I'm making a small php game for school. It has to be some kind of multiplayer game called four in a row/four in a line, whatever you want to name it.
Because its a multiplayer game and my playing field is saved in a database, I want to refresh the 'gamefield' if a user is making an action on the page. Like if he inserts a chip in the field, the other user must see it as well, and they have to switch turns. So how can I refresh the page on both computers/browsers when only 1 person is making an action on that page? So that both computers/browsers see the newly inserted chip in the field and the switching of a turn?
The web server usually do not initiate connexions to the browsers. You can check periodically from all computers/browsers if the state of the game changed. Ajax probably fits your need.
Use setTimeOut() or setInterval() to call a function, which makes a AJAX request for a field update. I would also advise to use jQuery to avoid writing everything from scratch.
Related
I'm making a simple mobile web app where users should be able to login/authenticate to sign up for private events.
I love the way JQuery mobile looks and feels, but want PHP to do everything in the backend: Handle form processing, talk to the DB and so on.
I currently have no authentication, but want to add that.
Wrapping the current solution in Phonegap actually worked, but I suspect the authentication/session handling is going to crash with that.
My hope is that I can exchange data with a PHP script when:
- the form loads (to check for PHP user session etc), and
- a "submit" button is clicked.
I covered the submit button part, and it works. Data is sent to, and returned from my PHP processing script to the JQuery front-end.
For handling the submit event, for some reason this code worked:
$(document).ready(function(){
as opposed to an onclick thing which didn't work.
This baffles me, as I read that document.ready is an event that occurs when the document has completed loading.
Q1: Could this have something to do with me using Jquery mobile sections (
Q2: What would be the correct JQuery event/trigger to use prior to loading, to control form "context"? (based on data from backend PHP).
Q3a: Is it a viable solution to rely on PHP sessions in such a case?
Q4: Also considering that I'd like to Phonegap it...will a PHP session be able to "see" the Jquery-based, phonegap-wrapped app like a client session just like if it was someone using a web-browser?
4b. When does a Phonegap app user session "end"? (When does the user have to log in again...).
I know similar questions have been raised several times, but please consider I'm a gullible idiot that knows too little to understand which case is similar enough to mine. There are some concepts here that I need to grasp before I can decide what to investigate and ask about :-)
Here's to tolerance and understanding! Cheers!
Eivind
You can store mobile id and users id in database with flag logged_in when they first logged in. Then again if user open that app, you can check the mobile id with the record in database whether user is exists or not and if exists then whats his/her status.
So the question is a little complicated, let me explain. My page code is running like this:
User enters query in the search field and clicks submit.
1.1 jQuery loads a new body to display progress data.
1.2 jQuery calls process.php via AJAX and supplies query as the argument.
1.3 jQuery starts setInterval periodic update to grab progress data, stored inside $_SESSION['prog'], and displays it.
When process.php finishes, jQuery stops periodic update, displays final information and calls AJAX to clear the $_SESSION['prog'] variable.
At the moment progress data is stored inside one variable, which is fine as far as different users are concerned (because of the different sessions), but if the same user were to make multiple requests at the same time, the $_SESSION['prog'] variable would be cross-overwritten.
So far I have thought of two possiblities to distinguish data for each request from the same user (same session)
Have jQuery generate some random string and send it together with query (and hope to avoid colission, although that would be unlikely)
Make 2 AJAX calls, first one requesting new_request_id, the second one sending query and new_request_id as parameters.
Have AJAX return something from PHP before is finishes(completes).
I need to connect each browser window (each request) with each running process, so I cannot send back new request ID after the request has been submitted, because I wont know which data to pick up with jQuery in the browser window. Btw, I will change $_SESSION['prog'] to $_SESSION[request_id] -> request_id is what I'm looking for.
It (request_id) could be last_insert_id(), because im creating new DB entries for each valid query, but I don't know how to get it back to each different user window.
I need advice here. Only just begun to code in PHP, AJAX and jQuery, don't really know much about sessions. How should I solve this problem?
Sorry for the lack of code, I will paste is at request.
You could add a unique ID to each request in addition to the session ID. eg. uniqid() in javascript/jquery?
You need to differentiate them somehow. For example use a unique ID autonumber field. MySQL has last_insert_id() which is very useful and handles concurrent requests correctly.
Avoid using Session variables in Ajax requests. Send them with GET (or POST) instead. Even if calling Session_start(); in the Ajax request and getting $_SESSION['prog'] from there, results can be unexpected.
