wait_for_status.php

Linux嵌入式设计配套光盘,学习嵌入式设计可参考

<?php

/******************************************************************** 
 * Copyright (c) 2006, Graham P Phillips
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright 
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the following 
 *     disclaimer in the documentation and/or other materials provided 
 *     with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 ********************************************************************/

include_once "php_params.php";

define('LOCALHOST', '127.0.0.1');
define('LADD_PORT', 8888);
define('LOGMUXD_PORT', 8887);
define('STATUS_CHANGE_PORT', 4444);
define('MAX_WAIT_FOR_UPDATE', 10); // in seconds


// This program gets the 'ID' of what is currently being
// displayed on the browser window from the POST data.  If
// what is currently being displayed corresponds to the most
// recent events (logs), then it opens a connection to the
// logger and wait for another event.  If what is displayed
// is not the most recent event, then it returns immediately
// with the latest Laddie status and logs. You may change 
// MAX_WAIT_FOR_UPDATE above to change the periodic automatic update rate.  

  $params = read_params();
  $disp_id = array_key_exists('disp_id', $params)? $params['disp_id'] : -1;
  $curr_id = get_log_count(LOCALHOST,LOGMUXD_PORT);
 
  /* If curr_id is negative, it means that we were unable to get the current
   * log count from logmuxd.  This also means that our AJAX mechanism will 
   * not work properly. In this case, to avoid the client and server from 
   * exchanging AJAX messages very quickly, we'll handle this case the same 
   * way as when curr_id is equal to disp_id. 
   */
  if ($disp_id === $curr_id || $curr_id < 0) {
    $fp = fsockopen(LOCALHOST, STATUS_CHANGE_PORT, $errno, $errstr, 30);
    if ($fp) {
      /* block for at most MAX_WAIT_FOR_UPDATE seconds */
      stream_set_timeout($fp, MAX_WAIT_FOR_UPDATE);
      $ignore_response = fgets($fp, 128);
      fclose($fp);
    } else {
      sleep(MAX_WAIT_FOR_UPDATE);
    }
    $curr_id = get_log_count(LOCALHOST,LOGMUXD_PORT);
  }

  header("Content-Type: text/xml");
  print("<?xml version=\"1.0\" ?>\n");
  print("<laddie_status>\n");

  // Suppress Postgres error messages
  error_reporting(error_reporting() & 0xFFFD);

  // connect to the database 
  $connection = pg_connect(LOCALHOST, LADD_PORT, "");
  if ($connection == "") { 
    print("</laddie_status>\n");
    exit();
  }

  // Get and format status for all zones
  $command = "SELECT id, name, enabled, alarm FROM Zone";
  $result = pg_exec($connection, $command);
  if ($result == "") { 
    print("</laddie_status>\n");
    exit();
  }

  for($row = 0; $row < pg_NumRows($result); $row++)
  {
    $id    = pg_result($result, $row, 0);
    $name  = pg_result($result, $row, 1);
    $enabled = pg_result($result, $row, 2);
    $alarm   = pg_result($result, $row, 3);
    printf("<zone id=\"%s\" name=\"%s\" enabled=\"%s\">", $id, $name, $enabled);
    printf("%s</zone>\n", $alarm);
  }

  // free the result for the status, close conn to Ladd
  pg_freeresult($result);
  pg_close($connection);


  // Give current log count
  printf("<logcount>%d</logcount>\n", $curr_id);

  // connect to the RTA interface on the logger
  $connection = pg_connect(LOCALHOST, LOGMUXD_PORT, "");
  if ($connection == "") { 
    print("</laddie_status>\n");
    exit();
  }
  // Get and display the most recent log messages
  // The number 5 is arbitrary, based on how many log
  // messages the web UI wishes to display. 
  $command = "SELECT log FROM TblDest LIMIT 5";
  $result = pg_exec($connection, $command);
  if ($result == "") { 
    pg_close($connection);
    print("</laddie_status>\n");
    exit();
  }

  // print each log message as a <log>
  $nrow = pg_NumRows($result);
  for($row = 0; $row < $nrow; $row++)
  {
    $log = pg_result($result, $row, 0);
    print("<log>$log</log>\n");
  }
  // free the result for the log display
  pg_freeresult($result);
  pg_close($connection);

  print("</laddie_status>\n");
?>