Element screenshot when `iframe` is active appears to switch to main window

[roboaks]

Here's the scenario. We are calling the new shootElement method passing a WebElement that corresponds to a scrollable div i n the main window. Support for this usage is now built into our AFT framework and it works fine except if...

1. The AFT clicks a button (or does something) that causes an iframe-based popup to be displayed
2. Does a Selenium switch to that iframe
3. Calls shootElement using the usual parameters

What seems to happen is that ShutterBug uses Selenium to switch back to the main window to execute shootElement. Then when the AFT proceeds, it fails because the popup iframe is no longer active. Is it indeed possible that ShutterBug uses Selenium to switch back to the main window?

What I tried next was to change the ShutterBug config on the fly (our framework supports that) so that shootFrame is called, supplying the iframe WebElement and using the VIEWPORT strategy (since we don't need to scroll the popup). This generates:

__EXCEPTION__:org.openqa.selenium.JavascriptException: javascript error: Cannot read property 'scrollIntoView' of null
  (Session info: chrome=84.0.4147.135)
Build info: version: 'unknown', revision: 'unknown', time: 'unknown'
System info: host: 'GitHub', ip: '172.30.1.67', os.name: 'Windows Server 2016', os.arch: 'amd64', os.version: '10.0', java.version: '1.8.0_241'
Driver info: org.openqa.selenium.chrome.ChromeDriver
Capabilities {acceptInsecureCerts: false, browserName: chrome, browserVersion: 84.0.4147.135, chrome: {chromedriverVersion: 84.0.4147.30 (48b3e868b4cc0..., userDataDir: C:\Users\ITSUser\AppData\Lo...}, goog:chromeOptions: {debuggerAddress: localhost:51855}, javascriptEnabled: true, networkConnectionEnabled: false, pageLoadStrategy: normal, platform: WINDOWS, platformName: WINDOWS, proxy: Proxy(), setWindowRect: true, strictFileInteractability: false, timeouts: {implicit: 0, pageLoad: 300000, script: 30000}, unhandledPromptBehavior: dismiss and notify, webauthn:virtualAuthenticators: true}
Session ID: e1f1da63824ad197ee5bd5b7b405da0c
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) [rt.jar:1.8.0_241]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) [rt.jar:1.8.0_241]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) [rt.jar:1.8.0_241]
	at java.lang.reflect.Constructor.newInstance(Unknown Source) [rt.jar:1.8.0_241]
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.createException(W3CHttpResponseCodec.java:187) [SeleniumFixture-all.jar]
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.decode(W3CHttpResponseCodec.java:122) [SeleniumFixture-all.jar]
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.decode(W3CHttpResponseCodec.java:49) [SeleniumFixture-all.jar]
	at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:158) [SeleniumFixture-all.jar]
	at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:83) [SeleniumFixture-all.jar]
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:552) [SeleniumFixture-all.jar]
	at org.openqa.selenium.remote.RemoteWebDriver.executeScript(RemoteWebDriver.java:489) [SeleniumFixture-all.jar]
	at com.assertthat.selenium_shutterbug.utils.web.Browser.executeJsScript(Browser.java:668) [SeleniumFixture-all.jar]
	at com.assertthat.selenium_shutterbug.utils.web.Browser.scrollToElement(Browser.java:644) [SeleniumFixture-all.jar]
	at com.assertthat.selenium_shutterbug.core.Shutterbug.shootFrame(Shutterbug.java:337) [SeleniumFixture-all.jar]
	at com.assertthat.selenium_shutterbug.core.Shutterbug.shootFrame(Shutterbug.java:301) [SeleniumFixture-all.jar]
	at com.its.itap.fixtures.selenium.helpers.Screenshot._saveScreenshot(Screenshot.java:479) [SeleniumFixture-all.jar]
	at com.its.itap.fixtures.selenium.helpers.Screenshot.saveScreenshot(Screenshot.java:607) [SeleniumFixture-all.jar]
...

I suspect that ShutterBug doesn't like the VIEWPORT strategy for a frame. Since the frame popup is small and will always be in view, I suppose I could just use the ShutterBug shootPage method.

Thoughts?

[glibas]

Hi @roboaks

Thank you for reporting.

• The issue with shootElement is now fixed in v1.2. Shutterbug wont switch to default content after taking element screenshot.

• The issue with frame screenshot you are seeing is due to you are switching to the frame before taking screenshot. Shutterbug needs driver to be switched to default content before taking screenshot, e.g.

driver.switchTo().defaultContent();
Shutterbug.shootFrame(driver, "frameID", CaptureElement.VIEWPORT).save();

I've added related note to README.

Thanks,
Glib

[roboaks]

Thank you so much for the swift response Glib!

We will test things out today and let you know if we have any issues.

[roboaks]

This fix worked perfectly. Furthermore, we took the simplest approach to shooting the popup, which is to simply take a viewport screenshot of the main window (which includes the popup); it worked perfectly.

Thanks again Glib :-)

[glibas]

Hi Rob,
Great news! Thanks for feedback!