BCC-16 (in Chinese) 計算機概論十六講 R -- PHP Example 2

R 教材：PHP Example 2

Example 2 -- PHP display the plot created by R

This page is for Linux only!!

PHP code (ex_2.php)

<?

  $cmd = "echo 'argv <- \"ex_2.r\"; source(argv)' | " .
         "/usr/bin/R --vanilla --slave";

  $handle = popen($cmd, "r");
  $ret = "";
  do{
    $data = fread($handle, 8192);
    if(strlen($data) == 0){
      break;
    }
    $ret .= $data;
  }
  while(true);
  pclose($handle);

  echo $ret;

?>

This PHP file use shell command 'echo' pipe arguments to R and accept the return image from R and show it on web page.

R script (ex_2.r)
If the "ex_2.r" as the follows, it will return a rainbow pie chart.

  dev.off.wrap <- function(){
    dev.off()
    invisible()
  }

  bitmap(file = "%stdout", type="png256")
  pie(rep(1, 24), col = rainbow(24))
  dev.off.wrap()

This R script just print the arguments.

Browse
Put the "ex_2.php" and "ex_2.r" into the same directory and open web browser to link "ex_2.php".
Click here to see the pie chart from R script ex_2.r.


	陳韋辰 (04/08/19) ---