create the new FileServer and HandleDir, deprecate the rest APIBuilder/Party static methods and more

relative: https://github.com/kataras/iris/issues/1283 and removing pongo2 from vendor: https://github.com/kataras/iris/issues/1284

Former-commit-id: 3ec57b349f99faca2b8e36d9f7252db0b6ea080d

context/route.go

@@ -1,6 +1,13 @@
 package context
 
-import "github.com/kataras/iris/macro"
+import (
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/kataras/iris/macro"
+)
 
 // RouteReadOnly allows decoupled access to the current route
 // inside the context.
@@ -42,4 +49,59 @@ type RouteReadOnly interface {
 
 	// MainHandlerName returns the first registered handler for the route.
 	MainHandlerName() string
+
+	// StaticSites if not empty, refers to the system (or virtual if embedded) directory
+	// and sub directories that this "GET" route was registered to serve files and folders
+	// that contain index.html (a site). The index handler may registered by other
+	// route, manually or automatic by the framework,
+	// get the route by `Application#GetRouteByPath(staticSite.RequestPath)`.
+	StaticSites() []StaticSite
+}
+
+// StaticSite is a structure which is used as field on the `Route`
+// and route registration on the `APIBuilder#HandleDir`.
+// See `GetStaticSites` and `APIBuilder#HandleDir`.
+type StaticSite struct {
+	Dir         string `json:"dir"`
+	RequestPath string `json:"requestPath"`
+}
+
+// GetStaticSites search for a relative filename of "indexName" in "rootDir" and all its subdirectories
+// and returns a list of structures which contains the directory found an "indexName" and the request path
+// that a route should be registered to handle this "indexName".
+// The request path is given by the directory which an index exists on.
+func GetStaticSites(rootDir, rootRequestPath, indexName string) (sites []StaticSite) {
+	f, err := os.Open(rootDir)
+	if err != nil {
+		return nil
+	}
+
+	list, err := f.Readdir(-1)
+	f.Close()
+	if err != nil {
+		return nil
+	}
+
+	if len(list) == 0 {
+		return nil
+	}
+
+	for _, l := range list {
+		dir := filepath.Join(rootDir, l.Name())
+
+		if l.IsDir() {
+			sites = append(sites, GetStaticSites(dir, path.Join(rootRequestPath, l.Name()), indexName)...)
+			continue
+		}
+
+		if l.Name() == strings.TrimPrefix(indexName, "/") {
+			sites = append(sites, StaticSite{
+				Dir:         filepath.FromSlash(rootDir),
+				RequestPath: rootRequestPath,
+			})
+			continue
+		}
+	}
+
+	return
 }