editor: support editing from other shared pages

editor/resources/index.html

@@ -41,7 +41,8 @@
           }
         })
 
-      const initialConfig = {
+      // can be changed if specified by '?from=<name>'
+      let initialConfig = {
         "html_title": "cloudflare.com | 500: Internal server error",
         "title": "Internal server error",
         "error_code": 500,
@@ -139,6 +140,30 @@
         },
       };
 
+      const urlParams = new URLSearchParams(window.location.search);
+      const defaultPresetName = urlParams.get('from');
+      if (defaultPresetName && defaultPresetName.indexOf('/') < 0) {
+        fetch(`../s/${defaultPresetName}`, {
+          headers: {
+            'Accept': 'application/json'
+          },
+        })
+        .then(response => {
+          if (!response.ok) {
+            throw new Error('failed to get preset');
+          }
+          return response.json();
+        })
+        .then(result => {
+          if (result.status != 'ok') {
+            return
+          }
+          console.log(result.parameters)
+          initialConfig = result.parameters
+          loadConfig(initialConfig);
+        })
+      }
+
       /* Utilities */
       function $(id) { return document.getElementById(id); }
 

editor/server/share.py

@@ -57,8 +57,16 @@ def create():
 
 @bp.get('/<name>')
 def get(name: str):
+    accept = request.headers.get('Accept', '')
+    is_json = 'application/json' in accept
+
     item = db.session.query(models.Item).filter_by(name=name).first()
     if not item:
+        if is_json:
+            return jsonify({
+                'status': 'not-found'
+            })
+        else:
             return abort(404)
     params = item.params
     params = {
@@ -73,4 +81,11 @@ def get(name: str):
         'text': 'CF Error Page Editor',
         'link': f'https://virt.moe/cloudflare-error-page/editor/?from={name}',
     }
+    
+    if is_json:
+        return jsonify({
+            'status': 'ok',
+            'parameters': params,
+        })
+    else:
         return render_cf_error_page(params=params, allow_html=False, use_cdn=True), 200