Add context.FindClosest(n) to find closest paths - useful for 404 pages to suggest valid pages

Former-commit-id: 90ff7c9da5369df5bd99fbbecf9955a8c555fea5

_examples/README.md

@@ -128,6 +128,7 @@ Navigate through examples for a better understanding.
 - [Basic](routing/basic/main.go)
 - [Controllers](mvc)
 - [Custom HTTP Errors](routing/http-errors/main.go)
+- [Not Found - Suggest Closest Paths](routing/not-found-suggests/main.go) **NEW**
 - [Dynamic Path](routing/dynamic-path/main.go)
     * [root level wildcard path](routing/dynamic-path/root-wildcard/main.go)
 - [Write your own custom parameter types](routing/macros/main.go)

_examples/i18n/main.go

@@ -54,7 +54,7 @@ func newApp() *iris.Application {
 
 		// Note that,
 		// Iris automatically adds a "tr" global template function as well,
-		// the only differene is the way you call it inside your templates and
+		// the only difference is the way you call it inside your templates and
 		// that it accepts a language code as its first argument: {{ tr "el-GR" "hi" "iris"}}
 	})
 	//
@@ -65,10 +65,18 @@ func newApp() *iris.Application {
 func main() {
 	app := newApp()
 
-	// go to http://localhost:8080/el-gr/some-path (by path prefix)
-	// or http://el.mydomain.com8080/some-path (by subdomain - test locally with the hosts file)
-	// or http://localhost:8080/zh-CN/templates (by path prefix with uppercase)
-	// or http://localhost:8080/some-path?lang=el-GR (by url parameter)
+	// go to http://localhost:8080/el-gr/some-path
+	// ^ (by path prefix)
+	//
+	// or http://el.mydomain.com8080/some-path
+	// ^ (by subdomain - test locally with the hosts file)
+	//
+	// or http://localhost:8080/zh-CN/templates
+	// ^ (by path prefix with uppercase)
+	//
+	// or http://localhost:8080/some-path?lang=el-GR
+	// ^ (by url parameter)
+	//
 	// or http://localhost:8080 (default is en-US)
 	// or http://localhost:8080/?lang=zh-CN
 	//
@@ -77,6 +85,5 @@ func main() {
 	// or http://localhost:8080/other?lang=en-US
 	//
 	// or use cookies to set the language.
-	//
 	app.Run(iris.Addr(":8080"), iris.WithSitemap("http://localhost:8080"))
 }

_examples/routing/not-found-suggests/main.go

@@ -0,0 +1,37 @@
+package main
+
+import "github.com/kataras/iris/v12"
+
+func main() {
+	app := iris.New()
+	app.OnErrorCode(iris.StatusNotFound, notFound)
+
+	// [register some routes...]
+	app.Get("/home", handler)
+	app.Get("/news", handler)
+	app.Get("/news/politics", handler)
+	app.Get("/user/profile", handler)
+	app.Get("/user", handler)
+	app.Get("/newspaper", handler)
+	app.Get("/user/{id}", handler)
+
+	app.Run(iris.Addr(":8080"))
+}
+
+func notFound(ctx iris.Context) {
+	suggestPaths := ctx.FindClosest(3)
+	if len(suggestPaths) == 0 {
+		ctx.WriteString("404 not found")
+		return
+	}
+
+	ctx.HTML("Did you mean?<ul>")
+	for _, s := range suggestPaths {
+		ctx.HTML(`<li><a href="%s">%s</a></li>`, s, s)
+	}
+	ctx.HTML("</ul>")
+}
+
+func handler(ctx iris.Context) {
+	ctx.Writef("Path: %s", ctx.Path())
+}