I am planning to add in the message carbon function(when a user is logged into multiple device and send a message or/receive a message, it will sync between all devices) for a chat server, i am running on Ejabberd and using strophe.js...
I am wondering if there are plugin written for Ejabberd that i can install and also for strophe.js???
I looked over https://github.com/processone/ejabberd-contrib and the github for strophe.js
None of them seem to have plugins for message carbon. Wondering if anyone has this implemented before??
I have read that if it doesnt, i should treat it as a groupchat??? I am not sure why that would work??? And not exactly sure if thats good for the resources, and what if it scales up, would that have impact on the overall structure.
If it is treated as a group chat, then i assume each resource/session would be treated as a different user? Then when a message is sent into that group, all of those other session/users are updated, so even there are 2 users??
ejabberd supports message carbons as default in latest version.
This feature is unrelated to groupchat and cannot and should not be treated similarly.
If you read XEP-0280 Message Carbons you should see that sending a packet similar to the following is enough to enable it:
<iq id='enable1' type='set'>
<enable xmlns='urn:xmpp:carbons:2'/>
</iq>
You may find also valuable information in XMPP Academy video #2 at 27m30s.
I'm doing a little project for my class and I'm just a beginner, so please forgive me if I mix up some of my terminology.
Basically, I'm creating an interactive journey planner for my city's public transit system. Unfortunately, they haven't made all the data I need publicly available. So instead of putting all my time into gathering the data for personal use, I've opted to do some screen scraping - letting their servers calculate the journey info from a START and STOP variable and then displaying the selected info on my page.
So is it possible to fill out a form's fields remotely, and then scrape the data on the page that subsequently loads? And if so, what would be the quickest, most convenient way? This happens to be a case where the data can't be manipulated via the URL, so it has to access the data by filling out the form first.
The website in question:
http://jp.translink.com.au/travel-information/journey-planner
Here is what you can do:
1.) Send a POST Request to the journey-planner with some data like that (be aware that CORS might jump in, then you could use cURL via PHP or whatsoever):
Start:Wickham Tce, Spring Hill
End:Upper Edward St, Spring Hill
SearchDate:10/05/2013 12:00:00 AM
TimeSearchMode:LeaveAfter
SearchHour:7
SearchMinute:40
TimeMeridiem:AM
TransportModes:Bus
TransportModes:Train
TransportModes:Ferry
MaximumWalkingDistance:1500
WalkingSpeed:Normal
ServiceTypes:Regular
ServiceTypes:Express
ServiceTypes:NightLink
FareTypes:Standard
FareTypes:Prepaid
FareTypes:Free
2.) You will get a new response location. This seems to be a REST link. Important for you is the id at the end. You will have to call that page and parse the HTML and look for a div with the HTML-id option-summaries, where you will find more information within the divs travel-option-1 to travel-option-n. You have to look at it carefully in order to find out which information is stored whee and how you will be able to use it.
In order to find such things you should learn how to use Firebug or Chrome's development tools.
This is one way to solve your problem. Probably not the best but still better than "screen-scraping" anything. But it will ask you for a lot of skills and effort. Furthermore if the data provider is going to change just a bit your solution will not work anymore. Additionally they might prevent your access by CORS or anything else (blocking your IP etc.)
I'm looking for a way to create a simple HTML table that can be updated in real-time upon a database change event; specifically a new record added.
In other words, think of it like an executive dashboard. If a sale is made and a new line is added in a database (MySQL in my case) then the web page should "refresh" the table with the new line.
I have seen some information on the new using EVENT GATEWAY but all of the examples use Coldfusion as the "pusher" and not the "consumer". I would like to have Coldfusion both update / push an event to the gateway and also consume the response.
If this can be done using a combination of AJAX and CF please let me know!
I'm really just looking to understand where to get started with real-time updating.
Thank you in advance!!
EDIT / Explanation of selected answer:
I ended up going with #bpeterson76's answer because at the moment it was easiest to implement on a small scale. I really like his Datatables suggestion, and that's what I am using to update in close to real time.
As my site gets larger though (hopefully), I'm not sure if this will be a scalable solution as every user will be hitting a "listener" page and then subsequently querying my DB. My query is relatively simple, but I'm still worried about performance in the future.
In my opinion though, as HTML5 starts to become the web standard, the Web Sockets method suggested by #iKnowKungFoo is most likely the best approach. Comet with long polling is also a great idea, but it's a little cumbersome to implement / also seems to have some scaling issues.
So, let's hope web users start to adopt more modern browsers that support HTML5, because Web Sockets is a relatively easy and scalable way to get close to real time.
If you feel that I made the wrong decision please leave a comment.
Finally, here is some source code for it all:
Javascript:
note, this is a very simple implementation. It's only looking to see if the number of records in the current datatable has changed and if so update the table and throw an alert. The production code is much longer and more involved. This is just showing a simple way of getting a close to real-time update.
