Creating a local HTTP server on android
Some month back, I was trying to implement an app feature that allowed users to communicate(send texts and files) via a local HTTP connection, more like the way Xender works.
I searched for a lot of ways to do this, I found a few libraries but they didn’t offer the speed and simplicity I was looking for.
Eventually, after days of trying different libraries, I found Sun’s HttpServer.
This tutorial assumes you have basic knowledge of Kotlin and android development.
Let’s get started!!
The sun packages are not available on gradle so you’d have to include them in your project’s lib folder.
You can download the two jar files here . (Courtesy of @Oluwalekae)
Copy and paste the files as shown in this picture 👈
In your MainActivity.kt
- create a function to format our client’s inputStream to a string.
2. Declare a variable mHttpServer, data type HttpServer, which will be the instance of our server.
3. Create a method startServer, this is where we would start our server.
4. variable ‘rootHandler’ is an HttpHandler instance used to handle a request to the root path.
You can create as many handlers as you want based on the number of endpoints you want to have.
The mHttpServer.createContext() method allows us assign handlers to endpoints/routes.
We can add a messageHandler, in the end, our MainActivity.kt would look like this.
You can do most operations that you’d normally do on any http server, like Setting headers, handling file uploads, etc.
You can access the server from:
1. your browser from your phone’s browser using “http://127.0.0.1:5000”
2. or another device connected to your phone’s hotspot using “http://192.168.43.1:5000”
because is 5000 is our port number from the code.
Sun httpServer is the fastest server library you can get, trust me.
You can read more about the HttpServer here, and here.
Источник
Ioannis Diamantidis
A few days ago I wrote a post describing how to run an HTTP server from an iOS app. This intrigued me to start investigating how to implement a similar application on an Android app too. So, in this post I will describe how to setup and run an HTTP server from an Android app.
As I mentioned in the iOS post, such a setup (running a server from an app) can be utilized in many ways, with performing usability testing being one of those. If the app under test depends on a backend service, then we could apply some configuration to target the app with the server, which in turn would act as a mock server.
But enough with the intro, let’s move to the action.
Implementation
For the purposes of this app I am going to use Ktor framework to run the server. Ktor is a framework that helps implementing web-based applications and it can be used either on an Android app for the client-side logic or on a Kotlin server-side project. There is also support for Kotlin Multiplatform Projects which enables you to write the networking client code once in Kotlin and then compile to whatever platform you are interested in, for example iOS.
Sadly, Ktor Server is not currently supported but hopefully it will be sooner or later.
Dependencies
On a vanilla Android project, let’s add the dependencies on the app/build.gradle file:
We also have to add the following packagingOptions to avoid any build conflicts
The final app/build.gradle should look like the following:
Permissions
The next step is to add an entry on the AndroidManifest.xml regarding the INTERNET permissions like in the following snippet:
Finally, we can open our MainActivity.kt and add the following content:
We first create a server with Netty as the application engine, 8080 as the port and a module function. Inside this module function, we add the ContentNegotiation feature and register the gson converter. This will allow us to convert the request data to our model and our models to JSON responses. After that, we use the routing feature to define our endpoint and the response. The current implementation returns just a simple map, but it could also return a more complex data structure. Finally we start the server and we explicitly set to wait until we stop it.
We are now ready to run the app. After the app is successfully installed and running on either a device or a simulator, open the browser and hit localhost:8080 .
Voilà! You should get <"message": "Hello world">as a response!
Conclusion
To sum up, in this post we have seen how to run a simple HTTP server from an Android app using Ktor Server. In just 10 lines of code, we manage to create, set up and run an HTTP server. And with the JSON serialization installed.
Thanks for reading and should you have any questions, suggestions or comments, just let me know on Twitter or email me!!
Источник
Android-er
For Android development, from beginner to beginner.
