Take screenshot

[Anarchist666]

The CaptureScreenshotResult has one named field _screenshotData :: String. The Page.captureScreenshot should be used with onEvent or waitFor?

[Anarchist666]

Already found out.

[Anarchist666]

It turned out like this:

import Control.Monad.Trans (liftIO)
import Data.Foldable (traverse_)
import Chrome.Target.Client
import Chrome.Target.Async (waitFor, onEvent, stopEventListener)
import qualified Chrome.API.Page as Page
import qualified Chrome.API.Page.Types as PageTypes
import qualified Chrome.API.Network as Network
import Data.ByteString.Base64 (decode)
import Data.ByteString as B
import Data.ByteString.Char8 as C8

takeScreenshot :: String -> String -> TargetClient ()
takeScreenshot url outputFileName = do
    traverse_ waitFor [Page.enable, Network.enable Network.defaultEnableParams]

    let screenshotParams = PageTypes.CaptureScreenshotParams "png" 0 True

    waitFor $ Page.navigate url
    waitFor $ Page.onLoadEventFired
    result <- waitFor $ Page.captureScreenshot screenshotParams
    liftIO $ writeData result

    traverse_ waitFor [Page.disable, Network.disable]

    where
        writeData (Left error)  = print error
        writeData (Right event) = writeDecodedData . decode . C8.pack $ PageTypes._screenshotData event
        writeDecodedData (Left error) = print error
        writeDecodedData (Right event) = B.writeFile outputFileName event