418: I'm a teapot

Question

As we all should know, there's a HTTP status code 418: I'm a teapot.

Your mission, should you choose to accept it, is to use your creativitea and write the smallest possible server that responds with the above status code to any and every HTTP request made to it.

Standard loopholes apply, including

Fetching the desired output from an external source

This includes doing an HTTP request to fetch the page with the question and extracting a solution from that page. This was mildly amusing back in 2011, but now is derivative and uninteresting.

Meaning you cannot simply redirect the request to another server to have it return the response.

Your server can do anything (or nothing) while no HTTP request is made to it as long as it replies with the correct response once a HTTP request is made.

Answer 1

GNU Awk: 69 characters

A server itself (endlessly serves one request at a time), no library used.

Send 418 to everybody who connects (82 69 characters):

BEGIN{while(s="/inet/tcp/80/0/0"){print"HTTP/1.1 418\n"|&s
close(s)}}

Send 418 to everybody who sends something (93 80 characters):

BEGIN{while(s="/inet/tcp/80/0/0"){s|&getline
print"HTTP/1.1 418\n"|&s
close(s)}}

Send 418 to everybody who sends a valid HTTP GET request (122 109 characters):

BEGIN{while(s="/inet/tcp/80/0/0"){s|&getline
if(/^GET \S+ HTTP\/1\.[01]$/)print"HTTP/1.1 418\n"|&s
close(s)}}

Answer 2

Bash (33)

nc -lp80 -q1<<<"HTTP/1.1 418
";$0

Answer 3

PHP - 85 bytes

<?for($s=socket_create_listen(80);socket_write(socket_accept($s),"HTTP/1.1 418
"););

Saved with Windows-Style (CR-LF) line endings, requires php_sockets enabled.

I actually used this as my error code for the Hard Code Golf: Create a Chatroom challenge, but no one noticed.

---

Browser-Friendly version

<?for(socket_getsockname($s=socket_create_listen(80),$n);$t="I'm a teapot";socket_write($c=socket_accept($s),"HTTP/1.0 418 $t
Content-Length: $l

<title>418 $t</title><h1>$t</h1>The requested resource is not suitable for brewing coffee.<hr><i>$n:80</i>"))$l=124+strlen($n);

Start the script in the CLI, and point your browser at http://localhost.

Answer 4

Node.js (LiveScript)

http module - 66

require(\http)createServer (->&1.writeHead 418;&1.end!) .listen 80

Inspired by Qwertiy's answer.

net module - 76

require(\net)createServer (->it.write 'HTTP/1.1 418\r\n';it.end!) .listen 80

Answer 5

Ruby + Rack, 19 bytes

run->e{[418,{},[]]}

Must be saved as config.ru, and run with the rackup command.

Or if you prefer "pure" Ruby:

Rack::Handler::WEBrick.run->e{[418,{},[]]}

42 bytes + -rrack flag = 48 bytes

Answer 6

Bash+BSD general commands, 29

Borrowing back a little bit from other answers:

nc -lp80<<<"HTTP/1.1 418
";$0

Works for me with wget.

First answer to use nc, 38

for((;;)){
nc -l 80 <<<HTTP/1.1\ 418
}

I'm assuming root privileges - run as follows:

sudo bash ./418.sh

Answer 7

Ruby (nc system command) - 35

loop{`nc -l 80 <<<"HTTP/1.1 418"`}

DigitalTrauma should get the credit for the idea of using nc, however Ruby can make an infinite loop with fewer characters than Bash :)

Ruby (TCPServer) - 75

require'socket'
s=TCPServer.new 80
loop{(s.accept<<'HTTP/1.1 418
').close}

That newline is intentional -- the actual newline character is one character shorter than "\n".

Ruby (WEBrick HTTPServer) - 87

require'webrick'
(s=WEBrick::HTTPServer.new).mount_proc(?/){|_,r|r.status=418}
s.start

Answer 8

Node.js, 72

require('http').createServer((q,s)=>s.writeHead(418)+s.end()).listen(80)

Response:

HTTP/1.1 418 I'm a Teapot
Date: Thu, 01 Apr 2021 16:12:59 GMT
Connection: keep-alive
Transfer-Encoding: chunked

0

---

Node.js, 80 with ES5 syntax only

require('http').createServer(function(q,s){s.writeHead(418);s.end()}).listen(80)

The response is

HTTP/1.1 418 I'm a teapot
Date: Wed, 19 Nov 2014 21:08:27 GMT
Connection: keep-alive
Transfer-Encoding: chunked

0

Answer 9

Python 3 106

s=__import__('socket').socket(2,1) 
s.bind(('',80))
s.listen(9)
while 1:s.accept()[0].send('HTTP/1.1 418\n')

Answer 10

Haskell - 142 bytes

import Network
import System.IO
main=listenOn(PortNumber 8888)>>=f
f s=do{(h,_,_)<-accept s;hPutStr h"HTTP/1.1 418\r\n";hFlush h;hClose h;f s}

Answer 11

R, 80 characters

Never did socket programming with R before, but I'll give it a try:

repeat{s=socketConnection(,80,T,open="r+");cat("HTTP/1.1 418\n",file=s);close(s)}

Here socketConnection opens a socket: first argument should be the host, the default being localhost we can skip it here; the second argument is the port which has no default, then argument server when specified TRUE creates the socket, if FALSE it just connects to an existing one. T is, by default, equals to TRUE, in R.