Saturday, February 8, 2014
Android Server/Client example — server side using ServerSocket
It’s the server side implementation of our Server/Client example, the client side is listed in next post «client side using Socket».
 |
| Android Server using ServerSocket |
In this server side implementation, it will list its own IP address when program start. And run in background thread, start a ServerSocket and wait at serverSocket.accept(). Once any request received, it return a message to client side.
Remark: uses-permission of «android.permission.INTERNET» is needed.
47 comments:
Thanks, great examples! Works perfectly when devices are in a local network.
I tried with one device connected using 3G and the other using Wifi, but it didn’t work. Any idea why?
I think you have to set port forwarding on your router.
In the Server example, you start the socketServerReplyThread by calling run() instead of calling start(). Isn’t it a misuse of a thread?
how to connect and test? please help.
Thx for yuor concern.
My point is all network processing should run in background thread. In my implementation, socketServerReplyThread.run() from SocketServerThread, that means both SocketServerThread and SocketServerReplyThread run in a common background thread. I have no idea about any advantage/disadvantage to run in ONE common background thread, or to run in TWO separate background.
Any further advice is welcome:)
hello Sourav Suman,
In my test, both client and server run in a common WiFi network, such that no need to concern port forwarding in router.
In my test, Server crashs, so i created a server in my computer using Perl, i tried to connected using client from my Phone and client return:
IOException.java.net.SocketException: No route to host
You know that is this ? Thanks!
hello Tales Bragança,
Can you make sure your server is reachable? for example, both the server and client are in the same network. Your App have permission of «android.permission.INTERNET».
I have a query . if the client wants to say hello to server. or send any msg how to get it in server. is it possible to add a inputstream reader the server thread. I just to read it but the socket connection is closed
BufferedReader in1 = new BufferedReader(new InputStreamReader(hostThreadSocket.getInputStream();
if (in.ready()) <
String s = in1.readLine();
System.out.println(«manga»);
message+= «replayed: » + msgReply + » «+»server request: «+s;
>
else <
message+= «replayed: » + msgReply + «\n»+»server request»;
>
I tried to connect two devices through wifi-direct using this. but i am getting an ConnectException (Network is unreachable)
can you help me with that?
Hello this is Pushpal Roy. I liked your example.. I tried it too. I created a hotspot in one phone, and connect by wifi to another phone. But its not working. Please help.
hello Subramanian P V,
hello senurz,
I don’t know how to connect with WiFi direct.
hello Pushpal Roy,
I tried to use on WiFi spot, it work. Please check the second video on the above link.
Thank you so much. 🙂 I saw the video of bidirectional communication. And also implemented it successfully. 🙂
But, I’m working on a project in were I need to broadcast a message from the server (for say)to multiple clients connected in the same network. Or any of of the clients to other clients and the server. Actually I’m building a Wi-Fi group chat. Can you please help me in this?
hello Pushpal Roy,
Saw your broadcasting tutorial. Its just awesome!! Thank you so much!
I am not able to download the code.
Please suggest!!
I’m trying to implement smartphone to PC socket. I tried my best to write but still not work. Can you give me some help??
My example is»Server=Smartphone(Android), Client=PC(java)» And can send or response some messages
HI, I get the following error:
Attempt to invoke virtual method ‘void android.widget.TextView.setText(java.lang.CharSequence)’ on a null object reference
Thanks its working fine for WiFi .Do you have any tutorial for same concept for blue tooth.
hello fazil sheriff,
Honestly, it is not a good working example, but may be easy to understand.
I need to communicate between android code and JavaScript code(webView) of same application.
My implementation is as follows,
1. Created serverSocket connection in android as described in your example code. Start this server in onCreate of Activity.
2. Created websocket connection in JavaScript code.
Result:
I am able see some messages being read in serverSocket read() method. Data is related websocket creation details
(http header, connection upgraded to socket, user agent, etc) But I try to send some message to websocket from serverSocket(android code). It is not working.
Note: ServerSocket is listening to port 8080.
Websocket is cerated using URL — «wb:127.0.0.1:8080»
Please let me know if my approach is wrong.
Is it possible to communicate between serverSocket and webSocket?
