User control (#26)

* UserControl draft

* Do not reference UserControl

* UserControl complete

* Go 1.18.3

* An ability to choose Flutter web renderer

* page.set_clipboard(), page.show_snack_bar()

Author: FeodorFitsner

.appveyor.yml

@@ -9,7 +9,7 @@ skip_commits:
     - "*.md"
 
 environment:
-  GO_VERSION: 1.18.1
+  GO_VERSION: 1.18.3
   GO_TAGS: --tags release
   python_version: 3.10
   GITHUB_TOKEN:

client/web/index.html

@@ -19,6 +19,8 @@
   <title>Flet</title>
   <link rel="manifest" href="manifest.json">
 
+  <!-- flutterWebRenderer -->
+
   <script>
     // The value below is injected by flutter build, do not touch.
     var serviceWorkerVersion = null;

sdk/python/flet/__init__.py

@@ -40,4 +40,5 @@
 from flet.text_button import TextButton
 from flet.textfield import TextField
 from flet.theme import Theme
+from flet.user_control import UserControl
 from flet.vertical_divider import VerticalDivider

sdk/python/flet/clipboard.py

@@ -36,6 +36,9 @@ def __init__(
     def _get_control_name(self):
         return "clipboard"
 
+    def _is_isolated(self):
+        return True
+
     # value
     @property
     def value(self):

sdk/python/flet/control.py

@@ -86,8 +86,14 @@ def __init__(
         if ref:
             ref.current = self
 
-    def _assign(self, variable):
-        variable = self
+    def _is_isolated(self):
+        return False
+
+    def did_mount(self):
+        pass
+
+    def will_unmount(self):
+        pass
 
     def _get_children(self):
         return []
@@ -306,7 +312,8 @@ def build_update_commands(self, index, added_controls, commands):
                 # unchanged control
                 for h in previous_ints[a1:a2]:
                     ctrl = hashes[h]
-                    ctrl.build_update_commands(index, added_controls, commands)
+                    if not ctrl._is_isolated():
+                        ctrl.build_update_commands(index, added_controls, commands)
                     n += 1
             elif tag == "replace":
                 ids = []
@@ -358,6 +365,7 @@ def _remove_control_recursively(self, index, control):
             self._remove_control_recursively(index, child)
 
         if control.__uid in index:
+            control.will_unmount()
             del index[control.__uid]
 
     # private methods

sdk/python/flet/flet.py

@@ -35,16 +35,24 @@
     FLET_APP,
 ]
 
+WebRenderer = Literal[None, "auto", "html", "canvaskit"]
+
 
 def page(
-    name="", port=0, permissions=None, view: AppViewer = WEB_BROWSER, assets_dir=None
+    name="",
+    port=0,
+    permissions=None,
+    view: AppViewer = WEB_BROWSER,
+    assets_dir=None,
+    web_renderer=None,
 ):
     conn = _connect_internal(
         page_name=name,
         port=port,
         is_app=False,
         permissions=permissions,
         assets_dir=assets_dir,
+        web_renderer=web_renderer,
     )
     print("Page URL:", conn.page_url)
     page = Page(conn, constants.ZERO_SESSION)
@@ -63,6 +71,7 @@ def app(
     permissions=None,
     view: AppViewer = FLET_APP,
     assets_dir=None,
+    web_renderer=None,
 ):
 
     if target == None:
@@ -75,6 +84,7 @@ def app(
         permissions=permissions,
         session_handler=target,
         assets_dir=assets_dir,
+        web_renderer=web_renderer,
     )
     print("App URL:", conn.page_url)
 
@@ -129,6 +139,7 @@ def _connect_internal(
     permissions=None,
     session_handler=None,
     assets_dir=None,
+    web_renderer=None,
 ):
     if share and server == None:
         server = constants.HOSTED_SERVICE_URL
@@ -141,7 +152,7 @@ def _connect_internal(
         # page with a custom port starts detached process
         attached = False if not is_app and port != 0 else True
 
-        port = _start_flet_server(port, attached, assets_dir)
+        port = _start_flet_server(port, attached, assets_dir, web_renderer)
         server = f"http://localhost:{port}"
 
     connected = threading.Event()
@@ -209,7 +220,7 @@ def _on_ws_failed_connect():
     return conn
 
