I am using .net4. I have created a web app which is doing polling every 30sec.
I have a wcf service which writes to database the desired data which comming from android clients.
The polling that the web site do every 30sec is based upon data from android.
As optimization instead of polling i was thinking something like "google cloud messaging". I mead that the ideal implementation should be :
Android push data to my db.
Instantly when data inserted ok to my db, send "something" in order website ask database
for data
My app is finished, is working with out problems so far.
The question:
Is there any way to implement the ideal implementation above?
I have tried singalr and comet. But i have not find something that i could implement in my situation.
I will appreciate any help.
Finally i have found solution to my problem. I follow this example.
I used SingalR (which is great lib).
Related
I have an assignment to display, into a Hololens 2 (Unity Project), two video feeds (stereo camera) coming from a LattéPanda. For now, I successfully manage to do the demo from the Mixed-Reality WebRTC project locally, but I have some difficulties with the remote streaming.
The problem is how to make my application based on the Mixed-Reality C# Core 3.1 connect to my NodeDSS signaler since the demo uses a NamedPipeSignaler class that can't reach out to localhost? So I look up the classes they provided in the hope of getting the required method to implement, also with the interaction it needs to do with the PeerConnection object. It started to be a little complicated, so we look up other solutions.
One of the solutions we found was the OWT-Server (Open WebRTC Toolkit) which seems to give us already dockerize application to videocast on its own. However, the documentation doesn't specify much other than we need to link the docker image to an "application", which is not clear what it is supposed to do. We don't have any way to specify the STUN/TURN server, nor the signaler IP address for that matter.
So my goal at this point is very simple: just make one feed appear into my Unity project. The LattéPanda's only objective right now is to cast the video without caring much for any interaction (for now): it won't receive or even need to listen to any feed coming back ever, and for now, there is no need to interact with other tools. I've been searching for about 2 weeks now and my GoogleFu is not that good apparently. Is there any tool that could achieve this?
A little disclaimer: I do believe I still lack an understanding of the Signaling process. It seems that WebRTC does not enforce any standard in that regard. What I understand is the communication protocol (WebSocket, HTTP/2) is not standardized, only the messaging is (what message needs to be sent/handle).
EDIT
To be clear, the LattéPanda currently runs a console application written in C# Core 3.1. The reason is, like I said, that the LattéPanda should not display any of its feed to a monitor connected to it, nor received/handle any feed from outside. We can see it like a surveillance camera that outputs its feed through WebRTC and doesn't need to receive any feed.
Hi I have started a project which connects to a database and creates/logs in a user at the moment i have a LAN messenger that works very well, and a FTP chat which is not exactly what i was hoping for.
my idea now is to create two tables in the database message 1 and message 2 both of which display the user who is sending and the message sent. and the program uses threading to connect and download the messages.
My question is, is there a better way of completing this task (if so could you send a link or two this way? or express your opinion).
and or any problems you guys/girls think i would run into. Cheers :D
If you require to see some code just ask and i'll edit the post thanks
Although its easy on paper to do a chat application that uses a 'DB' as a backend/comms layer .. its not really the best approach. It will work... but with load, it may not be a very good approach.
Most chat clients uses a peer to peer connection, or even client server with the coding and implementation of a server that handles what happens with messages going/destined where ever.
If you really want to get low down and dirty, google for 'TCP chat application' examples. If you want to operate a bit higher (not handle the really gritty low down mechanics), then look for some 'wcf chat' examples.
I was always wondering if it's possible to create a block of code (probably php code) that will execute when a certain change is being committed to the database.
For instance, chat application. When a user sends a message, it will add a message to a table, then I would like to force all of the other users to an AJAX request to read this new value (rather than sending AJAX request every 100ms to check if there is a new message)
I remember something that involved node.js and some other type of DB rather than mysql. If this is the only solution, can it work along with a normal mysql database?
Thanks in advance!
Yes, MySQL supports triggers, but they are pretty much limited to do other data operations. So you'd still have to get some notification sent to your javascript client
A better way of doing client notifications with with websocket or comet, allowing the server to push notifications from a message-queue.