Edit: As suggested in a suggested edit by @AlexBrown, this could be shorten into 69 characters:

repeat cat("HTTP/1.1 418\n",file=s<-socketConnection(,80,T))+close(s)

Answer 12

Shell + socat, 60

socat tcp-l:80,fork exec:'printf HTTP/1.1\\ 418\\ T\r\n\r\n'

Answer 13

Tcl (>= 8.5), 78 bytes

Edit - added in an extra newline (total of 2 newlines) for the sake of compliance.

socket -server {apply {{c - -} {puts $c "HTTP/1.1 418
";close $c}}} 80
vwait f

Answer 14

Powershell, 398

$Listener = New-Object System.Net.Sockets.TcpListener([System.Net.IPAddress]::Parse("10.10.10.10"), 80)
$Listener.Start()
while($true)
{
    $RemoteClient = $Listener.AcceptTcpClient()
    $Stream = $RemoteClient.GetStream()
    $Writer = New-Object System.IO.StreamWriter $Stream
    $Writer.Write("HTTP/1.1 418 I'm a Teapot`nConnection: Close`n`n")
    $Writer.Flush()
    $RemoteClient.Close()
}

258

$l=New-Object System.Net.Sockets.TcpListener([System.Net.IPAddress]::Parse("10.10.10.10"),80);$l.Start();while($true){$r = $l.AcceptTcpClient();$s = $r.GetStream();$w = New-Object System.IO.StreamWriter $s;$w.Write("HTTP/1.1 418`n`n");$w.Flush();$r.Close()}

Answer 15

Julia 0.6, 86 73 bytes

s=listen(80)
while 1<2
c=accept(s)
write(c,"HTTP/1.1 418

")
close(c)
end

Answer 16

Node.js koa, 61 Bytes

require('koa')().use(function*(){this.status=418}).listen(80)

Response:

HTTP/1.1 418 I'm a teapot
X-Powered-By: koa
Content-Type: text/plain; charset=utf-8
Content-Length: 12
Date: Thu, 20 Nov 2014 07:20:36 GMT
Connection: close

I'm a teapot

Requires node v0.11.12 +

Run as:

node --harmony app.js

Answer 17

MATLAB, 97 86 bytes

Not really a serious contender in terms of absolute byte-count, but I'd like to post it because I didn't think it would be possible to write a fully functional webserver using a mathematical tool. Note the use of property shortening: 'Ne','s' internally expands to 'NetworkRole', 'server'.

t=tcpip('0.0.0.0','Ne','s');while 1
fopen(t)
fprintf(t,'HTTP/1.1 418\n')
fclose(t)
end

Answer 18

Perl, 78

use Web::Simple;sub dispatch_request{sub{[418,[],[]]}}__PACKAGE__->to_psgi_app

run as plackup whatever.pl.

Answer 19

Go, 162 bytes

package main
import "net/http"
func main(){http.HandleFunc("/",func(w http.ResponseWriter,r *http.Request){w.WriteHeader(418)})
http.ListenAndServe(":80", nil)
}

Answer 20

Python 2.7/Django, 94 bytes

(added from default boilerplate from django-admin.py startproject) In urls.py:

import django.http.HttpResponse as r;urlpatterns=patterns(url(r'^*$',lambda q:r(status=418)))

Answer 21

node.js with CoffeeScript (76)

require("connect")().use((q,s,n)->s.writeHead 418;s.end();return;).listen 80

Just compile it to JavaScript, then you need to run npm install connect. After that start it with node server.js

Answer 22

Factor, 101 141 bytes

[ utf8 <threaded-server> readln 10 base> >>insecure [ "HTTP/1.1 418\r" print flush ] >>handler [ start-server ] in-thread start-server drop ]

Return 418 to everyone who connects.

Answer 23

You can do this with minimal effort using a .htaccess file and php.

All the accesses to your server will return the status 418.

Below is the code:

.htaccess (28 bytes)

RewriteRule .* index.php [L]

PHP (38 19 bytes)

<<?header(TE,1,418);

---

Thanks to @primo for saving me a bunch of bytes!

