We are implementing a chat application using Pubnub and in a short span of time, the number of channels for each user has reached into hundreds. In order to improve performance, I need the listChannels method to return channels in the most recently used first order rather alphabetical order which is of not much use to me.
I am hitting one roadblock after another and I very seriously considering ditching Pubnub altogether as it is creating more problems than solving them for me. Please help me with this.
Channel Groups were not implemented with what you had in mind. But you can keep a local list most active channels. Everytime the user publishes to a channel or receives a message or whatever your requirements are, just update this list.
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I have 2 closed-source application that must share the same data at some point. Both uses REST APIs.
An actual example are helpdesk tickets, they can be created on both applications and i need to update the data on one application when the user adds a new ticket/closes a ticket on the other application and vice versa.
Since is closed-source I can't really modify che code.
I was thinking I can create a third application that every 5 minutes or so, list both applications' tickets for differences on the precedent call, and if the data is different from the precedent call it updates the other application too.
Is there a better way of doing this?
With closed-source applications it's nearly impossible to get something out of them, unless they have some plugin-based setup that you can hook into.
The most efficient way in terms of costs would be to have the first application publish a message on a queue, or call a web-hook that you set, whenever the event is triggered. But as I mentioned, the application needs to support that.
So yeah, your solution is pretty much everything you can do for now, but keep in mind the challenges that you may encounter over time:
What if the results of both APIs are too large to be compared directly? Maybe you need to think about paging the results.
What if your app crashes and you loose the previous state? You need to somehow back it up in an external source
How often you should poll the API to make sure you're getting the updates you need, while keeping a good performance for the existing traffic?
I do have a helper application wich generates data which I need in my main application.
I'm searching for a way to push this data to the main app.
One way would be DistributedNotificationCenter.
The documentation says that notifications will be dropped if there are too many, but I cannot find a recommendation what the maximum suggested notifications are.
Currently I need to send an array with about 100 entries about 5-10 times a second.
If this is not a suggested way what would be a better one?
Thanks!
I am currently drafting a concept for a (mostly) HTML-based collaboration suite which I plan to implement using CQRS. This software will contain messages that can be sent to the user (which can either be read or unread, obviously) and other elements which shall be marked "new" if they were created after the last user login.
Hardly something new, but I am not quite sure how that would be correctly implemented using CQRS. As I understand it, Change of any kind should, without exception, only be possible via Commands. But creating commands for every single (new) element that is being accessed seems a bit too much, not to mention the overhead.
I don't know if I need it, but what would be the best way to implement a Last-Accessed Timestamp on elements. Basically the same problem like the above, with the difference that the change happens EVERY time the element is accessed, not only the first time for each user.
CQRS seems to be an awesome concept but it really needs more learning material. Can't wait till a book is released :)
Regards
[Edit] No one? Wouldn't have thought that this is such a complicated issue..
I assume you're using event-sourcing in which case once you allow your query-service/event-handlers to raise appropriate events then this becomes fairly easy to solve.
For your messages/elements; when handling the specific creation events of your elements either add to existing or create additional event-handlers, to store to a messages read-model with a status of new and appropriate information about the element.
As part of you're user login I don't see why you can't raise a user-logged-in event (from the security/query service depending on how your implementing authentication) to say the user has logged in. An event-handler could capture this and write the last-login timestamp to a specific user-last-login read-model.
In addition the user-logged-in event-handler would need to update all the new messages (for that user) to an unread status. Seeing as we're changing the status of the messages as the user logs in do you still need to store the last-login timestamp?
For your last-accessed timestamp, perhaps you could just work this into your query service as queries for your different elements complete. Raise a query-completed event with element id/type information.
I am willing to create a two-player quiz game, in real time. For this I need to track when users are on my quiz's page and when they leave it. Basically, I need some kind of lobby, where players gather and from where my script picks two random players who should face each other in the game.
As many players would switch from online to offline in a very short time, I prefer not to use the classic 'update player status to database and then retrieve at a given interval the list of online players'. Currently, I am toying with the idea of using Comet Push, and have studied a little bit PubNub.
The actual quiz game I believe it is pretty easy to solve: use of classic Comet publish() to send answers and subscribe() to check the other user's status. But the thing that bothers me is how do I get that specific list with online users?
I tried to publish() a user_id when a user goes to the lobby, but how do I notify all the other users when this user goes offline? How do I display in the lobby the total number of connected users together with their names?
It's the first time I face Comet and its logic isn't entirely clear to me.
Thank you for your help!
You might want to try out Pusher and our (I work for Pusher) presence functionality. The presence channels let you easily implement room/lobby-style functionality and should meet your criteria.
You get an initial list of users subscribed to the channel when you subscribed
You are informed whenever a user subscribes (enters) and unsubscribes (leaves) the channel (room/lobby)
This way you don't need to implement this functionality yourself. It's part of the solution Pusher provides.
You're probably a lot to be subscribers to various mailing list, some more updated than others.
What are your best practices to follow all information going by these lists?
What are the best clients you've used to managed that?
I'm sure I'm not the only one trying to get the best signal out of this noisy way of communication :)
I like gmail because of the way it groups messages by conversation so I can just page down through a thread.
Use a rule in GMail to slap a label on and archive all of them. Then they are easily sortable, searchable, and threaded.
I just use Thunderbird. For some lists, in flat mode, for others (the Lua mailing list), in threaded mode. Following is natural for mailing list, the messages are pushed to your client.
At first, I just received the messages and routed them to the right folder with some rules.
Now, I read them as newsgroups using Gmane, which also allow to catch up history (including mails which were sent before my subscription started and those which were sent during a temporary unsubscription).
Sometime, when a thread has no interest for me, I just right click on the first message and select Mark all messages of this thread as read.
Using KDE Ia m using Kontact for my mail and RSS feeds. That gives me a nice command center.