So I'm doing this python basics course and my final project is to create a card game. At the bottom of the instructions I get this
For extra credit, allow 2 players to play on two different computers that are on the same network. Two people should be able to start identical versions of your program, and enter the internal IP address of the user on the network who they want to play against. The two applications should communicate with each other, across the network using simple HTTP requests. Try this library to send requests:
http://docs.python-requests.org/en/master/
http://docs.python-requests.org/en/master/user/quickstart/
And try Flask to receive them:
http://flask.pocoo.org/
The 2-player game should only start if one person has challenged the other (by entering their internal IP address), and the 2nd person has accepted the challenge. The exact flow of the challenge mechanism is up to you.
I already investigated how flask works and kind of understand how python-requests works too. I just can't figure out how to make those two work together. If somebody could explain what should I do or tell me what to watch or read I would really appreciate it.
it would be nice to see how far you've come before answer (as hmm suggested you in a comment), but i can tell you something theorical about this.
What you are talking about is a client-server application, where server need to elaborate the result of clients actions.
What i can suggest is to learn about REST API, that you can use to let client and server to communicate in a easy way. Your clients will send http requests to server exposed APIs.
From what you wrote, you have a basically constraints that should be respected during client and server communication, here reasumed:
Someone search for your ip and send you a challenge request
You have received a challenge that you refuse or accept; only if you accept the challenge you can start the game
As you can see from the project specifications the entire challenge mechanism is up to you, so you can decide the best for you.
I would begin start thinking to a possible protocol that make use of REST API to start initial communication between client and server and let you define a basic challenge mechanism.
Enjoy programming :).
Related
Premise: I am a beginner in search for an easy way to send bug reports from users over sea.
I've made a script for some friends that are living on the other side of the sea (US - EUROPE)... I will like to gather automatic bug reports whenever they happen. So my first idea was to send myself an email with the smtplib module. It works fine when testing home, but as soon as the sender "sends", my email provider (gmail) blocks the connection because of course, its from an "unknown device". I've already enabled "Allow less secure apps" as someone suggested but with no avail.
What I am searching its a simple way of dealing with this.
Yes I could make the script to ignore the error if the email its not being sent, and then go into my google account and enable those devices so at least it will work from the second run..
But it doesn't seem what a programmer would do in this case. I am learning so a solution withing the language is what I am after.
A different provider that has no restriction its also a good start but I tried Yahoo, Live, Yandex but I couldn't make them work. Are there any?
So my question is: how others do? what is the best solution for some one like me?
I've read about sentry or other error/bug tracking but its obviously way too much for want I need
You should certainly not incorporate e.g. Gmail credentials in the code that is remotely executed on devices you do not control, given I understand correctly the Gmail less secure device issue happens as every "user" is running this code and using your credentials. This holds true for any other provider.
Now this won't exactly be simple but one way to go about it would be to create a server side API endpoint that can accept HTTP(s) or any other protocol requests that then will authenticate in a little more secure way on the server side with Gmail.
The concept for emails is:
Bug > Python Script > API call > Email
This could be implemented using Python on the API side (Flask e.g.) using an AWS Lambda Function with Amazon API Gateway, but again that is something to get through and understand by itself which will take a good chunk of time.
You need to touch a lot of concepts, like auth tokens to make this really secure.
Could you elaborate a little on where the code needs to run and if you are willing to try AWS or any other cloud provider, or would have access to an internet connected server ? This makes it easier to provide you with a full example on the solution in a hackish way while I would highlight the problems you could face on the security side.
I understand that this is not the way to go but as for my needs and my level of experience it works for me!
Yandex allows you to send email from different ip so Yandex is the way to go. What I was doing wrong in the first place was to use the wrong port (587 instead of 465)
Mornink!
I need to design, write and implement wide system consisting of multiple unix servers performing different roles and running different services. The system must be bullet proof, robust and fast. Yeah, I know. ;) Since I dont know how to approach this task, I've decided to ask you for your opinion before I leave design stage. Here is how the workflow is about to flow:
users are interacting with website, where they set up demands for service
this demand is being stored (database?) and some kind of message to central system (clustered) is being sent about new demand in database/queue
central system picks up the demand and sends signals to various other systems (clusters) to perform their duties (parts of the demanded service setup)
when they are done, they send up message to central system or the website that the service is now being served
Now, what is the modern, robust, clean and efficient way of storing these requests in some kind of queue, and executing them? Should I send some signals, or should I let all subsystems check the queue/db of any sort for new data? What could be that queue, should it be a database? How to deal with the messages? I thought about opening single tcp connection and sending data over that, along with comands triggering actions/functions on the other end, but at closer inspection, there has to be other, better way. So I found Spring Python, that has been criticized for being so 90's-ish.
