it might just be too late at night for me to see a clear solution here, but I figured I'd get some thoughts from anybody with an opinion...
the site i'm working on has a long list of user posts. i've got all the scroll event handlers working to ajax in the next batch of 100 posts when you reach or approach the bottom.
my question is... How do i prevent the following scenario?
UserX visits the site and loads posts 1-100
10 more users visit the site and add 10 more posts
UserX scrolls to bottom and loads posts 101-200, which used to to be posts 91-190
UserX ends up with duplicates of posts 91-100 on the page
i'll include a stripped down version of my code below in case it helps anybody else along
$.ajax({
type:'POST',
url:"/userposts.php",
data:{ limit: postCount },
success:function(data) {
$("postsContainer").append(data);
if ( $("postsContainer").find("div[id='lastPostReached']") ) {
// unbind infinite scrolling event handlers
}
},
dataType:'html'
});
in my PHP script I have essentially the following:
if ( ! isset($_POST["limit"]) ) {
$sql .= " LIMIT 101"; // initial request
} else {
$sql .= " LIMIT {$_POST["limit"]},101
}
$posts = mysql_query($sql);
while( $post = mysql_fetch_assoc($posts) ) {
/* output formatted posts */
}
// inform callback handler to disable infinite scrolling
if ( mysql_num_rows($posts) < 101 ) {
echo '<div id="lastPostReached"></div>';
}
This gives me infinite scrolling nice and easy, but how can I prevent the hypothetical duplicates that would show up when new records have been added to the table between ajax requests?
You define a timestamp from php that indicates the servertime at the time the page loads (eg var _loadTime = <?php echo time(); ?>) and then pass this value as part of the Ajax data config object along with limit.
Then on the server side you can exclude any posts that were created after this time and hense preserve your list.
You can also go a step further and use this time along with a basic ajax long polling technique to notify the user of new posts since the page loaded/last loading of new posts - similar to Facebook and Twitters feeds.
Update your ajax request, so that in addition to the limit parameter you pass through the current range of post ids (I'm assuming the posts have some kind of unique id). Update your php to take those parameters into account when retrieving the next set of posts.
That is, instead of saying "give me another 100" the request is "give me 100 starting at id x".
(Sorry, I don't have time now to write an example code for this.)
Just use a unique identifier ID for the posts and count backwards.
First visit user requests posts 603-503
Ten users get on the page and add comments so the highest comment is now 613
User scolls down and requests 503-403
Problem solved? :)
Related
I want to add "live notifications" feature for my users: When they receive a new message(via the chat system) then display a notification badge on the chat icon in the navbar.
I was thinking to do: AJAX calls with setInterval:(As seen on another post here)
The AJAX call:
setInterval('checkUpdates', 2000);
function checkUpdates() {
$.get('/check_updates.php?timestamp=' . lastTime, function (results){
// do stuff here
}
);
The PHP code:
$timestamp = $_REQUEST['timestamp'];
$results = query('SELECT message FROM messages WHERE messageTime > "$timestamp"');
echo fetch($results);
I have a few questions before:
1) Since I want the update-checking to be constantly running, and the navbar is always present (always on the top of the page), is the navbar.php file the correct place to put that AJAX call?
2) How badly does that affect performance of the website, to have AJAX calls constantly running every 2 seconds?
3) Is there a better way? Do websites like Facebook have an efficient way to immediately popup the chat window whenever you get a new message, or it's thanks to their huge amount of servers?
Thanks
Hello i've serched a lot without find an answer to this.
is possible to retrieve Fb posts of a certain public page starting from a post id?(for example tomorrow start collecting posts from the last post of today)
Let's take for example Bill Gates page
the idea would be to do something similar to:
$id = 216311481960; //Bill's fb id
$last_post = 10153219939326961 // last bill posts
try {
$request= $id.'/posts?since='.$last_post.'&access_token=xxxxxxxxxxxxxxxxxxxx|xxxxxxxxxxxxxxx-xxxxxx';
$search = $fb->get($request);
if (isset($search)){
//do something
}
}
catch(Exception $e) {
echo 'Message: ' .$e->getMessage()."<h1>".$id."</h1>";
}
obviously since parameter has to be a date and that code wont work.
Any Idea?
Thanks in advance.
Edit
i try to search for all posts of a specific Facebook user starting not at a certain date but from a certain post, lets say that today i grab users postid1,postid2,postid3 (postid3 is the last post i've taken, and i save that id) next time i would to grab new posts published after postid3 (since postid3)
You can do it in the url, I just made it work recently. This is from a python code, but the URL should work the same way.
"https://graph.facebook.com/?ids=" + ids[:-1] +
"&fields=name,posts.limit(5).since(10+days+ago)" +
"{from,to,full_picture,message,caption,description," +
"link,name,shares,likes.summary(true)," +
"comments.summary(true),created_time,is_hidden," +
"message_tags,place,type,with_tags}")
This will get the last 5 posts from the last 10 days for several page ids. It will also get the total number of likes and comments as summary.
It took me a while to dig this info from the net, I found that since= has changed to since().
I tried to retrieve some reference where it's documented, so far with no success. I'll give you an update if I find it.
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;
$sec++;
sleep(one sec here);
}
Use sleep for 10 secs in order to check every 10 secs...
I have a PHP page that uses jQuery to let a user update a particular item without needing to refresh the page. It is an availability update where they can change their availability for an event to Yes, No, or Maybe. Each time they click on the link the appropriate jQuery function is called to send data to a separate PHP file (update_avail.php) and the appropriate data is returned.
Yes
Then when clicked the params are sent to a PHP file which returns back:
No
Then, if clicked again the PHP will return:
Maybe
It all works fine and I'm loving it.
