session function

Simulate a session in web browser

This set of functions allows you to simulate a user interacting with a website, using forms and navigating from page to page.

• Create a session with session(url)
• Navigate to a specified url with session_jump_to(), or follow a link on the page with session_follow_link().
• Submit an html_form with session_submit().
• View the history with session_history() and navigate back and forward with session_back() and session_forward().
• Extract page contents with html_element() and html_elements(), or get the complete HTML document with read_html().
• Inspect the HTTP response with httr::cookies(), httr::headers(), and httr::status_code().

session(url, ...)

is.session(x)

session_jump_to(x, url, ...)

session_follow_link(x, i, css, xpath, ...)

session_back(x)

session_forward(x)

session_history(x)

session_submit(x, form, submit = NULL, ...)

Arguments

• url: A URL, either relative or absolute, to navigate to.

• ...: Any additional httr config to use throughout the session.

• x: A session.

• i: A integer to select the ith link or a string to match the first link containing that text (case sensitive).

• css, xpath: Elements to select. Supply one of css or xpath

  depending on whether you want to use a CSS selector or XPath 1.0 expression.

• form: An html_form to submit

• submit: Which button should be used to submit the form?

  • NULL, the default, uses the first button.
  • A string selects a button by its name.
  • A number selects a button using its relative position.

Examples

s <- session("http://hadley.nz")
s %>%
  session_jump_to("hadley-wickham.jpg") %>%
  session_jump_to("/") %>%
  session_history()

s %>%
  session_jump_to("hadley-wickham.jpg") %>%
  session_back() %>%
  session_history()

s %>%
  session_follow_link(css = "p a") %>%
  html_elements("p")