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POLong polling with database data?
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copied!<p>After a week of googling and search.I am hard to find even a single tutorial about long polling from a database table instead of from a flat text file named data.text. Currently, I write manually anything in data.text and it instantly appears in the browser.</p> <p>This is the question: Long polling using database? is not answered properly even in StackOverflow. (I found a lot here but in vain.).Example of this is also here <a href="https://stackoverflow.com/questions/12460672/filemtime-alternative-for-mysql">filemtime alternative for MySQL</a></p> <p><strong>How can I modify getdata.php to make it enable for fetching data from database?</strong></p> <pre><code> $sql=mysqli_query($database,"SELECT * FROM messages where time>=$curr_date ORDER by time DESC"); while($row=mysqli_fetch_array($sql)){ $messages=$row['messages']; $id=$row['id']; echo $messages; } </code></pre> <p>Messages table is as follows</p> <pre><code> id fro to mesg time status last_modified </code></pre> <hr> <p>I am here listing an example. In this example, three files are being used.</p> <ol> <li>index.html</li> <li>getdat.php</li> <li>data.text</li> </ol> <p>Is there any need to make a fourth file to get data from database(mysql)? if not, then what type of changes are necessary in the getdata.php or data.text to use dynamic data from database?</p> <p>Here is my Javascript </p> <pre><code><script type="text/javascript" charset="utf-8"> var timestamp = null; function waitformsg() { $.ajax({ type:"Post", url:"getdata.php?timestamp="+timestamp, async:true, cache:false, success:function(data) { var json = eval('(' + data + ')'); if(json['msg'] != "") { $("#messages").append(json['msg']); } timestamp = json["timestamp"]; setTimeout("waitformsg()", 1000); }, error:function(XMLhttprequest, textstatus, errorthrown) { alert("error:" + textstatus + "(" + errorthrown + ")"); setTimeout("waitformsg()", 15000); } }); } $(document).ready(function() { waitformsg(); }); </script> </code></pre> <p>Here is the getdata.php file</p> <pre><code><?php include("../model/includes/classes.php"); $filename='data.php'; $lastmodif=isset($_GET['timestamp'])?$_GET['timestamp']:0; $currentmodif=filemtime($filename); while($currentmodif<=$lastmodif){ usleep(10000); clearstatcache(); $currentmodif=filemtime($filename); } $response=array(); $response['msg']=file_get_contents($filename); $response['timestamp']=$currentmodif; echo json_encode($response); ?> </code></pre>

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