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A simple TCP server

Write a program or function that listens for incoming TCP traffic on port N. It offers a simple service: it calculates sum of IP address fields of incoming connection and returns.

Program or function reads integer N from arguments or stdin. It listens to incoming TCP connections on port N. When someone connects to that port, the program calculates sum of its IP address fields and sends it back to the client with trailing newline and closes connection.

Port number N is a valid port, and 2¹⁰ < N < 2¹⁵
Trailing newline can be either \nor \r\n
You can use either IPv4 or IPv6. Since IPv6 addresses are written in hexadecimal form, you must also provide result in same format, for example 2001:0db8:0000:0042:0000:8a2e:0370:7334 => 12ecd.

This is code-golf. Standard rules and loopholes apply.

Example

You run your server with ./server 1234. The server is now running and waiting for connections on port 1234. Then a client from 127.0.0.1 connects to your server. Your server performs a simple calculation: 127+0+0+1 => 128 and sends the result to the client (with trailing newline): 128\n. Then server closes connection and waits for next client.

Leaderboard

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body{text-align:left!important}#answer-list,#language-list{padding:10px;width:290px;float:left}table thead{font-weight:700}table td{padding:5px}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b"> <div id="answer-list"> <h2>Leaderboard</h2> <table class="answer-list"> <thead> <tr><td></td><td>Author</td><td>Language</td><td>Size</td></tr></thead> <tbody id="answers"> </tbody> </table> </div><div id="language-list"> <h2>Winners by Language</h2> <table class="language-list"> <thead> <tr><td>Language</td><td>User</td><td>Score</td></tr></thead> <tbody id="languages"> </tbody> </table> </div><table style="display: none"> <tbody id="answer-template"> <tr><td>{{PLACE}}</td><td>{{NAME}}</td><td>{{LANGUAGE}}</td><td>{{SIZE}}</td><td><a href="{{LINK}}">Link</a></td></tr></tbody> </table> <table style="display: none"> <tbody id="language-template"> <tr><td>{{LANGUAGE}}</td><td>{{NAME}}</td><td>{{SIZE}}</td><td><a href="{{LINK}}">Link</a></td></tr></tbody> </table>

Answer*

PHP, 161 (56?)
========
This is my first post in here. I hope this goes right :)

 <?php $s=socket_create_listen($argv[1]);while($c=socket_accept($s)){socket_getpeername($c,$r);socket_write($c,array_sum(explode('.',$r))."\n");socket_close($c);}

**Ungolfed:**

 <?php 
 $s = socket_create_listen($argv[1]); //Create socket
 while( $c = socket_accept($s) ) { // Loop accepting new connections
 socket_getpeername($c, $r); // Get IP address in $r
 socket_write($c, array_sum(explode('.', $r))."\n"); //Calculate sum
 socket_close($c); //Close connection and wait for next one
 }

**Terminal:**

 $ php test.php 8080 &
 $ telnet localhost 8080
 Trying 127.0.0.1...
 Connected to localhost.
 Escape character is '^]'.
 128
 Connection closed by foreign host.

This only works for IPV4


**Edit**:
I just noticed that php supports basic server: 
I decided stick to original character count unless somebody confirms if following is allowed :)


test2.php: (possible 56-byte solution)

 <?=array_sum(explode('.',$_SERVER['REMOTE_ADDR']))."\n";

And then start service with:

 php -S localhost:8080 test2.php

**Chrome as client**
[![screenshot][1]][1]


 [1]: https://i.sstatic.net/VAaUT.png

**Edit 2: wget as client**

 $ wget -qO- localhost:8080
 128

If this is an answer to a challenge…

…Be sure to follow the challenge specification. However, please refrain from exploiting obvious loopholes. Answers abusing any of the standard loopholes are considered invalid. If you think a specification is unclear or underspecified, comment on the question instead.
…Try to optimize your score. For instance, answers to code-golf challenges should attempt to be as short as possible. You can always include a readable version of the code in addition to the competitive one. Explanations of your answer make it more interesting to read and are very much encouraged.
…Include a short header which indicates the language(s) of your code and its score, as defined by the challenge.

More generally…

…Please make sure to answer the question and provide sufficient detail.
…Avoid asking for help, clarification or responding to other answers (use comments instead).

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\$\begingroup\$ I know rules say: "Program or function reads integer N from arguments or stdin", but is it ok if program in this case is php itself? Or is using builtin server in php considered loophole? \$\endgroup\$

Mikael
– Mikael

2016年03月29日 20:36:56 +00:00
Commented Mar 29, 2016 at 20:36
\$\begingroup\$ Welcome to Programming Puzzles & Code Golf! Your 161-byte solution looks great. Is the 56-byte solution you mentioned the one under test2.php? If so, I think you'd have to ask the OP whether they'd consider that kind of built-in acceptable for this challenge. It isn't a loophole though. \$\endgroup\$

Alex A.
– Alex A.

2016年03月30日 05:13:40 +00:00
Commented Mar 30, 2016 at 5:13
\$\begingroup\$ I would say, using a builtin TCP server would be acceptable, but in this case we talk about a builtin HTTP server. So the 56 byte solution 1) does nothing if the client only connects and sends nothing; 2) sends back only "[Wed Mar 30 10:15:02 2016] 127.0.0.1:47974 Invalid request (Malformed HTTP request)" without running test2.php in case the client sends for example "foo"; 3) sends full set of HTTP response headers before the actual required response in case the client sends valid HTTP request. \$\endgroup\$

manatwork
– manatwork

2016年03月30日 07:19:39 +00:00
Commented Mar 30, 2016 at 7:19
\$\begingroup\$ @Alex A. Thank you and yes, 56-byte solution is under test2.php :) \$\endgroup\$

Mikael
– Mikael

2016年03月30日 14:48:10 +00:00
Commented Mar 30, 2016 at 14:48
\$\begingroup\$ @manatwork You are correct but I was thinking that client is not clearly specified in this task. So is it ok to use browser or even more simplier something like "wget -qO- localhost:8080" as client? \$\endgroup\$

Mikael
– Mikael

2016年03月30日 14:48:21 +00:00
Commented Mar 30, 2016 at 14:48

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