WIP: http mux based on match by ben hoyt

go.mod

@@ -1,3 +1,3 @@
 module github.com/jchenry/x
 
-go 1.13
+go 1.18

net/http/mux.go

@@ -0,0 +1,95 @@
+package http
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+)
+
+type ServeMux struct {
+	routes []route
+}
+
+func (mux *ServeMux) Handle(pattern string, handler http.Handler, pathParams ...any) {
+	mux.routes = append(mux.routes, newRoute(pattern, handler, pathParams...))
+}
+
+func (mux *ServeMux) HandleFunc(pattern string, handler func(http.ResponseWriter, *http.Request), pathParams ...any) {
+	mux.routes = append(mux.routes, newRoute(pattern, http.HandlerFunc(handler), pathParams...))
+}
+
+func (mux *ServeMux) Handler(r *http.Request) (h http.Handler, pattern string) {
+	for _, rte := range mux.routes {
+		switch {
+		case rte.matcher(r):
+			return rte.handler, rte.pattern
+		}
+	}
+	return http.HandlerFunc(http.NotFound), ""
+}
+
+func (mux *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.RequestURI == "*" {
+		if r.ProtoAtLeast(1, 1) {
+			w.Header().Set("Connection", "close")
+		}
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+	h, _ := mux.Handler(r)
+	h.ServeHTTP(w, r)
+}
+
+type route struct {
+	pattern string
+	matcher func(r *http.Request) bool
+	handler http.HandlerFunc
+}
+
+func newRoute(pattern string, handler http.Handler, vars ...interface{}) route {
+	return route{
+		pattern,
+		func(r *http.Request) bool {
+			return match(r.URL.Path, pattern, vars...)
+		},
+		handler.ServeHTTP,
+	}
+}
+
+// match reports whether path matches the given pattern, which is a
+// path with '+' wildcards wherever you want to use a parameter. Path
+// parameters are assigned to the pointers in vars (len(vars) must be
+// the number of wildcards), which must be of type *string or *int.
+func match(path, pattern string, vars ...interface{}) bool {
+	for ; pattern != "" && path != ""; pattern = pattern[1:] {
+		switch pattern[0] {
+		case '+':
+			// '+' matches till next slash in path
+			slash := strings.IndexByte(path, '/')
+			if slash < 0 {
+				slash = len(path)
+			}
+			segment := path[:slash]
+			path = path[slash:]
+			switch p := vars[0].(type) {
+			case *string:
+				*p = segment
+			case *int:
+				n, err := strconv.Atoi(segment)
+				if err != nil || n < 0 {
+					return false
+				}
+				*p = n
+			default:
+				panic("vars must be *string or *int")
+			}
+			vars = vars[1:]
+		case path[0]:
+			// non-'+' pattern byte must match path byte
+			path = path[1:]
+		default:
+			return false
+		}
+	}
+	return path == "" && pattern == ""
+}