如何阅读#shadow-root（用户代理）下的文本

Question

I am using Selenium (Python) for automating a web page. I am trying to get text from an input field that is under #shadow-root (user-agent). Xpath I used:

driver.find_element_by_xpath("**//*/p-calendar/span/input**").text

is not returning anything. Attached the screenshot of my DOM element. Requirement: To get text from the shadow root : 01:01

Answer 1

You can use driver.execute_script to inject JavaScript code that returns the ShadowRoot then use find_element to get the children element of the shadow root you are looking for.

input_shadow = driver.execute_script('''return document.querySelector("$1").shadowRoot''')
div_text = inputShadow.find_element_by_tag_name("div").text

$1 - Your element's identifier or selector .

If you are keen to using xpath to find elements

input_shadow = driver.execute_script('''return $x(\"//*/p-calendar/span/input\")[0]''')
div_text = inputShadow.find_element_by_tag_name("div").text

Answer 2

As per @hayatoito 's (creator of Shadow DOM) comment :

The original motivation of introducing a closed shadow tree is "Never allow an access to a node in a closed shadow tree, via any APIs, from outside" , AFAIK. Like that we can not access a node in the internal hidden shadow tree which is used in <video> element, in Blink.

In fact, I designed a closed shadow tree in such a way. If there is a way to access a node in a closed shadow tree, it should be considered as a bug of the spec.

I think it's totally okay to have an API to allow an access in the layer of Chrome apps or extensions. However, for a normal web app, I think the current agreement is "Never allow it" .

If we allowed it, that means we do not need a closed shadow tree. Just having an open shadow tree is enough, I think.

Furhter @Supersharp in his comment below his own answer within the discussion How to get element in user-agent shadow root with JavaScript? mentions:

#shadow-root (user-agent) are browser vendors native implementation so they are not documented and will never be accessible. Only open Shadow DOM are, as per the specs

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WebDriver perspective

Recently, @AutomatedTester [David Burns, Chief Bacon Officer, Mozilla Corporation] initiated a discussion on WebDriver - Testability of web components

• Requests
• Proposals
• Issue Tracker

Currently Selenium Team is open for accepting pull requests for the same.

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Reference

You can find a couple of relevant detailed discussions in:

• Need help to click on the element under the shadow Root (closed) type

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Outro

Here you can find a relevant discussion on How to automate shadow DOM elements using selenium?