I've build a little device based on the raspberry pi. Now I want to configure it using my web server. The idea is that I enter all the details on my django web page and then the device just pulls that off the server.
But there are two problems I'm not sure how to solve:
I have multiple devices for multiple users so some kind of Login must be provided.
The device also sends pictures from time to time. Right now it's using FTP with a general login, but I want to personalize that too for every device. The uploads will need a resume function so http is out!
So the basic question is: Should I get started with sockets or is there a better and safer way to do it? Maybe there is some kind of open source library that's been tested a lot?
Instead of hand coding sockets, I would suggest using HTTP with BASIC authentication to communicate between the device and the web server. You can uniquely assign an id/pwd to each device, and BASIC authentication is well supported by all web servers and client side libraries.
There are some security concerns with BASIC authentication even if you use HTTPS, but it maybe acceptable in your particular case here.
Maybe you could use SSH, with Fabric for instance. Here an example.
Related
I have a bit of an open ended questions for you all. I wish to create a simple chat-room such as this example here: https://www.geeksforgeeks.org/simple-chat-room-using-python/ but I am lost as how to do it over the internet rather than just local network.
Any pointers/help would be appricated!
Thanks :)
There are multiple ways about this. You can either:
Run locally and expose your Python chat system to the internet.
Run your Python chat system in some online server provider (Heroku, AWS, etc.).
The first method requires you to do some port-forwarding on your local network, essentially mapping your 127.0.0.1:8081 local server to your public IP (so you would connect via the internet as myip:8081). This method, however, comes with its limitations; when you turn off your computer you are also effectively turning off your server to the rest of the internet. The second method will ensure the server stays on at all times, and is likely what you are looking for. Heroku is a great starting point as they provide a free tier that you can test everything out.
I'm struggling to design an efficient way to exchange information between processes in my LAN.
Till now, I've been working with one single RPi, and I had a bunch of python scripts running as services. The services communicated using sockets (multprocessing.connection Client and Listener), and it was kind of ok.
I recently installed another RPi with some further services, and I realized that as the number of services grows, the problem scales pretty badly. In general, I don't need all the services to communicate with any other, but I'm looking for an elegant solution to enable me to scale quickly in case I need to add other services.
So essentially I though I first need a map of where each service is, like
Service 1 -> RPi 1
Service 2 -> RPi 2
...
The first approach I came up with was the following:
I thought I could add an additional "gateway" service so that any application running in RPx would send its data/request to the gateway, and the gateway would then forward it to the proper service or the gateway running on the other device.
Later I also realized that I could actually just give the map to each service and let all the services manage their own connection. This would mean to open many listeners to the external address, though, and I'm not sure it's the best option.
Do you have any suggestions? I'm also interested in exploring different options to implement the actual connection, might the Client / Listener one not be efficient.
Thank you for your help. I'm learning so much with this project!
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 working out how to build a python app to do image processing. A client (not a web browser) sends an image and some text data to the server and the server's response is based on the received image.
One method is to use a web server + WSGI module and have clients make a HTTP POST request (using multipart/form-data). The http server then 'works out' the uploaded image and other data that the program can use.
Another method is to create a protocol that only sends the needed data and is handled within the application. The application would be doing everything (listening on the port, etc).
Is one of these a stand-out 'best' way (if yes, which one?), or is it more up to preference (or is there another way which is better)?
I believe it's more up to your needs, the size of the images, and your general knowledge of network programming.
In terms of simplicity, posting an image to the webserver using WSGI would be fairly simple, and you wouldn't have to worry about handling connections, sockets, error handling due to busy network ports, etc.
Another argument in favor of this approach is that you can easily reuse this "feature" if you already have it working on a webserver, say, by including a browser client. It might not be one of your needs now, but the door is left open.
This would be my choice.
Also, in Python you have a huge plethora of web frameworks to choose from, from the likes of Django, which is probably a huge overkill for your needs, to something alot simpler, like http://flask.pocoo.org/ which might just suit your needs and is really simple to set up.
In my opinion HTTP is an ideal protocol for sending files or large data, and its very common use, easy to suit any situation. If you use a self-created protocol, you may find it hard to transform when you get other client needs, like a web API.
Maybe the discussions about HTTP's lack of instantaneity and agility make you hesitate about choosing HTTP, but that mostly something about instant messaging and server push, there are better protocols. But when it comes to stability and flexiblity, HTTP is always a good choice.