• Guy

Dot Matrix printer fed a continuous stream of paper, to print tweets which contain a search term in near realtime.

• Script that polls the Twitter API for tweets with a given keyword

Interval ?

Need to sanitise text ?

http://search.twitter.com/search.json?q=hacman&since_id=1520639490

• Parses returned JSON and populates message queue

 search(id,value);  message_queue(message_id,search_id,time,from_user,from_user_id,to_user_id,message);  last_message(search_id,message_id);

• Arduino calls a script that returns the next message

return ascii string containing CR and LF that can be streamed straight to the printer

Test implementation of reading data from Twitter API and parsing it: http://www.thouret.co.uk/jsontest.php?q=stockport

MySQL database schema as in blueprint created.

Script now in place and run by cron every 5mins to populate the message_queue table:

  # Twitter Poller
  # Guy Thouret
  # 9/2/2010

  # get_url function
    function get_url($url) {
      $ch = curl_init();
      curl_setopt($ch,CURLOPT_URL,$url);
      curl_setopt($ch,CURLOPT_RETURNTRANSFER,
      curl_setopt($ch,CURLOPT_CONNECTTIMEOUT,
      $content = curl_exec($ch);
      curl_close($ch);
      return $content;
    }

    # Script constants
    $debug      = false;
    $twitter_search_api = "http://search.twitter.com/search.json";
    $dbhost     = 'localhost';
    $dbuser     = 'xxxx';
    $dbpass     = 'xxxx';
    $dbname     = 'feedprinter';

    # DB Connection
    $conn = mysql_connect($dbhost, $dbuser, $dbpass) or die('Error connecting to mysql');
    mysql_select_db($dbname);

    # Perform Searches
    $q = "SELECT * FROM search";
    $r = mysql_query($q);

    while ($row = mysql_fetch_assoc($r)) {
        # Get Last ID
        $q2 = "SELECT message_id FROM last_message WHERE search_id = ".$row['id'];
        $r2 = mysql_query($q2);
        $row2 =  mysql_fetch_assoc($r2);

        $last_id = $row2['message_id'];
        if ($debug) {
            echo "lastid=".$last_id;
        }
        print_r($row2);

        $json_result = get_url($twitter_search_api."?q=".$row['value']."&since_id=".$last_id);
        $result = json_decode($json_result);

        $last_id = 0;
        foreach ($result->results as $tweet) {
            $q3 = "INSERT INTO message_queue VALUES ('".$tweet->id."','".$row['id']."','".$tweet->created_at."','".$tweet->from_user."','".$tweet->from_user_id."','".$tweet->to_user_id."','".$tweet->text."')";
            $r3 = mysql_query($q3);
            if ($debug) {
                echo $q3;
            }
            if ($tweet->id > $last_id) $last_id = $tweet->id;
        }

        if ($last_id != 0) {
            $q4 = "UPDATE last_message SET message_id=".$last_id." WHERE search_id=".$row['id'];
            $r4 = mysql_query($q4);
        }
    }

    mysql_close($conn)

Category:Projects