app.py

from h2o_wave import main, app, Q, ui

@app('/')
async def serve(q: Q):
 # Initialize the page with a single button.
 if not q.client.initialized:
   q.page['form'] = ui.form_card(
     box='1 1 2 1',
     items=[
       ui.button(name='start_recording', label='Start recording')
     ]
   )
   # Load JS polyfills to record on older browsers as well.
   q.page['meta'] = ui.meta_card(
     box='',
     scripts=[
       ui.script('https://cdn.jsdelivr.net/npm/opus-media-recorder@latest/OpusMediaRecorder.umd.js', asynchronous=False),
       ui.script('https://cdn.jsdelivr.net/npm/opus-media-recorder@latest/encoderWorker.umd.js', asynchronous=False),
     ]
   )
   # Load initial JS from file record_utils.js.
   with open('record.js', encoding='utf-8') as f:
     q.page['meta'].script = ui.inline_script(f.read())
   q.client.initialized = True
  
await q.page.save()