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.js"></script>
<script type="text/javascript" charset="utf-8">
var originalNumberOfRecsInDatatable = 0;
var oTable;
var setChecker = setInterval(checkIfNewRecordHasBeenAdded,5000); //5 second intervals
function checkIfNewRecordHasBeenAdded() {
//json object to post to CFM page
var postData = {
numberOfRecords: originalNumberOfRecsInDatatable
};
var ajaxResponse = $.ajax({
type: "post",
url: "./tabs/checkIfNewItemIsAvailable.cfm",
contentType: "application/json",
data: JSON.stringify( postData )
})
// When the response comes back, if update is available
//then re-draw the datatable and throw an alert to the user
ajaxResponse.then(
function( apiResponse ){
var obj = jQuery.parseJSON(apiResponse);
if (obj.isUpdateAvail == "Yes")
{
oTable = $('#MY_DATATABLE_ID').dataTable();
oTable.fnDraw(false);
originalNumberOfRecsInDatatable = obj.recordcount;
alert('A new line has been added!');
}
}
);
}
</script>
Coldfusion:
<cfset requestBody = toString( getHttpRequestData().content ) />
<!--- Double-check to make sure it's a JSON value. --->
<cfif isJSON( requestBody )>
<cfset deserializedResult = deserializeJSON( requestBody )>
<cfset numberOFRecords = #deserializedResult.originalNumberOfRecsInDatatable#>
<cfquery name="qCount" datasource="#Application.DBdsn#" username="#Application.DBusername#" password="#Application.DBpw#">
SELECT COUNT(ID) as total
FROM myTable
</cfquery>
<cfif #qCount.total# neq #variables.originalNumberOfRecsInDatatable#>
{"isUpdateAvail": "Yes", "recordcount": <cfoutput>#qCount.total#</cfoutput>}
<cfelse>
{"isUpdateAvail": "No"}
</cfif>
</cfif>
This isn't too difficult. The simple way would be to add via .append:
$( '#table > tbody:last').append('<tr id="id"><td>stuff</td></tr>');
Adding elements real-time isn't entirely possible. You'd have to run an Ajax query that updates in a loop to "catch" the change. So, not totally real-time, but very, very close to it. Your user really wouldn't notice the difference, though your server's load might.
But if you're going to get more involved, I'd suggest looking at DataTables. It gives you quite a few new features, including sorting, paging, filtering, limiting, searching, and ajax loading. From there, you could either add an element via ajax and refresh the table view, or simply append on via its API. I've been using DataTables in my app for some time now and they've been consistently cited as the number 1 feature that makes the immense amount of data usable.
--Edit --
Because it isn't obvious, to update the DataTable you call set your Datatables call to a variable:
var oTable = $('#selector').dataTable();
Then run this to do the update:
oTable.fnDraw(false);
UPDATE -- 5 years later, Feb 2016:
This is much more possible today than it was in 2011. New Javascript frameworks such as Backbone.js can connect directly to the database and trigger changes on UI elements including tables on change, update, or delete of data....it's one of these framework's primary benefits. Additionally, UI's can be fed real-time updates via socket connections to a web service, which can also then be caught and acted upon. While the technique described here still works, there are far more "live" ways of doing things today.
You can use SSE (Server Sent Events) a feature in HTML5.
Server-Sent Events (SSE) is a standard describing how servers can initiate data transmission towards clients once an initial client connection has been established. They are commonly used to send message updates or continuous data streams to a browser client and designed to enhance native, cross-browser streaming through a JavaScript API called EventSource, through which a client requests a particular URL in order to receive an event stream.
heres a simple example
http://www.w3schools.com/html/html5_serversentevents.asp
In MS SQL, you can attach a trigger to a table insert/delete/update event that can fire a stored proc to invoke a web service. If the web service is CF-based, you can, in turn, invoke a messaging service using event gateways. Anything listening to the gateway can be notified to refresh its contents. That said, you'd have to see if MySQL supports triggers and accessing web services via stored procedures. You'd also have to have some sort of component in your web app that's listening to the messaging gateway. It's easy to do in Adobe Flex applications, but I'm not sure if there are comparable components accessible in JavaScript.
While this answer does not come close to directly addressing your question, perhaps it will give you some ideas as to how to solve the problem using db triggers and CF messaging gateways.
M. McConnell
With "current" technologies, I think long polling with Ajax is your only choice. However, if you can use HTML5, you should take a look at WebSockets which gives you the functionality you want.
http://net.tutsplus.com/tutorials/javascript-ajax/start-using-html5-websockets-today/
WebSockets is a technique for two-way communication over one (TCP) socket, a type of PUSH technology. At the moment, it’s still being standardized by the W3C; however, the latest versions of Chrome and Safari have support for WebSockets.
http://html5demos.com/web-socket
Check out AJAX long polling.
Place to start Comet
No, you can't have any db code execute server side code. But you could write a service to poll the db periodically to see if a new record has been added then notify the code you have that needs pseudo real-time updates.