 
-def _start_flet_server(port, attached, assets_dir):
+def _start_flet_server(port, attached, assets_dir, web_renderer):
 
     if port == 0:
         port = _get_free_tcp_port()
@@ -243,6 +254,10 @@ def _start_flet_server(port, attached, assets_dir):
         logging.info(f"Assets path configured: {assets_dir}")
         fletd_env["FLET_STATIC_ROOT_DIR"] = assets_dir
 
+    if web_renderer not in [None, "", "auto"]:
+        logging.info(f"Web renderer configured: {web_renderer}")
+        fletd_env["FLET_WEB_RENDERER"] = web_renderer
+
     args = [fletd_path, "--port", str(port)]
 
     creationflags = 0

sdk/python/flet/page.py

@@ -117,6 +117,10 @@ def __update(self, *controls):
 
                     # add to index
                     self._index[id] = added_controls[n]
+
+                    # call Control.did_mount
+                    added_controls[n].did_mount()
+
                     n += 1
 
     def add(self, *controls):
@@ -219,6 +223,16 @@ def _send_command(self, name: str, values: List[str]):
             Command(0, name, values, None, None),
         )
 
+    @beartype
+    def set_clipboard(self, value: str):
+        self.__offstage.clipboard.value = value
+        self.__offstage.clipboard.update()
+
+    @beartype
+    def show_snack_bar(self, snack_bar: SnackBar):
+        self.__offstage.snack_bar = snack_bar
+        self.__offstage.update()
+
     # url
     @property
     def url(self):
@@ -341,16 +355,6 @@ def fonts(self, value: Optional[Dict[str, str]]):
         self.__fonts = value
         self._set_attr_json("fonts", value)
 
-    # clipboard
-    @property
-    def clipboard(self):
-        return self.__offstage.clipboard.value
-
-    @clipboard.setter
-    @beartype
-    def clipboard(self, value: Optional[str]):
-        self.__offstage.clipboard.value = value
-
     # splash
     @property
     def splash(self):

sdk/python/flet/user_control.py

@@ -0,0 +1,26 @@
+from typing import List
+
+from flet.control import Control
+from flet.stack import Stack
+
+
+class UserControl(Stack):
+    def __init__(self):
+        super().__init__()
+        content = self.build()
+        if isinstance(content, Control):
+            self.controls = [content]
+        elif isinstance(content, List) and all(
+            isinstance(control, Control) for control in content
+        ):
+            self.controls = content
+        else:
+            raise Exception(
+                f"{self.__class__.__name__}.build() method must be implemented and returning either Control or List[Control]."
+            )
+
+    def build(self):
+        pass
+
+    def _is_isolated(self):
+        return True

server/config/config.go

@@ -71,6 +71,7 @@ const (
 
 	// development
 	staticRootDir = "STATIC_ROOT_DIR"
+	webRenderer   = "WEB_RENDERER"
 )
 
 func init() {
@@ -278,3 +279,7 @@ func MasterSecretKey() string {
 func StaticRootDir() string {
 	return viper.GetString(staticRootDir)
 }
+
+func WebRenderer() string {
+	return viper.GetString(webRenderer)
+}

server/server/server.go

@@ -105,10 +105,19 @@ func Start(ctx context.Context, wg *sync.WaitGroup, serverPort int) {
 			index, _ := assetsFS.Open(siteDefaultDocument)
 			indexData, _ := ioutil.ReadAll(index)
 
-			c.Data(http.StatusOK, "text/html",
-				bytes.Replace(indexData,
-					[]byte("<base href=\"/\">"),
-					[]byte("<base href=\""+urlPath+"\">"), 1))
+			// base path
+			indexData = bytes.Replace(indexData,
+				[]byte("<base href=\"/\">"),
+				[]byte("<base href=\""+urlPath+"\">"), 1)
+
+			// web renderer
+			if config.WebRenderer() != "" {
+				indexData = bytes.Replace(indexData,
+					[]byte("<!-- flutterWebRenderer -->"),
+					[]byte("<script>window.flutterWebRenderer=\""+config.WebRenderer()+"\";</script>"), 1)
+			}
+
+			c.Data(http.StatusOK, "text/html", indexData)
 		} else {
 			// API not found
 			c.JSON(http.StatusNotFound, gin.H{