Most chat applications can run both server and client simultaneously, well in my case all I need is to connect all devices that uses my app to share data( gson object), in official documentation, I found direct WiFi connection (p2p) which doesn't work if the other device is not on local network, and socket ( server client separated ), which work only one way one device for sending and the other for receiving.
So does anyone have an example of connecting two or more devices trough internet by running both server and client socket in the same time.
It's not so simple. The simplest is that each сleint create server. And every minute was looking for other servers on the local network. For example, sending a certain packet to a port.
Look about it here.
Then you will not care how customers relate to each other.
Related
just want to know is there any methods to allow 2 different apps to communicate. Both of the apps are installed on different devices as well. I had gone throught quite a lot of research, but seem that INTENT, BROADCAST RECEIVER failed to meet my scenario. INTENT, BROADCAST RECEIVER can be work if both of the apps installed on the same device.
Here i can say you can use to make your things work :-
Sockets are typically used to accomplish this between Android devices (or between any peer devices).
When two devices desire to interact, you configure one or both of them to "listen" for connections on a socket and accept a connection from the other when that happens (or you can have a dedicated client and server and the client always initiates the connections).
You can exchange messages after the link has been made.
Android client server socket applications come in a variety of forms, but one that I found handy was:
Example of Android Server/Client using Socket on the client side (and its companion server side blog article - link included in the client blog)
It should be noted that you might need to add your own "protocol" on top of this. For instance, if you are sending a file that is unknown in length without a special "end" character, you might want to add a byte (or several bytes to represent an int, long, etc.) at the beginning to indicate the length of the transmission so the receiving side can tell when it has received everything (or that it has not received everything in case of an error).
connecting via networks (such as most 3G/4G) that forbid inbound connections
Even though there is nothing theoretically blocking sockets from functioning in these situations, many mobile operators will not permit inbound socket connections in practise. You would also need to determine the mobile's public IP address, which is doable but adds complexity. Whether your solution will only ever operate on a single operator's network, you can test it out to see if it works; but, if it doesn't, you could discover that using a server in the "middle" is preferable and easier: Devices A and B establish connections with servers Device A "discovers" device B after requesting the addresses of connected devices from the server. Device A sends device B a message.
Actually, it indicates that the messages should be forwarded to device B while sending them to the server. Device B is informed by the server that a message is available for it (using some sort of message notification like Google Cloud Messaging for example, or simply by the devices polling regularly to see if they have any messages). Device B accesses the server and downloads the messages. The aforementioned will function on pretty much any network that permits internet connectivity. It does have the drawback of having a server, but for the majority of mobile networks, it is probably a necessary approach.
You make one app a server using ServerSocket.
You make the other app a client using a Socket.
With both devices in the same network the client can connect to the server knowing its local ip.
After connection established they can communicate.
I have a situation where I want my computer in my local network to send a notification (push notification, SMS or whatever) to either an IOS of Android device that is on this same LAN. The trick is that I want to send this notification only when the LAN connection to the internet goes down. This means of course that my LAN cannot communicate with email servers, it cannot communicate with any APNs or GCMs, etc.
Is there any way to do this? My computer (the sender) is a Linux box and it will know the local IP addresses for any IOS or Android devices locally.
Yes this is possible.
You either need:
A) A server on the LAN to connect to, that the app knows about (compile-time or runtime configurable). The apps can connect to the server to exchange data, including messages. The server might be HTTPS, and the clients might poll every 5 seconds, or something more refined - using WebSockets.
OR
B) A peer-to-peer scheme. This can get quite complex, particularly given the varying nature of networking for mobile operating systems. As an extreme, you could use UDP for multicasting to multiple devices.
These are just two general examples, and you would need to research how to implement them for your needs. You should start with [A] for prototyping.
Is there a way to push data from local server (hosted on intranet) to an Android application without internet connection? The app is supposed to work only on LAN over wifi. GCM is out of picture as internet connection is not available. However the app will be running on both the devices all the time.
