title: How to scrape data from this website?
body: <p>I need to login to this site <a href="http://bit.do" rel="nofollow noreferrer">http://bit.do</a> for scraping purpose. Data are protected by password but I can't figure out how to log in the access them in R. </p>
  
  <p>I tried </p>
  
  <pre><code> library (rvest)
  
   url       &lt;-"http://bit.d o/#login/admin"   
   pgsession &lt;-html_session(url)               
   pgform    &lt;-html_form(pgsession)[[1]]       
  
  
   filled_form &lt;- set_values(pgform,
   'username' = "test0001", 
   'password' = "qwerty1234")
  
   submit_form(pgsession,filled_form)
  
   url &lt;- 'http://bit.d o/admin/url/http%3A||2F||2Fedition.cnn.com||2F2017||2F07||2F21||2Fopinions||2Ftrump-russia-putin-lain-opinion||2Findex.html'
   data_page &lt;- read_html(url)
   data_link&lt;- html_nodes(data_page,'td &gt; a')
   data_click&lt;- html_nodes(data_page,'td span:nth-child(1)')
  </code></pre>
  
  <p>but I get this kind of error</p>
  
  <pre><code> Submitting with 'NULL'
   Error in xml2::url_absolute(form$url, session$url) : 
   Not compatible with STRSXP: [type=NULL].
  </code></pre>
  
  <p>How could I do? These are my testing credential username: test0001, password: qwerty1234. Here's an example of protected data I want to scrape <a href="http://bit.d" rel="nofollow noreferrer">http://bit.d</a> o/admin/url/http%3A||2F||2Fedition.cnn.com||2F2017||2F07||2F21||2Fopinions||2Ftrump-russia-putin-lain-opinion||2Findex.html</p>
  
  <p>IMPORTANT: NOTE THAT DUE TO A StackOverflow RESTRICTION I PUT A SPACE BETWEEN the d and o in domain name</p>