From f1532f9ea0bee961394ab0d609f0e87860d42f04 Mon Sep 17 00:00:00 2001
From: Richard Carson Derr <cakub6@gmx.com>
Date: Wed, 2 Oct 2024 22:48:08 -0400
Subject: [PATCH] feat(issue-295): register trailing slash and non-trailing
 slash endpoints to avoid redirects

---
 rest/mux/mux.go      | 30 ++++++++++++++++++++++++++++++
 rest/mux/mux_test.go |  6 ++----
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/rest/mux/mux.go b/rest/mux/mux.go
index 37ebe98..cba5039 100644
--- a/rest/mux/mux.go
+++ b/rest/mux/mux.go
@@ -9,7 +9,9 @@ package mux
 import (
 	"fmt"
 	"net/http"
+	"path"
 	"slices"
+	"strings"
 	"sync"
 )
 
@@ -72,6 +74,34 @@ func NewHttp(opts ...HttpOption) *Http {
 func (m *Http) Handle(method Method, pattern string, h http.Handler) {
 	m.pathMethods[pattern] = append(m.pathMethods[pattern], method)
 	m.mux.Handle(fmt.Sprintf("%s %s", method, pattern), h)
+
+	// {$} is a special case where we only want to exact match the path pattern.
+	if strings.HasSuffix(pattern, "{$}") {
+		return
+	}
+
+	if strings.HasSuffix(pattern, "/") {
+		withoutTrailingSlash := pattern[:len(pattern)-1]
+		if len(withoutTrailingSlash) == 0 {
+			return
+		}
+
+		m.pathMethods[withoutTrailingSlash] = append(m.pathMethods[withoutTrailingSlash], method)
+		m.mux.Handle(fmt.Sprintf("%s %s", method, withoutTrailingSlash), h)
+		return
+	}
+
+	// if the end of the path contains the "..." wildcard segment
+	// then we can't add a "/" to it since "..." should not be followed
+	// by a "/", per the http.ServeMux docs.
+	base := path.Base(pattern)
+	if strings.Contains(base, "...") {
+		return
+	}
+
+	withTrailingSlash := pattern + "/"
+	m.pathMethods[withTrailingSlash] = append(m.pathMethods[withTrailingSlash], method)
+	m.mux.Handle(fmt.Sprintf("%s %s", method, withTrailingSlash), h)
 }
 
 // ServeHTTP implements the [http.Handler] interface.
diff --git a/rest/mux/mux_test.go b/rest/mux/mux_test.go
index 7acb43c..a282b2d 100644
--- a/rest/mux/mux_test.go
+++ b/rest/mux/mux_test.go
@@ -7,11 +7,9 @@ package mux
 
 import (
 	"encoding/json"
-	"fmt"
 	"io"
 	"net/http"
 	"net/http/httptest"
-	"path"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -92,7 +90,7 @@ func TestNotFoundHandler(t *testing.T) {
 			w := httptest.NewRecorder()
 			r := httptest.NewRequest(
 				http.MethodGet,
-				fmt.Sprintf("http://%s", path.Join("example.com", testCase.RequestPath)),
+				"http://example.com"+testCase.RequestPath,
 				nil,
 			)
 
@@ -189,7 +187,7 @@ func TestMethodNotAllowedHandler(t *testing.T) {
 			w := httptest.NewRecorder()
 			r := httptest.NewRequest(
 				string(testCase.Method),
-				fmt.Sprintf("http://%s", path.Join("example.com", testCase.RequestPath)),
+				"http://example.com"+testCase.RequestPath,
 				nil,
 			)