I am going to create game for android, this game has multiplayer mode, so it should send ang get some data from server.
Lets assume that 5 players are playing this game.
Each player on his turn sends a word to server, server checks if this word is correct and then server sends this word to other players.
Also server has some kind of timer, and when times goes out it sends to all player then time is up.
Very simple.
Now what is my problem. I have never done web programming and I don't know how to implement server side. Google gived me several options:
Http server
Sockets server
What should I use? One of this options or something else?
Also what frameworks/libraries can be helpful in implimentation? I'd prefer python (like CherryPy if http server is good for my purpouses), but also I can do it on java or c++. Or on php (but I don't want to use it)
Update
After thinking for a while I used python tcp socket server. It seems to be most lightweighted solution for my needs. Also it is easy to interact with it from Java.
Consider using Twisted Python and roll your own simple protocol using persistent connections.
Alternatively, use a normal HTTP(s) server like Apache or nginx and WSGI to tie in your python backend logic. To make it appear as if you have a persistent connection (used to notify everyone of the "word" that was submitted or the expiration of a timer), you'll need to use something like AJAX.
Have you considered using parse?
https://parse.com/
Another good option I like is NodeJS, however you will get alot of the same benefits such as Asynchronous Concurrency from Tornado (Python)
Related
I want to connect my Android App to the back-end. The aim of the project is to filter spam messages. So the app receives SMSs and then should forward it to server for spam filtering which uses machine learning. Now, the thing is we have a python program for machine learning but I don't know how to connect these two things - the Android app and the python program. Need guidance on how the app can send data(sms) and receive response(whether spam of not) to and from the server-side.
A common approach is to connect your client with a web backend that offers a web API (might be a REST API).
Here is a short overview over this topic: https://www.webiotic.com/api-for-mobile-apps/
What you need is a web server which can receive web calls and send back information. A web server in this sense is just a program which listens to incoming HTTP calls.
In your case, this might look like this:
The server is programmed to listen to web calls with the HTTP method POST on the route /checkMessage
It expects the message data in a certain format
For example in JSON with this content: {"message":"Your actual SMS message"}
the server checks its database or triggers a ML job
server returns a result in a specified format. For example this JSON: {"isSpam":true}
Your app then needs to send a POST call to https://www.[YOUR_URL]/checkMessage with the specified data and wait for a response
There are libraries for android which help you with that like Retrofit or OKHttp
As for which technology to use: It's up to you. You can create a web backend in pretty much every language. In your case, you should check out which Python libraries are available to listen to HTTP connections.
Keep in mind that if your app can publicly access your backend, then everybody else can as well. You will want to add some kind of authentication as well.
I'm developing an android app where I would like to fetch some data (mostly text) from the internet but not necesseraly from a website! I would like to have a server that allows clients to fetch some text data. What kind of server fits my goals the best? Http or maybe simply tcp? I don't know much about http so I don't know if it matches my goals and/or if it handles well a kind of text "database".
Edit:
A use case could be: people could write comments and send them to the server. Then clients could refresh their app by fetching new comments from the server. Therefore I'M asking what kind of server could best handle services and kind offre database if needed.
I like using NodeJS in combination with ExpressJS for such purposes. This combination allows you to easily work with HTTP/HTTTPS which is allowed by practically every firewall or proxy server. As of the latter reason I recommend you to use HTTP instead of an own protocol. Furhtermore, Java offers the HTTPURLConnection client which is very easy to use. Moreover, securing traffic with TLS (SSL) is very simple. In addition, NodeJS is resource efficient, runs on Windows, Linux and even on OS X.
For getting the text you can use HTTP GET request handled by the get() method of the Express instance.
This compact tutorial helped me to get familiar with Express on NodeJS.
Without knowing what your use-case is it's difficult to make a good recommendation.
With that said you may find something like https://parse.com/ suitable.
They provide an Android sdk and the 'getting started' tutorials will have you up and running in no time at all.