I know its a very wide question, but I really hope you can help me wrap my head around that design and not make something stupid here :)
Thanks in advance!
Some general ideas for you:
You could have a master-client approach. Requests would be inserted in the master, stored in a database. Master knows the state of each client (same db). Whenever there is a request, the master redirects it to a free client. The client reports back when has finished the task (including answers if any), making it able to receive a new task from the master (this removes the need for pooling).
Communication could be done using web-services. An HTTP request/post should solve every cases. No need to actually go down to the TCP level.
Just general ideas, hope they're useful.
There are a number of message queue technologies out there which are Python friendly which could serve quite well. The top two that I know of are ActiveMQ and RabbitMQ, which both play well with Python, plus I found this comparison which states that ActiveMQ currently (as of 18 months ago!) outperforms RabbitMQ.
I have a Python-driven web interface powered by Apache 2.2 with mod_python and Python 2.4. I need to make an asynchronous process appear synchronous to users of this web interface.
When users access one module on this website:
An external SOAP interface will be contacted with a unique identifier and will respond with a number N
The external interface will respond asynchronously by contacting a SOAP server on my machine between 1 and 10 times (the number N tells us how many responses we will receive)
I need to somehow aggregate these responses and pass them to the original module which will display the information back to the user. The goal is to make the process appear synchronous to the user.
What is the best way to handle this synchronization issue? Is this something Twisted would be well-suited for?
I am not restricting myself to Python for the solution, though it is preferred because everything else on the server is in Python. I prefer a solution that is both scalable and will take a minimal amount of programming time (though I understand that these attributes are somewhat at odds).
Maybe you can use Orbited to get ajax push with long-lived HTTP connections to your web clients. Orbited is based on Twisted, so I think it makes sense to look at if you already know Twisted. Have a look at this tutorial to get started.
I'm building a website where I hook people up so that they can anonymously vent to strangers. You either choose to be a listener, or a talker, and then you get catapulted into a one-on-one chat room.
The reason for the app's construction is because you often can't vent to friends, because your deepest vulnerabilities can often be leveraged against you later on. (Like it or not, this is a part of human nature. Sad.)
I'm looking for some insight into how I should architect everything. I found this neat tutorial, http://giantflyingsaucer.com/blog/?p=875, which suggests using python & stackless + flash. Someone else suggested I should try using p2p sockets, but I don't even know where to begin to look for info on that.
Any other suggestions? I'd like to keep it simple. :^)
Unless you expect super high load, this is simple enough that it doesn't really matter what you use on the backend: just pick something you're comfortable with. PHP, Python, Ruby, Even a bash script using CGI - your skill level with the language is likely to make more difference that the language features themselves.
I would use an XMPP server like ejabberd or OpenFire to power the backend. XMPP contains everything you need for creating chat/real-time applications. You can use a Flex/Flash Actionscript library like Actionscript 3 XIFF to communicate with the XMPP server.
Flash is user-unfriendly for UI (forms, etc) and it is relatively easy to do what you want using HTML and Javascript on the front-end.
One possible approach for reading the messages would be to regularly do an Ajax request from the server for any new messages. Format the new message and insert it into the DOM.
You will probably need to answer at least these questions before you continue, though:
1) Are you recreating IRQ (everyone sees your posts), or is this a random one-to-one chat, like chatroulette?
1a) Is this a way for a specific person to talk to another specific person, or is this more like twitter?
2) What is your plan for scaling up if this idea takes off? Memcached should probably be a method of last-resort ("bandaid over a bullet-hole"). What's your roadmap for eventually handling a large volume of messages?
3) Is there any way to ignore users? Talk to certain users? Hide your rants from users?
Hey Zach I had to create a socket server for a flash game I made. I built my server in C#, but I would use whatever language your familiar with. If you let me know what your most comfortable with I could try to help find a good tutorial.
The one thing I spent many hours on was getting flash to work from a website with a socket server. With the newer versions of Flash you need to send back a policy file. In my case this needed to be the first chunk of data sent back to the client when they connected to the socket server.
Not sure what to tell you about structuring the back end. I need to know a little bit more about your programming experience. I had an array of all user connections, and was placing them in different "Rooms" so they could play each other. So just some simple arrays and understanding how to send messages to the clients would help you here.