Sir where is Client said code?
how to send message one client to other using server in between multiple clients on android
client side using Socket is HERE
Great tutorial. I am trying to connect 2 android devices over a tethering wi-fi network. But client side is showing connection refusesd. I’ve added the network permissions in the manifest file as well. Anything I am missing ?
Sir I need android codings to send the messages to the server and I have to read it from my app through the server.Please help me sir.
i have pasted your code but it says «Something wrong! java.net.SocketException
can you help me with it?
This post is likeable, and your blog is very interesting, congratulations 🙂
i am a newbie on android so i just copy and paste it to my project but my prolblem now is how to run this chat application?. .anyone can help me? .thank you
Just connect both mobile to the same WiFi router, suppose it work. Refer to the video.
Hello Andr.oid Eric,
I wanted to ask about the port forwarding. Do you know a good tutorial I can follow to understand how to implement that? Does that mean my server must remain connected to the same router though?
If you don’t mind, may you please take a look at my question on StackOverFlow and try to help me? Any advice or guidance would be greatly appreciated.
Thanks!
Best Regards,
M. Jalil
Just found a good tutorial: http://www.howtogeek.com/66214/how-to-forward-ports-on-your-router/
It mainly depends on your router setting, if your server behind router of HOME network.
IF your server is in MOBILE network, it’s another case: most probably the ISP will block your ports.
Hello Eric
congratulations for your blog.
When I run the server side of your project, it loads but with a message that says «something wrong . «
In your code:
Enumeration enumNetworkInterfaces = NetworkInterface
.getNetworkInterfaces();
gets that message.
would youn tell me, please, the origen of that wrong doing?
Thanks in advance
sir how to save to save the datas from the server socket to database.
Hi I have 2 QUESTIONS:-
1. I am able to run SERVER from phone and CLIENT from Emulator. but i am not able to receive any communication when i run SERVER on emulator and CLIENT on phone. why? shouldnt it work both ways?
2. When i Disconnect my phone from WIFI. then the emulator is not able to connect when i am on my regular 3G network? I cant seem to understand.
It would be nice if you could shed some light on this logic
thanx,
YO!
hello YO!
Sorry, I don’t know how the emulator config!
hello andr.oid Eric,
Your tutorial and blog is awesome as it helped me a lot in creating a server client communication. But it works when the two devices are connected to same network. Do you have any tutorial to connect over different routers? (through IP)
Hello Hands on Science — SAI,
To connect over different routers; I think it very depends on router setting, specially port forwarding. It’s very hard to explain for me.
hello sir , i am having hostinger,s server by using this server i want to implement the android chat application. in chat application the client must use the server as hostinger server .sir plz help me that how can i do this?
hi,
I would like to know one thing(client and server are 2 different projects/apps)
line1 outputStream = hostThreadSocket.getOutputStream();
line2 PrintStream printStream = new PrintStream(outputStream);
line3 printStream.print(msgReply);
line4 printStream.close();
if line3 printstream.print(msgReply) which is server side code is sending some useful message to client.
Now if i want to use that message in my client program, how can i ?
How can i save that message in client project in a variable or anything else? please help.
Refer to the client side Android Server/Client example — client side using Socket: where response in MyClientTask is the message received.
Nice tutorial. Loved it
hi,
i have a big problem. i use usb-Ethernet adapter instead of wifi and connect my android device(192.168.9.1)
with Ethernet cable to my laptop(192.168.9.2).i can ping devices from both side.
i use server side program on my android device(HTC One root).
when i try to connect to server with my laptop (telnet 192.168.9.1 33333) it is not possible and telnet wait until timeout.
i check my android device with OS monitor . server program start and it LISTEN to 192.168.9.1 port 33333 but does not receive any connection.
when i use wifi network every thing OK and i can connect to server.
do you have any idea about it ?
Can you quickly share the repo link?
Android chat is also very important thing to integrate in apps. We should have the knowledge about visitors like from where they are coming?,location, referral etc.
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