---

I have tested this and confirm it returns the desired result!

By the way, "Pedido" means "Request" and "Resposta" means "Answer".

Answer 24

05AB1E + ncat, 75 74 69 62 44 42 bytes

-12 thanks to ovs.

'‚«™’ÿ.¬•"n—Ä -k¯à80<<<'HTTP/1.1 418
'"’.E

Your ISP must be AT&T for this to work, as it abuses AT&T's automatic conversion of \n to \r\n in HTTP requests.

'‚«™’...’.E  # trimmed program
         .E  # evaluate...
    ’...’    # "ÿ.shell\"ncat -klp80<<<'HTTP/1.1 418\n'\""...
             # (implicit) with ÿ replaced by...
'‚«          # "system"...
   ™         # in title case...
         .E  # as Elixir code

====================

System.shell"..."  # trimmed program
System.shell       # execute shell command...
            "..."  # literal

====================

ncat -klp80<<<'...'  # trimmed program
ncat                 # host web server...
     - l             # that listens to requests...
     -k              # forever...
     -  p            # on port...
         80          # literal...
ncat                 # that returns response input...
           <<<       # with...
              '...'  # literal...
           <<<       # as input

_{Side note: I do not know Elixir at all so if there are ways to improve the Elixir code please let me know.}

05AB1E (legacy) + ncat, 64 54 52 bytes

’__£Ø__('ï´').‚«("n—Ä -k¯à80<<<'HTTP/1.1 418\n'")’.E

---

’...’.E  # trimmed program
     .E  # evaluate...
’...’    # "__import__('os').system(\"ncat -klp80<<<'HTTP/1.1 418\n'\")"...
     .E  # as Python code

====================

__import__('os').system("...")  # trimmed program
__import__('os').system(     )  # execute shell command...
                        "..."   # literal

====================

ncat -klp80<<<'...'  # trimmed program
ncat                 # host web server...
     - l             # that listens to requests...
     -k              # forever...
     -  p            # on port...
         80          # literal...
ncat                 # that returns response input...
           <<<       # with...
              '...'  # literal...
           <<<       # as input

Answer 25

C# + OWIN 251 240

I was really hoping it'd be shorter, but the long namespaces ruined that plan. Requires the Microsoft.Owin.SelfHost package available on NuGet.

using Owin;class P{static void Main(){Microsoft.Owin.Hosting.WebApp.Start<P>("http://localhost");while(0<1);}public void Configuration(IAppBuilder a){a.Run(c=>{c.Response.StatusCode=418;return System.Threading.Tasks.Task.FromResult(0);});}}

Answer 26

node.js with connect (78)

require('connect')().use(function(q,s,n){s.writeHead(418);s.end()}).listen(80)

You need to run npm install connect first. Then start it with node server.js

Answer 27

nginx - 35

events{}http{server{return 418;}}

Throw that in nginx.conf, start nginx.

Not sure if this uses standard loopholes "Using built-in functions to do the work" or "Interpreting the challenge too literally." Oops, looks like OP won't like this answer.

Answer 28

Java 7, 208 bytes

import java.net.*;class R{public static void main(String[]a)throws Exception{for(ServerSocket s=new ServerSocket(80);;){Socket p=s.accept();p.getOutputStream().write("HTTP/1.0 418\n".getBytes());p.close();}}}

This question needed a java answer.

poke@server ~
$ curl -i localhost:80
HTTP/1.0 418

Answer 29

Python 3 + Flask, 64 80 76 75 bytes

from flask import*
a=Flask("");a.route("/")(lambda:abort(418));a.run("",80)

I don't know much Flask, so I'm not entirely sure if this works. Please let me know in the comments if there's some problem with this. Ungolfed version:

from flask import Flask, abort

app = Flask(__name__)

@app.route("/")
def index():
    abort(418)

app.run("127.0.0.1", 80)

Simply binds the path "/" to a function that aborts with error code 418.

Thanks to Makonede for pointing out that I didn't start the server and giving a modification to make the solution 80 76 75 bytes. The 80 was from using app instead of a. Oops! The 76 was from (a:=Flask("")) instead of a=Flask("");a.

Answer 30

Python 3 + ncat, 55 53 bytes

import os;os.system("ncat -klp80<<<'HTTP/1.1 418\n'")

Your ISP must be AT&T for this to work.

import os;os.system("...")  # trimmed program
import                      # import module named...
       os                   # variable
          os.system(     )  # run shell command...
                    "..."   # literal

====================

ncat -klp80<<<'...'  # trimmed program
ncat                 # host web server...
     - l             # that listens to requests...
     -k              # forever...
     -  p            # on port...
         80          # literal...
ncat                 # that returns response input...
           <<<       # with...
              '...'  # literal...
           <<<       # as input