Add suport for DoH over HTTP/3

vendor/github.com/go-task/slim-sprig/url.go

@@ -0,0 +1,66 @@
+package sprig
+
+import (
+	"fmt"
+	"net/url"
+	"reflect"
+)
+
+func dictGetOrEmpty(dict map[string]interface{}, key string) string {
+	value, ok := dict[key]
+	if !ok {
+		return ""
+	}
+	tp := reflect.TypeOf(value).Kind()
+	if tp != reflect.String {
+		panic(fmt.Sprintf("unable to parse %s key, must be of type string, but %s found", key, tp.String()))
+	}
+	return reflect.ValueOf(value).String()
+}
+
+// parses given URL to return dict object
+func urlParse(v string) map[string]interface{} {
+	dict := map[string]interface{}{}
+	parsedURL, err := url.Parse(v)
+	if err != nil {
+		panic(fmt.Sprintf("unable to parse url: %s", err))
+	}
+	dict["scheme"] = parsedURL.Scheme
+	dict["host"] = parsedURL.Host
+	dict["hostname"] = parsedURL.Hostname()
+	dict["path"] = parsedURL.Path
+	dict["query"] = parsedURL.RawQuery
+	dict["opaque"] = parsedURL.Opaque
+	dict["fragment"] = parsedURL.Fragment
+	if parsedURL.User != nil {
+		dict["userinfo"] = parsedURL.User.String()
+	} else {
+		dict["userinfo"] = ""
+	}
+
+	return dict
+}
+
+// join given dict to URL string
+func urlJoin(d map[string]interface{}) string {
+	resURL := url.URL{
+		Scheme:   dictGetOrEmpty(d, "scheme"),
+		Host:     dictGetOrEmpty(d, "host"),
+		Path:     dictGetOrEmpty(d, "path"),
+		RawQuery: dictGetOrEmpty(d, "query"),
+		Opaque:   dictGetOrEmpty(d, "opaque"),
+		Fragment: dictGetOrEmpty(d, "fragment"),
+	}
+	userinfo := dictGetOrEmpty(d, "userinfo")
+	var user *url.Userinfo
+	if userinfo != "" {
+		tempURL, err := url.Parse(fmt.Sprintf("proto://%s@host", userinfo))
+		if err != nil {
+			panic(fmt.Sprintf("unable to parse userinfo in dict: %s", err))
+		}
+		user = tempURL.User
+	}
+
+	resURL.User = user
+	return resURL.String()
+}