If you have any familiarity with C# I would have no problem sending you the source code for my socket server.
Here is where I am at presently. I am designing a card game with the aim of utilizing major components for future work. The part that is hanging me up is creating a layer of abstraction between the server and the client(s). A server is started, and then one or more clients can connect (locally or remotely). I am designing a thick client but my friend is looking at doing a web-based client. I would like to design the server in a manner that allows a variety of different clients to call a common set of server commands.
So, for a start, I would like to create a 'server' which manages the game rules and player interactions, and a 'client' on the local CLI (I'm running Ubuntu Linux for convenience). I'm attempting to flesh out how the two pieces are supposed to interact, without mandating that future clients be CLI-based or on the local machine.
I've found the following two questions which are beneficial, but don't quite answer the above.
Client Server programming in python?
Evaluate my Python server structure
I don't require anything full-featured right away; I just want to establish the basic mechanisms for abstraction so that the resulting mock-up code reflects the relationship appropriately: there are different assumptions at play with a client/server relationship than with an all-in-one application.
Where do I start? What resources do you recommend?
Disclaimers:
I am familiar with code in a variety of languages and general programming/logic concepts, but have little real experience writing substantial amounts of code. This pet project is an attempt at rectifying this.
Also, I know the information is out there already, but I have the strong impression that I am missing the forest for the trees.
Read up on RESTful architectures.
Your fat client can use REST. It will use urllib2 to make RESTful requests of a server. It can exchange data in JSON notation.
A web client can use REST. It can make simple browser HTTP requests or a Javascript component can make more sophisticated REST requests using JSON.
Your server can be built as a simple WSGI application using any simple WSGI components. You have nice ones in the standard library, or you can use Werkzeug. Your server simply accepts REST requests and makes REST responses. Your server can work in HTML (for a browser) or JSON (for a fat client or Javascript client.)
I would consider basing all server / client interactions on HTTP -- probably with JSON payloads. This doesn't directly allow server-initiated interactions ("server push"), but the (newish but already traditional;-) workaround for that is AJAX-y (even though the X makes little sense as I suggest JSON payloads, not XML ones;-) -- the client initiates an async request (via a separate thread or otherwise) to a special URL on the server, and the server responds to those requests to (in practice) do "pushes". From what you say it looks like the limitations of this approach might not be a problem.
The key advantage of specifying the interactions in such terms is that they're entirely independent from the programming language -- so the web-based client in Javascript will be just as doable as your CLI one in Python, etc etc. Of course, the server can live on localhost as a special case, but there is no constraint for that as the HTTP URLs can specify whatever host is running the server; etc, etc.
First of all, regardless of the locality or type of the client, you will be communicating through an established message-based interface. All clients will be operating based on a common set of requests and responses, and the server will handle and reject these based on their validity according to game state. Whether you are dealing with local clients on the same machine or remote clients via HTTP does not matter whatsoever from an abstraction standpoint, as they will all be communicating through the same set of requests/responses.
What this comes down to is your protocol. Your protocol should be a well-defined and technically sound language between client and server that will allow clients to a) participate effectively, and b) participate fairly. This protocol should define what messages ('moves') a client can do, and when, and how the server will react.
Your protocol should be fully fleshed out and documented before you even start on game logic - the two are intrinsically connected and you will save a lot of wasted time and effort by competely defining your protocol first.
You protocol is the abstraction between client and server and it will also serve as the design document and programming guide for both.
Protocol design is all about state, state transitions, and validation. Game servers usually have a set of fairly common, generic states for each game instance e.g. initialization, lobby, gameplay, pause, recap, close game, etc...
Each one of these states has important state data related with it. For example, a 'lobby' state on the server-side might contain the known state of each player...how long since the last message or ping, what the player is doing (selecting an avatar, switching settings, going to the fridge, etc.). Organizing and managing state and substate data in code is important.
Managing these states, and the associated data requirements for each is a process that should be exquisitely planned out as they are directly related to volume of work and project complexity - this is very important and also great practice if you are using this project to step up into larger things.
Also, you must keep in mind that if you have a game, and you let people play, people will cheat. It's a fact of life. In order to minimize this, you must carefully design your protocol and state management to only ever allow valid state transitions. Never trust a single client packet.
For every permutation of client/server state, you must enforce a limited set of valid game messages, and you must be very careful in what you allow players to do, and when you allow them to do it.
Project complexity is generally exponential and not linear - client/server game programming is usually a good/painful way to learn this. Great question. Hope this helps, and good luck!