I've been designing a site that is used to collect data, but the person I'm designing for wants some form of redundancy just in case the window is closed or the system shuts down. Is there any way to take data that's been collected and write it to a MYSQL database if the user is disconnected for a certain amount of time, or if they shut the browser window/shut the system down without submitting the data?
The web is stateless and disconnected - so all data will (or rather: should be) persisted between page requests.
I assume you have a web-page generated by PHP that contains a lengthy data-entry form, and you want to save the data in that form in the event the user closes their browser window - the solution is to use a client-script that polls the server with the current data in the form, or at the very least hooks on to the window close event.
Actual implementation is a task left up to the OP.
This can't be done just with a pure HTML page - if the user doesn't submit the form, your server doesn't know what they've typed.
However, you could put some Javascript on the page that made an AJAX call every few seconds (or every few key-stokes or clicks). The idea would be for the JavaScript to invisibly submit the whole form to a PHP page which saved it into a sort of "holding area".
If the user then submitted the form, the holding area could be cleared out, but if they never did, then the data in the holding area would show you where they got to.
The most common techniques to partially prevent this szenario is that web apps work with a heartbeat-function which fires via javascript in a constant interval and sends a request to the server, p.e. to show that the user is still logged on - or, in your case, maybe to submit data already typed into form fields, too.
Think of it as an ajax-powered auto-save-function!
You have to add some javascript to your code for this, but the commonly used javascript libraries, like jquery or mootools, are well documented and offer alot of examples how to do something like this.
I have a service running on a pc witch does some inserts in my (MySQL) database. What I want to do is everytime a new record is inserted in database to refresh automatically my webpage (I am using php). I read a relative post about updates
refresh the webpage on database update, but those updates were done "from" the webpage.
I also read another post
https://stackoverflow.com/questions/6460297/automatically-refresh-the-webpage-just-after-a-new-database-entry, didn't figure out how I can do this.
Any suggestions?
This is how you do it
Use JavaScript's settimeout() function to run an ajax request to your server at a set interval in which you send the id of the last record on the page. The use Javascripts window.location.reload() function to reset the page if the last record's id is different.
Why you don't want to refresh the page
This is bad user experience. You don't want the page refreshing out of no where. The best idea is to send the latest id on the current page to the server and check for any new ids. If there are new ideas send the records back via json and append them to the end of your results table.
This scenario is some complex but possible solution of your requirement!
In our scenario we have developed a sms-gateway and defining a trigger when ever any record is inserted we call a function that sends a sms to our gate way that behind that gateway we have developed our page. :)
In other way by defining timing ajax or many other ways where some what how our some resources are used, we have to compromise.
Ideally you want to trigger an update of data on the page via AJAX as opposed to a full page refresh. You can potentially accomplish this using web sockets. A popular server-side implementation is socket.io. Which uses the nodejs environment.
You could potentially write a MySQL UDF which executes in your trigger and signals nodejs to push more data (which may require writing a nodejs package as well). So, not trivial, but definitely doable :)
I am developing an online learning system (PHP, MySQL and Javascript). I would like to track what pages and how long each users spent on each page. Ideally, I would like to record this in a MySQL database. My question is 2 fold:
1. What kind of fields would I include in my db table to record multiple pages accessed?
2. Is this problem best approached by server side only or by using javascript ? e.g. server side: hidden form fields with a page id attached, page id is passed to db and recorded?or Javascript: record all actions in Javascript variables and somehow pass to db at end of session?
Really I am just looking for some high level guidance on an approach as opposed to code snippets.
GF
PHP isn't my normal language, but I would think about creating a module of code that can be called from the top of each of your scripts, that basically logs away "I served this page, with these form variables, at xxx ... ". To be more precise, I would record that in a table.
If you need to know when the user left your page, for a page on another site or perhaps shut down their browser for instance, then a purely server side solution isn't going to cut the mustard. In that event, you are going to have to start thinking about JavaScript, and intercepting events - such as the onUnload event...
Have a read here...
While I know of no solution that can track individual users out of the box (I'm sure there are some), I am pretty sure you could customize Piwik to do this. Piwik aims to be a self-hostable alternative to Google Analytics. It is open source and build on Zend Framework and MySql.
Piwik collects usage statistics through a JavaScript tracking code and a Webbug image for fallback. Basically, what you would need to do is pass the logged in user's user id to the tracking script and then write a plugin that knows how to handle this information.