You need to do GET request first, to get the value of input field wpLoginToken.

  my $req;
  my $response;

  $req = "$wikiurl?title=Special:UserLogin&returnto=Main+Page";
  print "req = GET $req\n";
  $response = $ua->request(
      GET $req,
      );
# look for for cookie-set request from server, ie.  mediawiki_isg_sess
+ion=954d4797c18ca9054f14c2675af3255e; path=/; HttpOnly
#
  foreach (keys %{$response->{'_headers'}}) {
    if ($_ =~ /^set-cookie$/i) { # server attempting to set a cookie
      my $c = $response->{'_headers'}->{$_};
      print "Server header set-cookie = $c\n";
    }

  }

  my @lines = split /\n/, $response->content();
  foreach (@lines) {
    if (/name="wpLoginToken" value="([0-9a-z]+)"/)
    {
      my $token = $1;
      $params{'wpLoginToken'} = $token;
      print "found token=$token, line=$_\n";
    }
  }
  $cookie_jar->extract_cookies( $response );
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Then, you need to pass this in your next request when you are actually logging in, when submitting the username and password

  $req = $wikiurl."?title=Special:UserLogin&action=submitlogin&type=lo
+gin&returnto=Main+Page";
  print "req = POST $req\n";


  $params{'wpLoginAttempt'} = "Log in";
  $response = $ua->request(
    POST $req,
    Content_Type => 'application/x-www-form-urlencoded' ,
    Content => [ %params ]
    );

  $loggedIn = 0;
  foreach (keys %{$response->{'_headers'}}) {
  #  print "ServerHeader: ".$_."\n";
    if ($_ =~ /^set-cookie$/i) { # server attempting to set a cookie
      my $a = $response->{'_headers'}->{$_};
      if ($a =~ /^ARRAY(.+)$/) {
        foreach (@{$a}) {
          print "Server header set-cookie: ======== $_\n";
          if (/UserID=\d+\;/i) {
            $loggedIn = 1; # Success!
              last;
          }
        }
      }
    }
  }

  print "Login result = $loggedIn\n";
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Now, you will need the get and keep passing the editToken

  my $LastEditToken = undef;

  my $body = $response->content();
  if ($body =~ /value="([0-9a-z\+\\]+)"\s+name="editToken"/)
  {
    $LastEditToken = $1;
    print "found token=$LastEditToken\n";
  }
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Whenever you want to do anything further with the wiki, keep pasing the editToken, eg. for importing XML dumps:

sub importXML
{
  if (not defined $LastEditToken)
  {
    my $response = $ua->request(
       GET "$wikiurl?title=Special:Import",
       );
    if ($response->content() =~ /value="([0-9a-z\+\\]+)"\s+name="editT
+oken"/)
    {
      $LastEditToken = $1;
      print "==found token=$LastEditToken\n";
    }
  }

  my $url = "$wikiurl?title=Special:Import&action=submit";
  print "Sending request to $url,\n   using token $LastEditToken\n";
  my $response = $ua->request(
      POST "$url",
      Content_Type => 'multipart/form-data',
      Content =>
      [
        'action' => 'submit',
        'source' => 'upload',
        'editToken' => $LastEditToken,
        'MAX_FILE_SIZE' => $MaxXmlSize,
        'xmlimport' => [$filepath],
      ]
      );
  if ($response->is_success) {
    if ($response->content() =~ /value="([0-9a-z\+\\]+)"\s+name="editT
+oken"/)
    {
      $LastEditToken = $1;
      print "==found token=$LastEditToken\n";
    }
    return 1;
  } else {
    return 0;
    print $response->content();
  }
}
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