I'm designing a domotic network, which would basically consist in a main node that will act as a front-end where a web server will be hosted and a bunch of client nodes such as video entry-phone, irrigation control, alarm ...
The client nodes would register themselves on the front-end which would be, at that point, able of controlling their functionalities. I would like to use python for this project, so twisted and django would be the two main frameworks.
What's the smoothest way of having the clients interfaced with the front-end ?
The clients themselves could serve a webpage but I'm not really happy with this solution since I would like to have a single, main web server.
Could a light web server (twisted web server for instance) lazily turned on by the frontend if the user wants to control a given client be a solution here ?
What about defining some "public" amp.Command classes which could be adapted by the server to paint the client's specific web interface ? (some client business would need to be on server side that way)
Any advice is welcome.
Related
I've build before server-client programs (both sides where build in python by far).
Recently I started building app using swift and my goal is to add a backend to my apps using python (My app is a chat app)
I searched in the Internet a tutorials to do so, and I only saw two options to communicate between server side and mobile application, the first one is to create an API (REST) (request - response) - I can't use this solution because I want a real-time chat.
And the second option was web-sockets (socket.IO).
SO, my question is why not use the simple socket technology (like I used to use when it was only python server side to python client side -> import sockets) - no sockets over web
following Features You will get if you are using Socket.io or socketcluster.io (which is developed on the top of Socket IO)
scalability :- It will scale horizontally adding more nodes (scale-out) & Linearly(scale-up)
Reduces Payload size as message payload is compressed
Authorisation via middle ware functions
Reconnects Automatically if Connection drops
If You want to use your own implementation then you have to take care of the above features/Solutions to problems which arises when User-base is increases.
My understanding is Socket.IO isn't necessary anymore because all browsers worthwhile constantly keep each other in check. Socket.IO was for when browsers and servers didn't support the same technology. These days, everything is pretty much supported and Socket is perfectly safe to stick to without the use of Socket.IO. More of a breakdown here - https://codeburst.io/why-you-don-t-need-socket-io-6848f1c871cd
I'm building a turn-based game and I'm hoping to implement client-server style networking. I really just need to send the position of a couple of objects and some other easily encodable data. I'm pretty new to networking, although I've coded some basic stuff in socket and twisted. Now, though, I need to be able to send the data to a computer that isn't on my local network, and I can't do port forwarding since I don't have admin access to the router and I'm also not totally sure that would do the trick anyways since I've never done it. So, I was thinking of running some Flask or Bottle or Django, etc. code off PythonAnywhere. The clients would then send data to the server code on PythonAnywhere, and when the turn passed, the other client would just go look up the information it needed on the server. I guess then the server would act as just a data bank with some simple getter and setter methods. My question is how can this be implemented? Can my Socket code on my client program talk to my Flask code on PythonAnywhere?
Yes, client code can talk to your project at PythonAnywhere, as you will be given a unique project url like http://yourblogname.pythonanywhere.com/. Your server will listen the 80 port at that url.
It depends what sort of connection your clients need to make to the server. PythonAnywhere supports WSGI, which means "normal" HTTP request/response interactions -- GET, POST, etc. That works well for "traditional" web pages or web apps.
If your client side needs dynamic, two-way connections using non-HTTP protocols, using raw sockets, or even websockets, PythonAnyhwere doesn't support that at present.
The scenario is
I have multiple local computers running a python application. These are on separate networks waiting for data to be sent to them from a web server. These computers are on networks without a static IP and generally behind firewall and proxy.
On the other hand I have web server which gets updates from the user through a form and send the update to the correct local computer.
Question
What options do I have to enable this. Currently I am sending csv files over ftp to achieve this but this is not real time.
The application is built on python and using django for the web part.
Appreciate your help
Use a REST API. Then you can post information to your Django app over HTTP, using an authentication key if necessary.
http://www.django-rest-framework.org/ should help you get started quickly
Sounds like you need a message queue.
You would run a separate broker server which is sent tasks by your web app. This could be on the same machine. On your two local machines you would run queue workers which connect to the broker to receive tasks (so no inbound connection required), then notify the broker in real time when they are complete.
Examples are RabbitMQ and Oracle Tuxedo. What you choose will depend on your platform & software.
I am creating a web app which needs to continuously poll my django web server to get an update. Is there a way avoid this polling? Like server can send push messages on update or the client registers a callback for an event and server triggers the callback whenever something changes.
I know there are signaling frameworks in ASP.net etc. but I want something which can work with Django.
Thanks
Fundamentally web sockets, part of HTML5, were design for this purpose, ie bi-directional communication between clients and servers through the http protocol, while its being highly talked about few application servers have implemented and even fewer http servers have actually even began supporting it.
While there are some packages:
django-websocket
django-socketio
that have enabled it in django, they don't do anything about your http server, very rarely if ever do you use django standalone, this is because django isn't very efficient for distributing static content such as images or any other static files, as well as distribute work load, we rely on things like nginx, apache and such things for this. unfortunately they don't support web sockets, yet, as such they tend to break the communication between the client and the application server even if its initiated in the first place, depending on implementation.
From my own personal experience nginx would break the communication after 60 seconds since this was the default allotted time for anything open.
As far as I know node.js maybe the best server, currently, for working with web sockets.
Depending on what you are tying to achieve and If regular polling seems in efficient you can try long-polling, basically the connection is held open, until theres new data to be pushed back unto the client vs regular polling, which is done at some interval, note that you may have to configure your http server not to terminate pro-long open connections and run django multithreaded, since each connection will use an instance.
Is it possible to send data from app engine server to another,external server with httpd service? I don't care if the payload will be 1 bit, I just need to make this happen.
I checked all over the place and found this:
"
Can't Open Sockets To Arbitrary Ports
Given that Google App Engine is a constrained runtime environment, it has an understandable limitation of preventing you from opening sockets on arbitrary ports. This restriction is necessary for security and scalability and Google can only be expected to enable these scenarios by providing their own wrapper libraries for each desired scenario. However, this leads to restrictions on important scenarios. For example, if your application wants to incorporate email and connect to an IMAP server, then you have no ability to do this on GAE.
While Google does plan to eventually add additional services to their capabilities, there is no plan for providing a general capability for opening sockets.
"
in here
and from here, I have a new question: Is it possible to keep a connection from my linux service to app engine(the other way around) ? if my linux was a android device, it would be possible. can my server pretend to be android device that will listen to events from the server? I implemented push notification on app engine and i have another server for push for iPhones, when the app engine sends to all, i need the linux to know about it and to send to all iphones as well.
thanx!
So you have two questions:
Is it possible to send data from app engine server to another,external
server with httpd service?
Yes, you can have make outgoing http connections from your GAE app (link).
Is it possible to keep a connection from my linux service to app
engine(the other way around) ?
You can if you use Channel API to stream events to your linux. If I remember correctly you'll just have to request a new connection token every hour.