page.py 文件源码

def exposeFunction(self, name: str, puppeteerFunction: Callable
                             ) -> None:
        """Execute function on this page."""
        if self._pageBindings[name]:
            raise PageError(f'Failed to add page binding with name {name}: '
                            'window["{name}"] already exists!')
        self._pageBindings[name] = puppeteerFunction

        addPageBinding = '''
function addPageBinding(bindingName) {
  window[bindingName] = async(...args) => {
    const me = window[bindingName];
    let callbacks = me['callbacks'];
    if (!callbacks) {
      callbacks = new Map();
      me['callbacks'] = callbacks;
    }
    const seq = (me['lastSeq'] || 0) + 1;
    me['lastSeq'] = seq;
    const promise = new Promise(fulfill => callbacks.set(seq, fulfill));
    // eslint-disable-next-line no-console
    console.debug('driver:page-binding', JSON.stringify({name: bindingName, seq, args}));
    return promise;
  };
}
        '''  # noqa: E501
        expression = helper.evaluationString(addPageBinding, name)
        await self._client.send('Page.addScriptToEvaluateOnNewDocument',
                                {'source': expression})
        await self._client.send('Runtime.evaluate', {
            'expression': expression,
            'returnByValue': True
        })