Router a good

tree.go

@@ -0,0 +1,67 @@
+package router
+
+import (
+	"errors"
+	"net/http"
+	"path"
+	"strings"
+)
+
+var Wildcard = "{}"
+var WildcardHeader = "__wildcard_value__"
+
+type tree struct {
+	next    map[string]*tree
+	handler http.HandlerFunc
+}
+
+func newTree() *tree {
+	return &tree{
+		next:    make(map[string]*tree),
+		handler: nil,
+	}
+}
+
+func (t *tree) Lookup(path string) http.HandlerFunc {
+	if path == "/" || path == "" {
+		return t.handler
+	}
+	key, following := nextPathSegment(path)
+	if n, ok := t.next[key]; ok {
+		return n.Lookup(following)
+	} else if n, ok := t.next[Wildcard]; ok {
+		foo := n.Lookup(following)
+		if foo != nil {
+			return func(w http.ResponseWriter, r *http.Request) {
+				r.Header.Add(WildcardHeader, key)
+				foo(w, r)
+			}
+		}
+	}
+	return nil
+}
+
+func (t *tree) Insert(path string, foo http.HandlerFunc) error {
+	if path == "/" {
+		if t.handler != nil {
+			return errors.New("occupied path")
+		}
+		t.handler = foo
+		return nil
+	}
+	key, following := nextPathSegment(path)
+	_, ok := t.next[key]
+	if !ok {
+		t.next[key] = newTree()
+	}
+	return t.next[key].Insert(following, foo)
+}
+
+func nextPathSegment(p string) (string, string) {
+	p = path.Clean("/" + p)
+	i := strings.Index(p[1:], "/") + 1
+	if i <= 0 {
+		return p[1:], "/"
+	}
+	return p[1:i], p[i:]
+}