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Websites that require authentication

Source: vignettes/example-authentication.Rmd
example-authentication.Rmd

For websites that require authentication, you can use Chromote to get screenshots by doing the following:

  1. Log in interactively and navigate to the page.
  2. Capture cookies from the page and save them.
  3. In a later R session, load the cookies.
  4. Use the cookies in Chromote and navigate to the page.
  5. Take a screenshot.

There are two ways to capture the cookies.

Method 1: Manually interact with the page

The first method uses the headless browser’s viewer. This can be a bit inconvenient because it requires going through the entire login process, even if you have already logged in with a normal browser.

First navigate to the page:

library(chromote)
b <- ChromoteSession$new()
b$view()
b$go_to("https://beta.rstudioconnect.com/content/123456/")

Next, log in interactively via the viewer. Once that’s done, use Chromote to capture the cookies.

cookies <- b$Network$getCookies()
str(cookies)
saveRDS(cookies, "cookies.rds")

After saving the cookies, you can restart R and navigate to the page, using the cookies.

library(chromote)
b <- ChromoteSession$new()
b$view()
cookies <- readRDS("cookies.rds")
b$Network$setCookies(cookies = cookies$cookies)
# Navigate to the app that requires a login
b$go_to("https://beta.rstudioconnect.com/content/123456/")
b$screenshot()

Method 2: Capture and re-use cookies

The second method captures the cookies using a normal browser. This is can be more convenient because, if you are already logged in, you don’t need to do it again. This requires a Chromium-based browser, and it requires running DevTools-in-DevTools on that browser.

First, navigate to the page in your browser. Then press CMD-Option-I (Mac) or Ctrl-Shift-I (Windows/Linux). The developer tools panel will open. Make sure to undock the developer tools so that they are in their own window. Then press CMD-Option-I or Ctrl-Shift-I again. A second developer tools window will open. (See this SO answer for detailed instructions.)

In the second developer tools window, run the following:

var cookies = await Main.sendOverProtocol('Network.getCookies', {})
JSON.stringify(cookies)

This will return a JSON string representing the cookies for that page. For example:

[{"cookies":[{"name":"AWSALB","value":"T3dNdcdnMasdf/cNn0j+JHMVkZ3RI8mitnAggd9AlPsaWJdsfoaje/OowIh0qe3dDPiHc0mSafe5jNH+1Aeinfalsd30AejBZDYwE","domain":"beta.rstudioconnect.com","path":"/","expires":1594632233.96943,"size":130,"httpOnly":false,"secure":false,"session":false}]}]

Copy that string to the clipboard. In your R session, you can paste it to this code, surrounded by single-quotes:

cookie_json <- '[{"cookies":[{"name":"AWSALB","value":"T3dNdcdnMasdf/cNn0j+JHMVkZ3RI8mitnAggd9AlPsaWJdsfoaje/OowIh0qe3dDPiHc0mSafe5jNH+1Aeinfalsd30AejBZDYwE","domain":"beta.rstudioconnect.com","path":"/","expires":1594632233.96943,"size":130,"httpOnly":false,"secure":false,"session":false}]}]'

cookies <- jsonlite::fromJSON(cookie_json, simplifyVector = FALSE)[[1]]

Then you can use Chromote to navigate to the page and take a screenshot.

library(chromote)
b <- ChromoteSession$new()

b$Network$setCookies(cookies = cookies$cookies)
b$go_to("https://beta.rstudioconnect.com/content/123456/")

b$screenshot()