BUT--
I also have a total count at the bottom of the page that is PHP code to count the total number of users that have selected Yes as their availability by simply using:
<?php count($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);
}
...
I was wondering if it was possible to query the following:
List of (all) users who like my facebook page, and
Additional information those users have made publicly available (beyond first and last name)
Basically looking to generate detailed marketing stats of users who like my facebook page, if possible. Any suggestions or alternatives welcome.
Thank you.
I am afraid this is NOT possible, follow this bug for more information.
Another proof is the page_fan table you will notice that only the uid field is indexable so you need to know the user id to search it and not the page_id, as you know if a user "likes" a page this would mean he is a "fan" of that page.
After being actively working with the Facebook API for a while now, and following the announcements and API releases (and deprecations) along with the introduction and changes of policies, I can understand that Facebook will only share info about their users by letting them explicitly do so (a.k.a interact/authorize your Apps).
And hence the best thing to do in the absence of such feature is:
Understand your audience through Page Insights
Collect fans interests & info by creating custom apps through Page Tabs and using other Facebook features like Questions
Alright, nobody wants to break Facebook's TOS but they have tied our hands on our own basic data. So, scraping is illegal, but not saving a page. What I have done (and note that I needed this for offline purpose anyway):
Go to https://www.facebook.com/browse/?type=page_fans&page_id={FAN PAGE ID}
Scroll down until you have all of your fans. Save this page on your local machine, let's say, Facebook.html.
Now, using ruby and nokogiri:
require 'nokogiri'
>true
f = File.open('/your_path/Facebook.html')
doc = Nokogiri::HTML.parse(f.read)
doc.xpath('//div[#class="fsl fwb fcb"]/a').each {|link| puts link.content}
Do a graph search likes this: "People who like [your fanpage's name]". You will all the result.
Then create shortcut on your browser with this javascripts code, it will click on the View more link and scrolling until all result are shown in the page:
javascript: i = 0;minutes = 30;counter = minutes * 60;function repeatScroll() {
if (i < counter) {window.scrollTo(0, document.body.scrollHeight);i++;}
setTimeout(repeatScroll, 1000);}repeatScroll();
After that, create other shortcut and run this js code to retrieve all UID from the search result:
javascript:var txt="";e=document.getElementsByClassName("FriendRequestOutgoing");
for(var i=0; i<e.length; i++) {v=e[i].getAttribute("data-profileid");
if(v) txt+=v+"\n"}document.body.innerHTML="<textarea>"+txt+"</textarea>";
A textarea box will appear in the screen with all uid inside. Just copy it to your notepad and import into your Custom Audience in Facebook Ad Manager.
I created and use this code everyday to get all UID with criterial I need.
You can launch any graph search you want.
This is homemade code, so using it without your own responsibility :)
Enjoy them.
It's possible, just not with FQL anymore.
Do a GET of https://www.facebook.com/browse/?type=page_fans&page_id={FAN PAGE ID} and scrape out the users.
Viola.
Now you can get people on your page with this link, or click on Settings button, than on People on the left sidebar. https://www.facebook.com/[PAGENAME]/settings/?tab=people_and_other_pages
If you want to get all the user's photo, press F12 and add these codes to the Console:
javascript:i=0;minutes=30;counter=minutes*60;function repeatScroll(){if(i<counter){window.scrollTo(0, document.body.scrollHeight);i++;}setTimeout(repeatScroll,1000);}repeatScroll();
than, when you reached the bottom of the page:
javascript:var txt="";e=document.getElementsByClassName("img"); for(var i=0; i<e.length; i++) {v=e[i].getAttribute("src"); if(v) txt+="<img src='"+v+"'>\n"}document.body.innerHTML="<textarea>"+txt+"</textarea>";
To display photos: create a HTML page and first insert these lines into that file:
<meta charset="utf-8">
<style>img { width:21px; margin:-1px; }</style>
<div style="width:851px; height:315px;background-color:white;">
<!-- PASTE HERE PHOTOS' CODE YOU GET -->
<span style="color:#3B5998;font-weight:bold;font-size:20px;margin-bottom:4px;">600 like, thank you!</span>
<!-- PASTE HERE PHOTOS' CODE YOU GET -->
</div>
Then create shortcut on your browser with this javascript code, it will click on the View more link and scrolling until all result are shown in the page:
i = 0;
minutes = 30;
counter = minutes * 60;
function repeatScroll() {
if (i < counter) {
window.scrollTo(0, document.body.scrollHeight);
i++;
}
setTimeout(repeatScroll, 1000);
}
repeatScroll();
After that, create other shortcut and run this js code to retrieve all UID from the search result:
var e=document.getElementsByClassName("fsl fwb fcb");
var ids = [];
for(var i = 0 ; i < e.length; i++){
ids.push(JSON.parse(e[i].childNodes[0].getAttribute("data-gt")).engagement.eng_tid);
}
console.log(ids);
load all list
i = 0;
minutes = 30;
counter = minutes * 60;
function repeatScroll() {
if (i < counter) {
window.scrollTo(0, document.body.scrollHeight);
i++;
}
setTimeout(repeatScroll, 1000);
}
repeatScroll();
get id
var e=document.getElementsByClassName("_3cb8");
var ids = [];
for(var i = 0 ; i < e.length; i++){
ids.push(e[i].getAttribute("href"));
}
console.log(ids);
You can get it using facebook open graph.
https://graph.facebook.com/<your-page-name-or-page-id>/likes
For example :
https://graph.facebook.com/chickfila/likes
You need to send graph api call using "id" for more detail about user who like you page.
However, this call will retrieve the other Facebook objects that the page (Chickfila) has liked, NOT the users who have liked the Chickfila page.