You didn't give much detail about your programming environment, so I'll leave it to you to follow the tag links I gave above, and research the appropriate tools and frameworks for using these general methods.
Re your comment:
For PHP, here's an example "push" chat application:
http://www.aljtmedia.com/blog/websockets-for-php-ratchet-push-chat-application/
Here's an primer on using message queues in general:
http://blog.thecodepath.com/2013/01/06/asynchronous-processing-in-web-applications-part-2-developers-need-to-understand-message-queues/
And here are tutorials for RabbitMQ (one simple option among many MQ solutions usable by PHP), including PHP examples: https://www.rabbitmq.com/getstarted.html
I'm making a mobile client for a web site now. And information exchange between my app and server is in JSON (searching users and data on server,sending messages, conversation threading, etc.) But all these features work too slow. I click on the button "send" and then wait for some second before the message will be sent, the same thing with searching, authorization, etc. So I have such a questions:
1. Why it's such a performance overhead?
2. Can it be troubles with the server side or it's JSON parser troubles or may be something else?
3. How can i fix/optimize this? All solutions, advices etc. will be helpful!
I would use Xcode to debug the app to see whether the majority of time is spent loading the data from the server or parsing the JSON once the data is received.
If it is the first, try loading the data from a PC over the same wireless connection and see if it is slow on that too. If so, clearly your server side code needs optimising.
If it is the second and the parsing is slow, you may want to look into using JSONKit instead of the native JSON parser as testing shows it is faster. You may also want to review the structure of your JSON.
One thing I have noticed however is that connections are slower on my iPad than on other machines. I've noticed this when comparing apps I've developed in the simulator to on the device on the same network and when conducting speedtests. As for why this happens, I am not sure - some form of additional overhead in iOS perhaps.
I can save you some time - it has nothing to do with JSON. It has to do with how the your app handles requests in general. It obviously needs optimization on the server.
EDIT:
I suppose it could also be that you might be experiencing high-latency on your phone, but again, that has nothing to do with your app.
Debug it using a regular browser and chrome dev tools (in the network tab) - you'll see that the requests take long even on a desktop at which point you'll have to start fishing around in the server-side code to see what's making it go slow (hint: unoptimized database queries are a big bottleneck....but then again, so is crappy hardware).
Sorry that I couldn't be of more help, but without seeing the entire setup of the server and the code that's going slow (not the client requests, but the server code), that's the best I can do.
Best of luck.
I'm playing around with windows azure and I would like to build a clouded server application that receives messages from many different clients, such as mobile and desktop.
I would like to build the client so that they work while in "offline-mode", i.e. I would like the client to build up a local queue of messages that are sent to the azure server as soon as they get online.
Can I accomplish this using wcf and/or azure queing mechanism, so that I don't have to worry about whether the client is online or offline when I write the code?
You won't need queuing in the cloud to accomplish this. For the client app to be "offline enabled" you need to do queuing on the client. For this there are many options, a local database, xml files, etc. Whenever the app senses network availability you can upload your queue to Azure. And yes, you can use WCF for that.
For the client queue/sync stuff you could take a look at the Sync Framework.
I haven't found a great need for the queue so far. Maybe it's just that I'm not seeing it in my app view. Could also be that the data you can store in the queue is minimal. You basically store short text strings (like record ids), and then you have to do something with the ID when you pull it from the queue, such as look it up, delete it, whatever.
In my app, I didn't use the queue at all, just as Peter suggests. I wrote directly to table storage (accessed via it's REST interface using StorageClient) from the client. If you want to look at a concrete example, take a look at http://www.netalerts.mobi/traffic. Like you, I wanted to learn Azure so I built a small web site.
There's a worker_role that wakes up every 60 seconds. Using one thread, it retrieves any new data from it's source (screen scraping a web page). New entries are stored directly in table storage (no need for a queue). Another thread deletes entries in table storage that are older than a specified threshold (there's no issue with running multiple threads against table storage). And then I'm working on the third thread which is designed to send notifications to handheld devices.
The app itself is a web_role, obviously.