The browser can receive real-time updates via BOSH connection to Jabber/XMPP server. All bits and pieces can be found in this book http://professionalxmpp.com/ which I highly recommend. If you can anyhow send XMPP message upon record addition in your DB, then it is relatively easy to build the dashboard you want. You need strophe.js, Jabber/XMPP server (e.g. ejabberd), http server for proxying http-bind requests. All the details can be found in the book. A must read which I strongly believe will solve your problem.
The way I would achieve the notification is after the database update has been successfully committed I would publish an event that would tell any listening systems or even web pages that the change has occurred. I've detailed one way of doing this using an e-commerce solution in a recent blog post. The blog post shows how to trigger the event in ASP.NET but the same thing can easily be done in any other language since ultimately the trigger is performed via a REST API call.
The solution in this blog post uses Pusher but there's not reason why you couldn't install your own real-time server or use a Message Queue to communication between your app and the realtime server, which would then push the notification to the web page or client application.
What would be a good starting point for me to learn about creating an email server?
Basically, what I want to do is have a server (such as foo.com) recieving mail for me so if I send an email to (blah#foo.com) it will dump the contents of the email into /mail/blah/subject and then send it off to my REAL email account.
I'm looking to do this as a programming exercise, so links to RFCs, etc. would be nice. Reinventing the wheel is a good way to learn about wheels.
EDIT: Feel free to retag this appropriately.
Edit: I provided some headings and divided RFCs by topic. I hope it's more accessible now. It's quite a list, and I wish I could format it any better, but unfortunately, that's about it.
Since you mentioned you don't really know what you need, let me clarify:
If you only want to implement a simple "proxy" server that sits in between your MUA (email client) and "real" server, you can probably get away with only implementing basic SMTP functionality. This will allow you to send messages, i.e. to submit messages to an MTA.
POP3 is for email clients to pull messages off of your server, while IMAP is an alternative to POP3 with a somewhat different feature set, mainly providing an on- or offline mode which can be thought of like managing remote folders (i.e. mailboxes).
MIME specifies the format of the contents of e-mail messages in presence of multi-part messages, attachments etc.
Internet Message format (also defines e-mail address format)
http://www.faqs.org/rfcs/rfc822.html
http://www.faqs.org/rfcs/rfc2822.html
SMTP:
http://www.faqs.org/rfcs/rfc821.html
Update to SMTP/RF821:
http://www.faqs.org/rfcs/rfc5321.html
SMTP-AUTH:
http://www.faqs.org/rfcs/rfc2554.html
Message submission (i.e. for the application to be acting as a MUA):
http://www.faqs.org/rfcs/rfc2476.html
IMAPv4:
http://www.faqs.org/rfcs/rfc1730.html
IMAPv4rev1:
http://www.faqs.org/rfcs/rfc2060.html
POP3:
http://www.faqs.org/rfcs/rfc1081.html
http://www.faqs.org/rfcs/rfc1939.html
http://www.faqs.org/rfcs/rfc1957.html
POP3 extensions:
http://www.faqs.org/rfcs/rfc2449.html
Authorization for POP/IMAP:
http://www.faqs.org/rfcs/rfc2195.html
TLS for POP3 and IMAP:
http://www.faqs.org/rfcs/rfc2595.html
AUTH-RESP-CODE for POP3:
http://www.faqs.org/rfcs/rfc3206.html
POP3 simple authentification:
http://www.faqs.org/rfcs/rfc5034.html
MIME, which is composed of 5 RFCs:
http://www.faqs.org/rfcs/rfc2045.html
http://www.faqs.org/rfcs/rfc2046.html
http://www.faqs.org/rfcs/rfc2047.html
http://www.faqs.org/rfcs/rfc4288.html
http://www.faqs.org/rfcs/rfc4289.html
http://www.faqs.org/rfcs/rfc2049.html
Has anyone tried accessing bungie.net reach stats api (statistics from Halo Matchmaking)?
As described here http://www.bungie.net/fanclub/statsapi/Group/Resources/Article.aspx?cid=545064
I can't seem to get any data returned, for example if i use this (with correct API key and gamertag values of course) ignore the first 2 asterisks ...
**http://www.bungie.net/api/reach/reachapijson.svc/player/details/byplaylist/MyIdentifierAPIkey/Gamertag
I don't receive a response - but no errors either, am i doing something wrong?
looking to use this for a Titanium (appcelerator) app eventually.
Any help or advice welcome, thanks in advance.
Unfortunately the API is not yet live to the public. I asked in a Private Message. They didn't say when it would be live.
In the Docs that Achronos posted, he put spaces in the URL's, I'm not sure if those are supposed to be there or not, so I tried it with the spaces and I got a 403 Forbidden error page. When I remove all the spaces, I get an error page that says:
Request Error
The server encountered an error processing the request. See server logs for more details.
I kinda can't check the server logs though... Bungie did say they were having some issues with the site though, so this might be a biproduct of that. I want them to get it working soon though, I wanna see just what it can do!