I'd like get the time when the actual webpage has been loaded or refreshed.
I've tried http request but there is no such information.
After page is loaded ajax function checks new messages every 60 seconds. I need to show only new ones (the ones that have been posted after the page load).
Thanks a lot in advance.
Timestamp every message. In your AJAX function, send a parameter of the last message you already have. Return only messages newer than that. E.g., the AJAX URL you hit can look something like /get_messages.php?newer_than=1343041382.
As #DaveRandom mentioned:
You just need to store the result of time() in $_SESSION - e.g. $_SESSION['lastPoll'] = time();. Then every time you poll the server for new messages "SELECT * FROM messages WHERE message_time > ".$_SESSION['lastPoll'], and update the stored value with the new time()
Assuming you store the time the message was sent in the database, and that you store it as a timestamp, you could use something like this:
When the page is loaded, you could save the current time as this:
$page_load_time = time();
Then just send the $page_load_time to your file that is loaded with AJAX, using post or get, and then in the PHP-file loaded with AJAX, you could do an SQL-query that gets all the new messages. Maybe something like this:
$sql = "SELECT * FROM `messages` WHERE `time` > '{$page_load_time}'
Related
I have a index.html file consist of certain data with refresh button.
On pressing refresh button it will call refresh.php.
Refresh.php connects database and gets new updated data from database (Say- today's event data) And shows updated data in that refresh.php page
this is what I do.. But I want dynamic home page and want to remove refresh button. In short- whenever user loads homepage..that division should display updated data from database. So should I use .index.php and use php code in index.php itself will work?
I dont want to use asp/ajax/cookie/session. Please give me idea apart from these. Thanks :)
You could check the file's age, e.g.
<?php
$ca_file = '/path/to/foo.blah';
if (is_file($ca_file)) {
// check if file is not older then 1 hour
if (time() - filemtime($ca_file) <1 * 3600) {
$ca_news = 'y';
}
}
That would check if the file is not older then 1 hour. You'll probably want something smaller. Now all you need to do is to check the value of $ca_news and do your magic.
I am making a php chat and am starting the php checking database part. So when a user types something into the chat, it gets recorded in the MySQL database, how would I check the database every 10 seconds so that one user's chat would update with new messages from other users. I know that you can use an ajax request to a page with an interval, but I want the php to be on the same page, instead of having to use numerous pages. This is the code for checking the database
<?php
$con = mysqli_connect('host','user','pass','database');
$query = mysqli_query($con,"SELECT * FROM `messages`");
while ($row=mysqli_fetch_assoc($query)) {
$user = $row['user'];
$message = $row['message'];
echo 'User: ',$user,' Message: ',$message;
}
?>
Thanks in advance anyone!
Use MySQL Event Scheduler.
Below link will guide you through .
http://www.9lessons.info/2012/10/mysql-event-scheduler.html.
I think best option in your case .
AJAX is probably the simplest solution. You can perform an AJAX request on the same page your PHP code is executing on if you really want to.
(function check() {
$.get('mypage.php', function(data) {
doSomethingWith(data);
setTimeout(check, 5000); // every 5 seconds
});
})();
PHP doesn't have a setInterval function. While I'm sure you can use a crontask to automate it on the server, you can also achieve this with some simple Javascript.
The concept you are trying to achieve is known as Short Polling. What you want to do is to have a setInterval function in Javascript that constantly makes AJAX requests to your PHP file which performs the check to the database for new messages. Your PHP should return that information to your script where you can then simply populate the user's screen.
There is also Long Polling where you simply maintain the connection and have a setTimeout to wait for messages to come in. You can find more information yourself and if you have questions, you can come back here.
A good video about this:
https://www.youtube.com/watch?v=wHmSqFor1HU
Hope this helps.
This is what you need. We need set time for ajax auto reload. Don't put everything in one page. Because you must reload page to refresh data. That is bad solution.
Call jQuery Ajax Request Each X Minutes
Make a while for 30 seconds, and check the db every second, once you find a record the while is being broken, also it is being broken when 30 secs are expired.
$sec = 1;
while($sec <= 30) {
if(has record)
Send to the user;
$sec++;
sleep(one sec here);
}
Use sleep for 10 secs in order to check every 10 secs...
Here is my code
i have html link like this
<?php echo $pro_name;
these php values coming from database it has (thousands of) number of results, here i need to set cookie for this links.
If its clicked means i need to store that links in cookie and i need to show last five viewed links in another page.
If I understand, you just need to bind the setting of a cookie to the clicking of the link?
If so, you need to add an ID to your <a>:
In English
Then bind some cookie-setting code to the click event:
(Using jQuery)
$("a#mylink").bind("click", function() {
$.cookie("TR_LNG", "English");
});
Edited. Set expires time(for example for 30 minutes):
30 minutes is 30 * 60 * 1000 miliseconds. Add that to the current date to specify an expiration date 30 minutes in the future.
var date = new Date();
var minutes = 30;
date.setTime(date.getTime() + (minutes * 60 * 1000));
$.cookie("example", "foo", { expires: date });
You don't need cookies for this. If I undertsand your problem, you simply need to keep track of the last N requests to your app from a certain user. You need users to be associated with a session, and at the top of each and every page you want to track you need to:
session_start();
$hits = $_SESSION['last_hits'];
array_push($_SESSION['last_hits'], getExternalUrl());
if (count($hits) > 5) {
array_shift($hits);
}
You'd better implement a framework instead of manually adding this snippet at the top of every PHP file. Also note that I used getExternalUrl() because if the PHP server is reverse proxied, the request path may not contain the actual URL (not sure what you really need, tough). Appending the page token to the query string may be ok, too, but it all depends on your needs.
