learn2earn has asked for the wisdom of the Perl Monks concerning the following question:

I have a need to scrape a page for a temperature readout and send an alert if the temperature reaches a certain threshold, this device (a sensor in our server room) does create a webpage but I would like to trigger an alarm if the temperature gets too high. What would be the best way to go about doing this.

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Re: scraping temperatures
by gman (Friar) on Feb 10, 2010 at 19:33 UTC

    I would look to do this with Net::SNMP rather then a web get. See if you can perform an snmpwalk on the sensor device. If not LWP LWP basics should get you started.

[reply]
Re: scraping temperatures
by learn2earn (Acolyte) on Feb 10, 2010 at 21:48 UTC
    net snmp looks confusing I am not sure how to use that, for the time being as this is a necessity to do quick, I was going to try scraping the page periodically,I have a piece that downloads the page, and one that sends an email so now I need a regex that will find the temperature and send a message if its too high. the temperature is like this in the page.. 66.1 °F how would I do a regex for this? would something like this work? 
    my $temp=~/dd*&degF/
if $temp>="75&degF" 
send a message code here..

    [download]
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[d/l]
      How about the following? The variable $text should contain the text you want to check. 
      if(
 $text =~ 
  m{ 
     (         #open capturing parenthesis
         \d+   #numbers before the period
         \.    #literal period
         \d+   #numbers after period
     )         #closing capturing parenthesis
     \s*       #optional spaces
     °     #degree symbol
     F         #literal letter F
  }xms){
     my $temp = $1;   # '$1' is what was found in capturing ()
     if($temp > 75){
         #code to send message
     }
}else{
    #code to deal with not finding temperature data.
}

      [download]
      or without comments 
      if( $text =~ m{ (\d+ \. \d+) \s* ° F }xms){
     my $temp = $1;
     if($temp > 75){
         #code to send message
     }
}else{
    #code to deal with not finding temperature data.
}

      [download]
      Note: Updated several times
[reply]
[d/l]
[select]
        Thanks molecules! I found the error(s)I had its working now.
[reply]

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