The model, I am talking about, is something like this:
Devices: Local Server - Wifi Connection - Android Device 1, Android Device 2
Android Device 1 updates some data on local server over wifi... Server needs to notify Android Device 2 about the change over Wifi.
Thank You very much for the help
Yes, it is possible.
I used sockets connection to do so.
requestSocket = new Socket();
SocketAddress socketAddress = new InetSocketAddress(ipAddress, portNumber);
requestSocket.connect(socketAddress, timeOutPeriod);
At the server end, you need to open those sockets and ports using whatever languages you prefer. After which you can read or write data using streams.
You should be looking at something like socketIO for that used in a project not that long ago and as long as you know the server address and it is the same on both devices you should be able to push data to and from the server from any device. A group of us used it to make a note taking app. you may need to build your app in html and javascript unless you want to use the java socket communication that would also do the job but more work would be involved.
May be you can implement Message Queue using message server
I have to develop a chatting application and I want to use socket connection. is there a way in android for it. Which will be better way for long time application.
Give me suggestion about it.
Have you looked at the Sockets class? You can use sockets to write and read data between two clients in background threads that update the UI thread with the data received/sent.
Generally with sockets one device (the client) connects to another (the server) and it is expected that the server's hostname will not change. However, you can't guarantee this with devices on mobile networks so a better approach might be to have two devices connect to a well known server that relays chat messages through. If you're just trying to do a basic chat application between devices on the same LAN it would be fine to directly connect them however.
https://developer.android.com/reference/java/net/Socket.html
I'm building a multi-OS mirroring system which I would like to implement using a hybrid client-server and p2p communication method (at least that's the best way I have of describing it).
My issue is that at some point I have a central server (appengine, so there are limitations to what I could do because of time and networking capability constraints) that would need to get a message to a host of different devices which are not necessarily running the same OS (Windows, Android, iOS, Linux, etc...).
Android and iOS (or any other mobile platform) are the main problems it looks like I will be having on 2 levels.
1 - They are both limited by battery power (more so than a laptop and desktops shouldn't have that issue at all), so whichever method I use needs to take that into account.
2 - NAT (harder because the user has relatively less control over their firewall than on a network that they are running). My central server will maintain a table of which device has what IP address, but from what I understand if there is NAT or a firewall it won't be able to get to it if the port was not forwarded.
Since I will be writing a specific client for each OS I prefer a solution that is more universal. I have been leaning towards writing an extremely simple HTTP server that sits on each client and takes requests (which appengine is able to send) and treats them as messages that alert the client to perform an action (either with the server or another client). However, I run into the issue of NAT/firewall. For instance if appengine needs to send a message to AndroidDevice1 it would grab its IP address from a table and make a request to it. However this doesn't work if the ports aren't forwarded correctly, and if the user is on 3g/4g the firewall is controlled by the data provider.
Because of this, I started thinking about using Android C2DM but I want a solution I could implement across platforms.
The only other method I could think of is to just have the client poll the server for messages. This has the battery and network consumption issue though.
Would there be any other way to implement this, and if not, which one of the above methods are best in terms of balancing usability, power and data consumption and user input (the less the user has to do to get the client set up (ie port forwarding, etc...) the better)? Please note that I do not intend for this to become a discussion/flame war but a logical presentation of facts.
Thanks in advance!
You can create a persistent TCP connection from the device to the server and then communicate over this open connection. This would be a very simple connection with keepalive packets for the most part.
In theory this would consume some battery through the radio, but in practice I have experienced that the battery is not affected much at all. Key is to keep the communication over this line to a minimum.
If AppEngine does not allow this approach, you can run your own socket server and then communicate between this server and the appengine server using REST. A socket server I have used is Apache MINA and had no issues with scalability.
Another problem you will have with this approach or any other approach is that on iOS (afaik) you cannot keep a tcp socket open when the App goes into background. The only thing to communicate with the iOS device is Apple Push Notification Service
I would prefer rather than having HTTP Connection you should create TCP/IP tunnel and make communication fast and reliable. I have one Chat application which runs perfact for me using TCP/IP. If you use this you will have same logic for multiple platforms. Only thing you need to write is different code for iOS and android.