<?php
  /**
   * vzapi helper functions
   * $Header: /home/wf/youless/RCS/vzapihelper.php,v 1.3 2014/05/30 06:57:23 wf Exp $
   */

  /**
   * get a curl channel
   */
  function curl($url) {
    //  Initiate curl
    $ch = curl_init();
    // Disable SSL verification
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    // Will return the response, if false it print the response
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    // Set the url
    curl_setopt($ch, CURLOPT_URL,$url);

    return $ch;
  }
  
  /**
   * read the given url
   * @param $url:the url to read from
   */
  function readUrl($url)  {
    $ch=curl($url);
    
    // Execute
    $result=curl_exec($ch);
    return $result;
  }
  
  /**
   * post to the given url
   */
  function postUrl($url,$fields) {
     $ch=curl($url);
     $fields_string="";
     //url-ify the data for the POST
    foreach($fields as $key=>$value) { 
      $fields_string .= $key.'='.$value.'&'; 
    }
    rtrim($fields_string, '&');
    curl_setopt($ch,CURLOPT_POST, count($fields));
    curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);  
    $result=curl_exec($ch);
    return $result;
   }

   /**
    * post data to vz middleware
    *   param 1: vzurl - middleware url of volkszaehler
    *   param 2: channel uuid 
    *   param 3: value to post
    */
   function post2vz($vzurl,$cuuid,$value,$debug=false) {
     // post data to middleware according to: 
     // http://wiki.volkszaehler.org/development/api/reference

     // adapt timestamp to volkszaehler conventions
		 $timestamp=time()*1000;

     # first 
     $posturl=$vzurl."/".$cuuid.".json";
     $fields=array("ts"=>$timestamp,"value" => $value );
     $presult=postUrl($posturl,$fields);
     if ($debug) {
       echo $presult;
     }
   }

  /**
   * check that option $opt is available in $options
   * return the value if available
   */
  function checkoption($opt,$options) {
    if (array_key_exists($opt,$options))
      return $options[$opt];
    else
      die("option $opt missing!\n");
  }

?>