I'm looking into doing some long polling with jQuery and PHP for a message system. I'm curious to know the best/most efficient way to achieve this. I'm basing is off this Simple Long Polling Example.
If a user is sitting on the inbox page, I want to pull in any new messages. One idea that I've seen is adding a last_checked column to the message table. The PHP script would look something like this:
query to check for all null `last_checked` messages
if there are any...
while(...) {
add data to array
update `last_checked` column to current time
}
send data back
I like this idea but I'm wondering what others think of it. Is this an ideal way to approach this? Any information will be helpful!
To add, there are no set number of uses that could be on the site so I'm looking for an efficient way to do it.
Yes the way that you describe it is how the Long Polling Method is working generally.
Your sample code is a little vague, so i would like to add that you should do a sleep() for a small amount of time inside the while loop and each time compare the last_checked time (which is stored on server side) and the current time (which is what is sent from the client's side).
Something like this:
$current = isset($_GET['timestamp']) ? $_GET['timestamp'] : 0;
$last_checked = getLastCheckedTime(); //returns the last time db accessed
while( $last_checked <= $current) {
usleep(100000);
$last_checked = getLastCheckedTime();
}
$response = array();
$response['latestData'] = getLatestData() //fetches all the data you want based on time
$response['timestamp'] = $last_checked;
echo json_encode($response);
And at your client's side JS you would have this:
function longPolling(){
$.ajax({
type : 'Get',
url : 'data.php?timestamp=' + timestamp,
async : true,
cache : false,
success : function(data) {
var jsonData = eval('(' + data + ')');
//do something with the data, eg display them
timestamp = jsonData['timestamp'];
setTimeout('longPolling()', 1000);
},
error : function(XMLHttpRequest, textstatus, error) {
alert(error);
setTimeout('longPolling()', 15000);
}
});
}
Instead of adding new column as last_checked you can add as last_checked_time. So that you can get the data from last_checked_time to the current_time.
(i.e) DATA BETWEEN `last_checked_time` AND `current_time`
If you only have one user, that's fine. If you don't, you'll run into complications. You'll also run one hell of a lot of SELECT queries by doing this.
I've been firmly convinced for a while that PHP and long polling just do not work natively due to PHP not having any cross-client event-driven possibilities. This means you'll need to check your database every second/2s/5s instead of relying on events.
If you still want to do this, however, I would make your messaging system write a file [nameofuser].txt in a directory whenever the user has a message, and check for message existence using this trigger. If the file exists and is not empty, fire off the request to get the message, process, feed back and then delete the text file. This will reduce your SQL overhead, while (if you're not careful) increasing your disk IO.
Structure-wise, an associative table is by far the best. Make a new table dedicated to checking the status, with three columns: user_id message_id read_at. The usage should be obvious. Any combination not in there is unread.
Instead of creating a column named last_checked, you could create a column called: checked.
If you save all messages in the database, you could update the field in the database. Example:
User 1 sends User 2 a message.
PHP receives the message using the long-polling system and saves the message in a table.
User 2, when online, would send a signal to the server, notifying the server that User 1 is ready to receive messages
The server checks the table for all messages that are not 'checked' and returns them.
I have a PHP page that uses jQuery to let a user update a particular item without needing to refresh the page. It is an availability update where they can change their availability for an event to Yes, No, or Maybe. Each time they click on the link the appropriate jQuery function is called to send data to a separate PHP file (update_avail.php) and the appropriate data is returned.
Yes
Then when clicked the params are sent to a PHP file which returns back:
No
Then, if clicked again the PHP will return:
Maybe
It all works fine and I'm loving it.
BUT--
I also have a total count at the bottom of the page that is PHP code to count the total number of users that have selected Yes as their availability by simply using:
<?php count($event1_accepted); ?>
How can I make it so that if a user changes their availability it will also update the count without needing to refresh the page?
My thoughts so far are:
$var = 1;
while ($var > 0) {
count($day1_accepted);
$var = 0;
exit;
}
Then add a line to my 'update_avail.php' (which gets sent data from the jQuery function) to make $var = 1
Any help would be great. I would like to stress that my main strength is PHP, not jQuery, so a PHP solution would be preferred, but if necessary I can tackle some simple jQuery.
Thanks!
In the response from update_avail.php return a JSON object with both your replacement html and your new counter value.
Or to keep it simple, if they click "yes" incriment the counter, if they click No or maybe and their previous action wasn't No or Maybe decrease the counter.
Assuming your users are logged into the system I'd recommend having a status field in the user table, perhaps as an enum with "offline", "available", "busy", "unavailable" or something similar and use the query the number of available users whilst updating the users status.
If you were to do this you'd need to include in extend your methods containing session)start() and session_destroy() to change the availability of the user to available / offline respectively
The best way is the one suggested by Scuzzy with some improvements.
In your php, get the count from the database and return a JSON object like:
{ count: 123, html: 'Yes' }
In your page, in the ajax response you get the values and update the elements:
...
success: function(data) {
$("#linkPlaceholder").html(data.html);
$("#countPlaceholder").html(data.count);
}
...