I'm writing an android app that uses GPS. It sends the NMEA string in a JSON object back to a django app I've already written (for similar use with an arduino+GPS). In order to send the data, I'm using sockets (the socket connection is on a intentservice, the gps code on a regular service).
The sockets are handled by the python tornado webserver, which receives the json object and adds the data to a PostGIS database with the appropriate django model, while still letting me browse the app from a browser like you would normally.
These are both my first android and django apps and I'm looking to improve them as well as my own coding/knolwedge of both platforms.
I'm just wondering if there are better, smarter ways of accomplishing these tasks.
Have a look at this third party rest framework (DRF): http://www.django-rest-framework.org
Gives you a django side solution out of the box. There are others (tasty-py) but in my opinion DRF is the best there is.
No need to do anything with sockets i suppose...
I am supervising a project done by two students that involves retrieving information from a server and displaying it on an android phone. The students have never learnt networking, sql or java before (although they do know how to program) and are only now learning how to setup socketed connections between the phone and a sample server app that i gave them.
They will need to setup a simple sql database on the server on the campus network and be able to communicate with it and only pull information from the database and display it on the phone.
My current plan is that they will receive xml objects generated on the server side sent as a stream through the socket connection. They will then be able to generate a DOM using javax.xml classes and display it as they see fit on the phone itself.
Is this a valid method? What kind of problems can they expect to experience by following this technique? Is there another/better/correct way to do this (without using php or webservices)? The system will be for multiple users so will there be any significant performance issue with the proposed method?
Note 1: The phone never sends any request other than a single multicharacter identifier. The server interprets this identifier and returns information from preprogrammed queries and places it into an xml format.
Webservices sound like the correct approach for this, since you would not want to directly allow communication to the database over the internet.
The book "Unlocking Android" from Manning Publications, ISBN 978-1-933988-67-2 has a Chapter (6) dedicated to "Networking and web services".
Ah and then there is the one and only very nice video from a presentation regarding Android and RESTful webservices from the Google IO.
Couchbase, although from the NoSQL movement have a nice summary as well.
You could use JSON instead of XML, could be easier to parse and work with (feels more lightweight to me at least).
Sorry, forgot the answer for your search of problems:
Activity freezing upon freezing requests: Use additional threads for your requests
How to generally handle high latency
Handle offline behaviour
I'm planning on writing an android app that can view and update data on a local network Oracle DB.
I have already written a python script which checks the oracle db every couple of minutes and writes out XML files which I then plan to parse through my android app to display the data.
As I mentioned though this will only work if the android device is part of the same network (either connected locally or through a vpn), and the XML will be stored on a Unix server.
The question is how to access that Unix server with the android app? Can I use FTP via an android app, or should I be looking to change the python script to send the XML to an easily retrievable location?
EDIT To clarify what you mean, you have a web service running on something like tomcat, the client sends a request to get the data from the oracle db (can also use some form of authentication), the web service responds and sends the data in a format (XML, JSON etc.), the client then sends a request back to the web service to change some data on the oracle db, and in turn it does the clients bidding?
Normally you would create a web service to provide data to mobile clients. There are several reasons for this:
Web services are accessed via HTTP/HTTPS which is a standard protocol and is guaranteed to work on all networks. Corporate wifi networks are especially notorious for locking down protocols except for web and email.
Web services compared to static XML files have an advantage of creating response on the fly. Which means that data will be current.
Web services can take some input parameters and create response based on this parameters.
Authentication: it is a common approach to implement username/passord authentication in the web service, especially if you serve some private data.
Update:
REST is a very popular type of web service. Look at some implementations in Python: Recommendations of Python REST (web services) framework?
This book helped me a lot: http://oreilly.com/catalog/9780596529260
REST is a way of designing your web service. Folks much more intelligent than you and me have divined that all of the work needed for something to work on the net can be handled through a combination of HTTP status codes, HTTP verbs like POST, GET, DELETE, PUT etc. and a clear hierarchy of resources (nouns). It sounds very limiting but it's quite beautiful when it all works together.
Have a look at the Facebook Open Graph API (developers.facebook.com) to get an idea of what a proper REST service looks like.