			expectedOutput: "/metrics",
+			expectedError:  nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			output, err := tt.route.PathTemplate()
+
+			if tt.expectedOutput != output {
+				t.Errorf("expected output %v, got %v", tt.expectedOutput, output)
+			}
+			if tt.expectedError != nil {
+				if tt.expectedError.Error() != err.Error() {
+					t.Errorf("expected error %v, got %v", tt.expectedError, err)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("expected error to be nil, got %v", err)
+				}
+			}
+		})
+	}
+}
+
+func TestCurrentRoute(t *testing.T) {
+	route := &Route{template: "/users/:id"}
+
+	tests := []struct {
+		name          string
+		contextKey    interface{}
+		contextValue  interface{}
+		expectedRoute *Route
+	}{
+		{
+			name:          "Route in context",
+			contextKey:    RouteContextKey,
+			contextValue:  route,
+			expectedRoute: route,
+		},
+		{
+			name:          "No route in context",
+			contextKey:    "some_other_key",
+			contextValue:  "some_value",
+			expectedRoute: nil,
+		},
+		{
+			name:          "Empty context",
+			contextKey:    nil,
+			contextValue:  nil,
+			expectedRoute: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req, _ := http.NewRequest(http.MethodGet, "/users/123", nil)
+
+			if tt.contextKey != nil {
+				req = req.WithContext(context.WithValue(req.Context(), tt.contextKey, tt.contextValue))
+			}
+
+			result := CurrentRoute(req)
+
+			if tt.expectedRoute != result {
+				t.Errorf("expected route %v got %v", tt.expectedRoute, result)
+			}
+		})
+	}
+}