feat: add loading hint at page initialization

pywebio/html/index.html

@@ -26,6 +26,12 @@
                 警告：您正在使用旧版本的方式来实现PyWebIO与Web框架整合，此方式在当前版本中已经不被推荐，并在将来可能会被移除。<br/>
                 请访问<a href="https://pywebio.readthedocs.io/zh_CN/latest/guide.html#web" target="_blank" class="alert-link">此处</a>来查看新版本PyWebIO中与Web框架整合更简单的方式。
             </div>
+            <div class="text-center" id="pywebio-loading" style="display: none; position: fixed; top: 40%; left: 0;right: 0;">
+                <div class="spinner-grow text-info" role="status">
+                    <span class="sr-only">Loading...</span>
+                </div>
+            </div>
+
             <div id="pywebio-scope-ROOT"></div>
         </div>
         <div id="end-space"></div>

pywebio/platform/tpl/index.html

@@ -18,6 +18,12 @@
 <div class="pywebio">
     <div class="container no-fix-height" id="output-container">
         <div class="markdown-body" id="markdown-body">
+            <div class="text-center" id="pywebio-loading" style="display: none; position: fixed; top: 40%; left: 0;right: 0;">
+                <div class="spinner-grow text-info" role="status">
+                    <span class="sr-only">Loading...</span>
+                </div>
+            </div>
+
             <div id="pywebio-scope-ROOT">{% raw content %}</div>
         </div>
         <div id="end-space"></div>

webiojs/src/main.ts

@@ -18,7 +18,9 @@ function backend_absaddr(addr: string) {
 // 初始化Handler和Session
 function set_up_session(webio_session: Session, output_container_elem: JQuery, input_container_elem: JQuery) {
     state.CurrentSession = webio_session;
+    $('#pywebio-loading').show();
     webio_session.on_session_create(function () {
+        $('#pywebio-loading').hide();
         $('#favicon32').attr('href', 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAwklEQVQ4T63TvU5CQRCG4WcwMfEuqOgNtQ2Nd4CxV2LHtVhJ0N7AHdjQUBtrrLwLA4ks2Rx+/Qucw3Y78807M7sz4ft5dq6mI7RQX7o/JCNzfdfetkNifRk6k9wLN9jYdxMkyZPQ1faZXYUwB/OCix8V/W4Y4zJDCsBAX7jdM7iQJY+udELu+cTrP2X/xU2+NMPAg3B3UPaVOOmFoQkapQC8Z8AUpyUBs6MAKrZQ+RErf2PlQTrKKK8gpZdpewgOXOcFTTxEjYwMoIkAAAAASUVORK5CYII=');
         $('#favicon16').attr('href', 'data:image/png;base64,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');
     });

webiojs/src/session.ts

@@ -197,8 +197,8 @@ export class HttpSession implements Session {
             dataType: "json",
             headers: {"webio-session-id": this.webio_session_id},
             success: function (data: Command[], textStatus: string, jqXHR: JQuery.jqXHR) {
-                that._on_request_success(data, textStatus, jqXHR);
                 that._on_session_create();
+                that._on_request_success(data, textStatus, jqXHR);
             },
             error: function () {
                 console.error('Http pulling failed');